Merge branch 'main' into feat/preset-plugin-apis

fix: update demo plugins
fix: remove async behavior and clang-tidy
2026-10-17 20:57:26 +00:00 · 2026-10-17 15:18:45 +08:00 · 2026-10-17 15:09:21 +08:00 · 2026-10-17 15:09:06 +08:00 · 2026-10-17 01:44:15 +08:00 · 2026-10-16 21:59:48 +08:00
20 changed files with 2677 additions and 100 deletions
@@ -574,8 +574,7 @@ DMABUF workaround and then branches on `GDK_BACKEND` (an `x11` prefix means the
 paths, when `/proc/driver/nvidia/version` exists and the linked WebKitGTK honours the switch (>= 2.44,
 `WebView::SupportsForceSharedMemory()`), it sets `WEBKIT_DMABUF_RENDERER_FORCE_SHM=1` and
 `WEBKIT_FORCE_DMABUF_RENDERER=1` (non-replacing): the proprietary driver cannot back WebKit's hardware
-DMABUF renderer. On a hypervisor guest (`/proc/cpuinfo` `hypervisor` flag) and WebKitGTK >= 2.44 it sets
-`WEBKIT_DMABUF_RENDERER_FORCE_SHM=1` alone, since virtual GPUs cannot back the hardware path either. On the default path it forces `GDK_BACKEND=x11` when wx lacks EGL and `WAYLAND_DISPLAY`
+DMABUF renderer. On the default path it forces `GDK_BACKEND=x11` when wx lacks EGL and `WAYLAND_DISPLAY`
 is set, and sets `WEBKIT_DISABLE_COMPOSITING_MODE=1` (non-replacing) inside that branch when the linked
 WebKitGTK is older than 2.42: a forced X11 backend in a Wayland session is the only default-path case
 that runs through XWayland, which `DISPLAY` and `WAYLAND_DISPLAY` alone do not tell you (a native
@@ -568,18 +568,13 @@ vue-resize workaround script and sets a persistent SQLite cookie store on the vi
 ## WebKitGTK on Linux sessions

 **Mechanism.** `CLI::run` (`src/OrcaSlicer.cpp`, under `#ifdef __WXGTK__`, before GTK initialises)
-sets the DMABUF workarounds and then branches on `GDK_BACKEND`:
+sets the NVIDIA DMABUF workaround and then branches on `GDK_BACKEND`:
 - **Both paths**, before the split: when `/proc/driver/nvidia/version` exists and the linked WebKitGTK
  honours the switch (>= 2.44, `WebView::SupportsForceSharedMemory()`), it sets
  `WEBKIT_DMABUF_RENDERER_FORCE_SHM=1` and `WEBKIT_FORCE_DMABUF_RENDERER=1` non-replacing. The
  proprietary driver cannot back WebKit's hardware DMABUF renderer, so the shared-memory transport keeps
  accelerated compositing instead of dropping it; `WEBKIT_FORCE_DMABUF_RENDERER` clears the
  Debian/Ubuntu/openSUSE `isNVIDIA()` early return, which otherwise returns before the FORCE_SHM check.
- **Hypervisor guests**, same position: when `is_hypervisor_guest()` (the `hypervisor` flag in
-  `/proc/cpuinfo`) and WebKitGTK >= 2.44, it sets `WEBKIT_DMABUF_RENDERER_FORCE_SHM=1` non-replacing.
-  Virtual GPUs (VirtualBox VMSVGA, VMware, QEMU) cannot back the hardware DMABUF path either, and
-  FORCE_SHM alone was confirmed to fix web views in VirtualBox; the `WEBKIT_FORCE_DMABUF_RENDERER` pair
-  is not needed without the Debian `isNVIDIA()` patch. The flag is x86-only, so ARM guests are not covered.
 - **Default path** (`GDK_BACKEND` unset or not starting with `x11`): if wx lacks EGL (`!wxHAS_EGL`) and
  `WAYLAND_DISPLAY` is set, it forces `GDK_BACKEND=x11`, and in that same branch it sets
  `WEBKIT_DISABLE_COMPOSITING_MODE=1` non-replacing when the linked WebKitGTK predates 2.42
@@ -595,9 +590,9 @@ Runtime backend detection elsewhere uses Orca's `is_running_on_wayland()` / `is_
 (see `references/platforms.md`), not these environment variables.

 **Pitfall.**
- **Rule:** On NVIDIA and hypervisor guests reach for `WEBKIT_DMABUF_RENDERER_FORCE_SHM` before
-  `WEBKIT_DISABLE_COMPOSITING_MODE`. **Why:** the proprietary driver and virtual GPUs cannot back WebKit's
-  hardware DMABUF renderer, leaving web views blank or slow; FORCE_SHM keeps accelerated compositing and only
+- **Rule:** On NVIDIA reach for `WEBKIT_DMABUF_RENDERER_FORCE_SHM` before
+  `WEBKIT_DISABLE_COMPOSITING_MODE`. **Why:** the proprietary driver cannot back WebKit's hardware
+  DMABUF renderer, leaving web views blank or slow; FORCE_SHM keeps accelerated compositing and only
  skips the hardware path, while disabling compositing drops it. Threaded scrolling is a separate,
  release-dependent default (off in 2.44/2.45, on from 2.46). `WEBKIT_DISABLE_DMABUF_RENDERER` is not a
  substitute — it is read first, leaves the transport set empty (no compositing from 2.44 on, where the
@@ -0,0 +1,252 @@
+# Preset Plugin API — High Level Design
+
+## Purpose and scope
+
+The preset plugin API lets Python plugins update the presets OrcaSlicer is using,
+so users do not have to perform every routine setting change by hand. It covers
+process, printer, and filament presets. All three use one staged update lifecycle;
+the way a target is selected is specific to the preset type.
+
+The API edits Orca's managed edited preset, not a detached copy or a saved preset
+behind the UI's back. It does not save to disk. Saving, discarding, and transferring
+unsaved edits remain under Orca's existing preset workflow.
+
+The API does not create or delete presets or provide off-tab editing. For filament,
+choosing a different `preset_name` as the update target also selects that preset for
+the requested slot, following the normal UI flow. A standalone slot-assignment or
+preset-fork operation is outside this API's contract.
+
+## Preset and slot model
+
+Each preset collection maintains a managed edited copy for its selected preset.
+Settings tabs apply changes to that copy and own the normal dirty-state, validation,
+save/discard/transfer, and downstream refresh behavior. Plugin updates must use the
+same path so that the settings tab, dirty indicators, and effective print
+configuration observe a consistent state.
+
+Filament selection adds a slot-to-preset mapping. `PresetBundle::filaments` is the
+catalog, while `PresetBundle::filament_presets` maps each slot to a preset name.
+Several slots may refer to the same preset. A filament update edits that shared
+preset, so all slots referring to it are affected. Slot numbers exposed by the API
+are 1-based, matching the UI.
+
+## API shape
+
+Each preset API exposes `begin_update()`, which selects and binds one target, and
+returns a transaction. The transaction stages setting changes using `set()` and
+applies them only on explicit `commit()`.
+
+```python
+# Filament is targeted by its 1-based slot. Omitting preset_name keeps the
+# preset currently assigned to the slot; providing it selects that preset for
+# the slot before staging updates.
+tx = orca.host.preset.filament.begin_update(
+    slot_number=2,
+    preset_name="Generic PLA"
+)
+tx.set("filament_flow_ratio", "0.98")
+tx.set("filament_retract_length", "0.8")
+result = tx.commit()
+
+# Process and printer default to their active presets. A caller can request a
+# different preset that is selectable in the corresponding UI dropdown.
+tx = orca.host.preset.process.begin_update(
+    preset_name="0.20mm Standard"
+)
+tx.set("layer_height", "0.2")
+tx.commit()
+```
+
+The example is the API contract, and the Python bridge provides it. `begin_update()`
+is synchronous: it blocks the background Script worker until the target selection and
+any unsaved-edit dialog settle, then returns the bound transaction. Orca's UI thread
+stays responsive because the Script capability runs on its own worker. `set()` and
+`commit()` run synchronously on that same worker. The Script worker and its optional
+coroutine loop are described in
+[python-plugin-async-bridge.md](python-plugin-async-bridge.md).
+
+### Target resolution
+
+- **Filament:** `slot_number` identifies the slot. If `preset_name` is omitted,
+  the transaction targets the preset currently assigned to that slot. If supplied,
+  it requests that preset for the slot and selects it through the normal UI flow;
+  the name must be among the presets offered by that slot's dropdown, with one
+  exception: the preset currently assigned to the slot stays targetable even when the
+  slot's dropdown hides it (for example an incompatible-but-selected preset). Selecting
+  a different preset changes the slot-to-preset mapping. In both cases the transaction
+  edits the shared preset, not an isolated slot override.
+- **Process and printer:** omitting `preset_name` targets the currently active
+  preset. Supplying `preset_name` requests the preset by the name shown in its
+  dropdown. It must be one of the choices the dropdown currently offers, rather
+  than merely any preset present in the collection. This is particularly important
+  for process presets, whose selectable choices can depend on the current context.
+- A transaction targets exactly one preset. Multi-preset transactions are not
+  supported: applying them would require switching among targets while the
+  application has only one managed edited copy per collection.
+
+Targets are resolved through Orca's normal preset-selection model. The API should
+not accept raw preset pointers or filesystem paths as target identities. A missing,
+unavailable, or ambiguous target fails explicitly instead of silently selecting a
+different preset.
+
+## Selection and user interaction
+
+`begin_update()` resolves its target through shared binding helpers
+(`bind_preset_target` for process/printer, `bind_filament_target` for filament) and
+performs the selection only when the requested target differs from the active target;
+otherwise it returns a transaction without switching. The helpers use Orca's normal
+preset selection flow, `Tab::select_preset()`, including updating a filament slot
+assignment when requested. If the normal selection flow requires user input, it opens
+the relevant existing dialog(s), including unsaved-edit choices such as save, discard,
+or transfer. The call remains blocked on the Script worker until those interactions
+finish; it returns the bound transaction, or raises on a cancellation, without
+applying staged settings. A canceled selection does not change the requested target or
+filament slot assignment, but it does not roll back decisions the user already accepted
+in an earlier dialog. The helpers then confirm that the requested preset actually
+became the edited preset; a successful selection request alone is not sufficient. There
+is no separate `switch_preset` plugin API.
+
+If the requested target is already active, `begin_update()` returns without a
+selection prompt, apart from the UI-thread dispatch needed to bind the transaction.
+If a different preset is requested, Orca selects it through the normal UI flow. For
+filament, this also updates the requested slot's assignment when `preset_name`
+differs from its current assignment. When the current preset has unsaved changes,
+the Script worker stays blocked until the user chooses among Orca's existing options,
+such as transfer, discard, or cancel.
+
+The API never suppresses that warning, chooses an option for the user, or switches
+away from dirty edits silently. Cancel aborts the operation before any staged target
+changes are applied. Process and printer updates follow this rule too when the
+plugin requests a different `preset_name`; they normally return immediately when
+the active preset is the target.
+
+## Staging and commit semantics
+
+`set(key, value)` stages a serialized config value and does not mutate the preset.
+The transaction is the boundary for a related group of changes, avoiding
+intermediate partially-updated states. `commit()` runs synchronously on the background
+Script worker. At commit, the API validates keys and values against the target preset
+type and applies the batch through `Tab::apply_preset_config_values`, the existing tab
+and settings-group update path. Existing setting-specific validation, correction, and
+callbacks remain authoritative; plugin updates do not create a parallel setter with
+different behavior.
+
+A successful commit updates dirty state and downstream configuration/Plater state
+once for the batch. The edited preset remains unsaved; persistence continues through
+Orca's normal save action. A validation or commit failure restores the edited preset's
+config to its pre-batch state and recomputes the state derived from it (compatibility
+marks, the preset selector, dependent tabs, the Plater and the printer agent), so no
+staged setting is left partially applied. That guarantee is limited to the edited
+preset and its config-derived state: an `on_change` callback is a GUI method, not a pure
+function of the config, so the transaction does not reverse a preset or slot selection
+made while resolving the target, a dialog decision the user already accepted, an undo
+snapshot, a dependent preset's rewritten config, or anything already sent to a device.
+Exact all-or-nothing across those external effects is not achievable while the
+authoritative GUI callbacks run; the boundary is documented on
+`Tab::apply_preset_config_values`. A filament slot assignment made as part of target
+selection is likewise not a staged setting: after the user accepts the selection flow it
+may remain changed even if a later commit fails, and the API does not switch back or
+reverse the user's selection or any accepted transfer/discard decision for the previous
+preset.
+
+## Outcomes and consistency
+
+The API distinguishes target resolution failures, invalid setting/value, user
+cancellation, stale filament-slot mapping, and commit failure. A result identifies
+the target preset, whether preset selection changed, and (for filament) whether the
+slot assignment changed and which slots share the edited preset. A canceled
+selection applies neither the requested slot assignment nor staged target changes;
+a failed commit applies none of the staged target settings.
+
+Filament slot assignments can change between `begin_update()` and `commit()`. The API
+detects that and rejects a stale operation instead of silently editing the new
+slot assignment. It must not hold raw preset pointers across reloads. Conflicting
+duplicate writes to one setting in a transaction are rejected rather than resolved
+by incidental call order.
+
+The existing one-setting filament call,
+`orca.host.preset.filament.update(slot_number, key, value)`, remains available as a
+compatibility shorthand. It shares the staged API's target resolution, selection,
+validation, and commit path, and it is synchronous like `begin_update()`: both block
+the background Script worker while any selection dialog settles.
+
+## Design principles
+
+- **Reduce routine interaction, preserve agency.** Clean switches should be
+  seamless; unsaved user work must still receive the normal warning and decision.
+- **One source of truth.** UI and plugins share the managed edited copy and setting
+  update path, including validation and callbacks.
+- **The UI workflow is authoritative.** The API must enter through the same
+  selection and setting-change workflows as the UI, not reproduce their logic or
+  write config values directly. This keeps existing and future side effects active:
+  `on_change` handling for mutually exclusive, invalid, or out-of-range settings;
+  compatibility and dependent-preset updates; and printer-agent changes when the
+  selected printer changes.
+- **Explicit target and explicit commit.** Plugins know which preset they edit and
+  when staged changes become visible.
+- **No hidden persistence.** Plugin edits remain unsaved until the user saves them
+  through Orca.
+- **Shared means shared.** Editing a filament preset through one slot affects every
+  slot assigned to it. Choosing another preset for a slot is explicit in
+  `preset_name`; slot-specific divergence would require a separate fork operation.
+- **Consistent lifecycle, type-specific targeting.** Process, printer, and
+  filament share transaction and error semantics while respecting their existing
+  selection models.
+
+## Implementation in the current codebase
+
+The transaction API is implemented. The current plugin surface exposes `begin_update()`,
+`PresetTransaction` with `set()`/`commit()`, and the per-setting `update()` compatibility
+shorthand. For filament, `update_filament_slot()` resolves the preset already assigned
+to a slot, selects it through `Tab::select_preset()`, and applies one setting through
+`Tab::apply_preset_config_values()`; it does not change the slot assignment.
+
+`begin_update()` and `update()` are synchronous blocking calls
+(`begin_preset_update` / `begin_filament_update`). They marshal the target binding to
+the UI thread and block the background Script worker until the selection settles, so
+the wait never blocks the UI thread. They are valid only on that worker, never from the
+UI thread or a slicing pipeline hook.
+
+`Tab::select_preset()` is the basis for switching to process, printer, or filament
+presets and for invoking the normal unsaved-edit flow. The flow is type-specific: a
+process selection can trigger compatibility handling for filaments, and a printer
+selection can involve technology changes and dependent preset compatibility. It may
+therefore show more than one dialog. Cancellation of a later step does not necessarily
+undo decisions the user already accepted in an earlier dialog. Target resolution
+preserves those side effects and then verifies the resulting edited target.
+
+Filament `preset_name` is an additional integration on top of `Tab::select_preset()`:
+selecting a different name for a slot also updates the slot-to-preset mapping and its
+dependent UI/configuration state, mirroring the filament branch of the Plater's normal
+selection path (`PresetBundle::set_filament_preset()` plus the project/selection refresh,
+the dynamic filament list, the conditional support-filament flushing recalc, the slot
+combo refresh and its AMS sync badge). A mixed-color virtual slot is not targetable.
+
+Process and printer dropdown choices are constrained by visibility and compatibility,
+and compatibility may depend on the active context. Target resolution checks the tab
+dropdown's actual items before the selection flow, so a target the user cannot pick
+fails without raising that flow's unsaved-edit prompt; a name two entries carry is
+rejected as ambiguous. A filament `preset_name` resolves against the requested slot's
+own sidebar selector rather than the tab's, so that slot's compatibility filter is the
+one that applies. A name the slot's dropdown does not show is rejected unless it names
+that slot's current assignment (a hidden or incompatible-but-selected preset), which
+stays targetable.
+
+`commit()` applies its batch through `Tab::apply_preset_config_values`, which parses and
+validates the whole batch before touching the edited preset and restores the edited
+preset and its config-derived state on failure (see "Staging and commit semantics" for
+the limit of that rollback). Since `begin_update()` performs target selection before the
+caller stages values, invalid staged values can still follow a user-visible selection
+prompt; that is a consequence of this API shape and remains explicit in its behavior.
+
+## Integration boundary
+
+The plugin API coordinates target resolution, preset selection, staged values, and
+the settings commit path. It does not own or duplicate preset dirty-state logic,
+selection prompts, setting validation, or persistence. Target changes flow through
+the same UI selection path so dependent behavior—such as selecting the printer
+agent—still runs. Setting changes flow through the same UI change path so `on_change`
+and related validation/correction behavior still runs. The integration bridges UI
+prompts to the Python operation through the blocking `begin_update()` and reuses
+the normal Plater slot-selection behavior for explicit filament targets, and commits a
+batch without losing existing per-setting behavior.
@@ -0,0 +1,351 @@
+# Python plugin async bridge — High Level Design
+
+## Purpose and scope
+
+The embedded Python plugin runtime runs most capability calls synchronously: a C++ call site acquires
+the GIL and the capability's Python method runs to completion on the calling thread. The staged preset
+update (`begin_update()` in [preset-plugin-api.md](preset-plugin-api.md)) is also synchronous, but
+its target selection can open unsaved-edit dialogs. It therefore blocks the Script worker, not the UI
+thread, and returns only when the selection settles.
+
+This document describes the Script capability's background execution path, including the optional
+per-invocation asyncio loop for an `async def execute`, and the blocking UI marshalling that host calls
+use from that worker. The bridge is deliberately narrow: only the Script capability gains a
+background/async execution path. Every other capability — including the SlicingPipeline hooks — stays
+synchronous on its caller's thread.
+
+## Execution baseline
+
+### How a capability call runs
+
+A capability instance is a Python object owned through `Slic3r::PluginInstanceHandle`
+(`src/slic3r/plugin/PythonPluginBridge.cpp`) and handed to the rest of the program as a
+`std::shared_ptr<Slic3r::PluginCapabilityInterface>`. Its identity (`name()`, `type()`,
+`audit_plugin_key()`) is resolved once at materialization and cached in C++
+(`PluginCapabilityInterface` in `src/slic3r/plugin/PythonPluginInterface.hpp`).
+
+Every C++→Python call crosses a trampoline method. `PyPluginCommonTrampoline` and
+`PyPluginInterfaceTrampoline` (`src/slic3r/plugin/PyPluginTrampoline.hpp`), and the per-type subclass
+`PyScriptPluginCapabilityTrampoline`
+(`src/slic3r/plugin/pluginTypes/script/ScriptPluginCapabilityTrampoline.hpp`), wrap the call in the
+`ORCA_PY_OVERRIDE_AUDITED` macro. For one synchronous call that macro, in order:
+
+1. constructs a `PluginCapabilityInterface::RefCounter`, which `increment()`s the capability's
+   reference count for the call's duration;
+2. constructs a `PythonGILState`, which first acquires a `PythonRuntimeLease` and then
+   `PyGILState_Ensure()`;
+3. opens a `ScopedPluginAuditContext(audit_plugin_key(), name())`;
+4. dispatches into Python via `PYBIND11_OVERRIDE`/`PYBIND11_OVERRIDE_PURE`;
+
+and unwinds those guards when the call returns.
+
+`PythonGILState` and `PythonRuntimeLease` live in `src/slic3r/plugin/PythonInterpreter.hpp`. A lease is
+a `shared_lock` on `PythonInterpreter::m_runtime_mutex`; `PythonInterpreter::shutdown()` takes the
+exclusive side, so a thread that holds a lease can safely touch Python objects, and interpreter
+finalization cannot run underneath it. `ScopedPluginAuditContext`
+(`src/slic3r/plugin/PluginAuditManager.hpp`) stores the previous thread-local plugin/capability pair
+and scoped filesystem roots, sets this call's, and restores them on destruction; the audit hook then
+attributes every filesystem/socket/process event to the plugin currently executing on that thread.
+
+### The Script capability
+
+`Slic3r::ScriptPluginCapability` (`src/slic3r/plugin/pluginTypes/script/ScriptPluginCapability.hpp`)
+declares one pure virtual method, `ExecutionResult execute()`. The async runtime invokes it through
+`invoke_script_execute` (`src/slic3r/plugin/PyPluginTrampoline.hpp`), which replicates the audited
+trampoline call (ref counter, audit scope, traceback-preserving rethrow) but returns a
+`ScriptExecuteInvocation` instead of forcing a cast:
+
+- a plain `def execute` runs to completion in `invoke_script_execute` and yields
+  `ScriptExecuteInvocation::result`;
+- an `async def execute` (or any override that returns a coroutine, detected with
+  `inspect.iscoroutine`) yields the coroutine object in `ScriptExecuteInvocation::awaitable` without
+  running it, so the runtime can drive it.
+
+`ScriptExecuteInvocation` is defined in `PyPluginTrampoline.hpp`; `py_is_coroutine` is the detection
+helper.
+
+### UI marshalling
+
+`PluginHostUi::run_on_ui_thread` (`src/slic3r/plugin/host/PluginHostUi.cpp`) forwards to the
+file-local `run_on_ui_blocking`:
+
+- if the caller is already on the wx main thread, it runs the callable inline after a
+  `py::gil_scoped_release`;
+- otherwise it sets up a `std::promise`/`std::future`, releases the GIL, posts the callable with
+  `GUI::wxGetApp().CallAfter`, and blocks on `future.get()`.
+
+That is a blocking handoff: the caller's stack is parked on a thread while the UI thread runs the
+callable. It is the correct primitive for the synchronous `update()`/`commit()` path and for
+`reload_local_bundle`/`list_bundle_ids`, but it cannot be used by an operation that must suspend.
+
+### Slicing hooks
+
+`Print::set_slicing_pipeline_hook_fn` is installed by `src/slic3r/plugin/PluginHooks.cpp`. The hook
+runs on the slicing worker thread and dispatches to `SlicingPipelinePluginCapability::execute(ctx)`
+per capability, acquiring a `PythonGILState` per capability. `SlicingPipelineContext`
+(`SlicingPipelinePluginCapability.hpp`) holds raw pointers into the live slicing graph
+(`ctx.print`, `ctx.object`) that are valid only for the duration of `execute(ctx)`. The UI thread can
+be blocked waiting on the slicing worker (`BackgroundSlicingProcess::stop()` parks it), so a
+marshalled UI call from a hook can deadlock; `PluginHostSlicing.cpp`, `SlicingPipelinePluginCapability.hpp`
+and `PluginHostUi.hpp` all document this.
+
+## Script-only async execution
+
+### Per-invocation worker and loop
+
+`ScriptAsyncRuntime` (declared in `src/slic3r/plugin/PluginManager.hpp`, implemented in
+`PluginManager.cpp`) drives every Script invocation off the caller's thread. Its `start()` creates a
+`Run` and launches a detached worker thread that runs `Impl::run_invocation`. There is one worker
+thread per invocation, so no invocation ever blocks the UI thread and no invocation is queued behind
+another plugin's.
+
+`run_invocation` runs detection and execution on the worker:
+
+- it re-checks `cancel_requested` before anything (a cancellation that arrived before the run
+  started is honored without running the plugin);
+- it calls `invoke_script_execute`; a plain `def execute` result is used directly, and an `async def`
+  coroutine is driven on a loop created for that invocation:
+  `asyncio.new_event_loop()` → `asyncio.set_event_loop(loop)` → `loop.create_task(coroutine)` →
+  `loop.run_until_complete(task)` → `loop.close()`, then `asyncio.set_event_loop(None)`.
+
+The loop is per invocation, not global, and no loop outlives its invocation. The loop for the
+calling thread is published in the thread-local `tl_script_loop` and exposed through
+`ScriptAsyncRuntime::current_loop()` (GIL held). A host call such as `begin_update()` does not suspend
+the loop: it blocks the worker thread while the UI settles, then returns a value the coroutine uses
+directly.
+
+`PluginManager::launch_script_capability` is the entry point: it resolves the capability, hands it to
+`ScriptAsyncRuntime::start`, and sets `ScriptLaunchResult::launched_async`. The completion callback
+runs on the GUI thread (or inline when there is no wx app), and `launch_script_capability` records a
+run error through `set_plugin_error` before invoking the caller's `ScriptCompletionFn`.
+`PluginManager::run_script_capability` is kept as a compatibility wrapper: it waits for the
+completion callback, pumping `wxYield()` when it is itself on the GUI thread, and returns the
+`ExecutionResult`.
+
+### Capability, runtime, GIL and audit lifetime across a suspension
+
+For the whole invocation — including an `async def` suspended at an `await` — `run_invocation` holds:
+
+- a `PluginCapabilityInterface::RefCounter` per invocation and a `shared_ptr` to the capability in the
+  `Run`, so the capability and its module stay alive across awaits and unload cannot drop them;
+- a `PythonRuntimeLease` (acquired before the GIL). `PythonInterpreter::shutdown()` cannot finalize
+  the interpreter while any invocation worker holds a lease;
+- the GIL, acquired with `pybind11::gil_scoped_acquire` on the worker;
+- a `ScopedPluginAuditContext(audit_plugin_key(), name())`, so filesystem/socket/process events
+  raised by the coroutine are attributed to the plugin.
+
+The capability reference is released inside the GIL scope (`run->capability.reset()`), because
+dropping the pybind holder from a non-Python thread would `DECREF` without the GIL. The loop is
+closed and `tl_script_loop` cleared before the worker exits.
+
+A consequence of running Script on a non-main thread: the audit permission prompt is fail-closed off
+the main thread. `request_permission` in `src/slic3r/plugin/PluginAuditManager.cpp` posts the dialog
+with `CallAfter` and denies the current event, persisting the grant when the user accepts, so a
+Script sees a denial on the first attempt and can succeed on a later one. This matches the existing
+behavior for the plugin-load worker and the slicing worker.
+
+### Blocking UI continuation
+
+`PluginHostUi::run_on_ui_thread` (in `src/slic3r/plugin/host/PluginHostUi.cpp`) is the primitive host
+calls use from the Script worker. It forwards to `run_on_ui_blocking`:
+
+- if the caller is already on the wx main thread, it runs the callable inline after a
+  `py::gil_scoped_release`;
+- otherwise it sets up a `std::promise`/`std::future`, releases the GIL, posts the callable with
+  `GUI::wxGetApp().CallAfter`, and blocks on `future.get()`.
+
+Because the Script capability owns a worker thread, blocking there does not freeze the UI. The same
+primitive is used by `begin_update()`, `set()`/`commit()`, `reload_local_bundle()` and
+`list_bundle_ids()`.
+
+### Synchronous `begin_update()`
+
+`begin_preset_update` and `begin_filament_update` (`src/slic3r/plugin/host/PluginHostPresets.cpp`) run
+on the Script worker with the GIL held and block it:
+
+1. the binding enters through `PluginHostUi::run_on_ui_thread`, which fails with a `RuntimeError`
+   before posting when there is no wx application;
+2. the UI thread runs the target binding with the GIL released — `bind_preset_target` for
+   process/printer, `bind_filament_target` for filament — including `Tab::select_preset()` and any
+   unsaved-edit prompt;
+3. the worker resumes with the name-based `PresetTransaction`, and nothing is staged until the
+   caller's later `set()`/`commit()`.
+
+An unavailable target is rejected before selection and changes no preset. A selection the user
+declines raises `RuntimeError` and creates no transaction; decisions already accepted in an earlier
+dialog are not rolled back. No GUI or preset pointer outlives the call: the transaction holds only
+copied category/name/slot values.
+
+`set()` stages a serialized value without mutating the preset, and `commit()` applies the batch
+through `Tab::apply_preset_config_values` on the UI thread. Both are synchronous and, per their
+bindings, valid only on the background Script worker.
+
+### Cancellation
+
+`ScriptAsyncRuntime::cancel_plugin(plugin_key)` sets `cancel_requested` on every active run for the
+plugin and, when a loop is live (`has_loop`), cancels the task with
+`loop.call_soon_threadsafe(task.cancel)` while holding the GIL. A synchronous `def execute`
+invocation has no loop, so only the flag is set (checked before the run starts).
+
+A task cancellation cannot interrupt a blocking `begin_update()` native call: the worker is inside
+that call, so the loop does not run the scheduled `task.cancel()` until the selection settles and the
+call returns. The transaction is therefore delivered, and any accepted UI selection stands; the
+cancellation is observed at the coroutine's next suspension point. A user-declined selection is an
+ordinary `RuntimeError`, not `asyncio.CancelledError`.
+
+A plugin's own `asyncio.CancelledError` is treated as a cancellation only when `cancel_requested` was
+set; otherwise it stays a genuine error (see `run_invocation`), so a plugin that cancels its own task
+does not masquerade as an unload cancellation.
+
+### Unload and shutdown drain
+
+Unloading or shutting down must guarantee that no plugin Python code runs after its module is
+unloaded, and that a blocking UI selection cannot mutate presets after teardown.
+
+- `PluginManager::cancel_and_wait_for_capabilities` calls `on_cancelled()` first (so the plugin can
+  observe state while the run is intact), then `ScriptAsyncRuntime::cancel_plugin`, then drains.
+  The drain is **unbounded while a Script invocation worker is outstanding** — its loop-exit
+  condition is `all_released && !invocation_active`. `has_active_run()` distinguishes a run that was
+  cancelled before it started from one whose worker is still live, and a worker blocked in
+  `begin_update()` keeps the run active until its UI callback returns. On the GUI thread the drain
+  pumps `wxYield()` so a modal selection can settle instead of being starved by the blocking wait.
+  Only the non-Script path keeps the historical bounded 2-second grace: when no invocation is active,
+  the drain stops waiting for capability references at the grace deadline and logs any remaining
+  ones.
+- `PluginManager::shutdown` detaches the libslic3r hooks (`plugin_hooks::uninstall`), stops new
+  loads, waits for in-flight loads, unloads every plugin (draining the async runs above), then calls
+  `ScriptAsyncRuntime::instance().shutdown()`, which refuses new runs and waits without a deadline
+  for every invocation worker to finish — nothing is torn down by force. `ScriptAsyncRuntime::reset()`
+  re-arms the runtime so a later `initialize()` in the same process can start runs again.
+
+Cancellation triggered by unload or shutdown is a separate, expected completion, not a plugin
+failure. `run_invocation` marks a run whose `cancel_requested` was set as `completion.cancelled` and
+clears any error, whatever the coroutine body did. `launch_script_capability` records a plugin error
+only when `!completion.cancelled && !completion.error.empty()`; `run_script_capability` reports an
+empty error for a cancelled completion; and the two GUI launchers treat `cancelled` as neither error
+nor success (the speed dial stays silent, the Plugins dialog updates no status). A plugin's own
+`CancelledError` is not counted as this expected termination unless `cancel_requested` is set, so a
+self-cancelled plugin still records its failure.
+
+## Supported and unsupported capabilities
+
+| Capability | Async support | Reason |
+| --- | --- | --- |
+| Script | `def execute` and `async def execute` both run on the per-invocation worker | The runtime owns the worker and, for a coroutine, a per-invocation loop; nothing about a Script invocation borrows C++ state. |
+| SlicingPipeline | Synchronous only | `execute(ctx)` borrows `Print`/`PrintObject` for the callback's duration, and the UI thread can be blocked on the slicing worker. `PluginHooks.cpp` rejects an async override: `cap->execute()` casts its Python result to `ExecutionResult`, and a coroutine object cannot be cast, so it surfaces as a `SlicingError` rather than being scheduled. |
+| PrinterConnection, Pages, Analysis, Importer, Exporter, Visualization, ResourceTexture | Unchanged | Not part of this bridge; they keep their existing synchronous contract. |
+
+## Deadlock constraints
+
+- **Never block the UI thread on plugin work.** Every Script launch path goes through
+  `launch_script_capability`; the speed-dial `ActionRegistry` action and the Plugins dialog launcher
+  return immediately and report the outcome later (see Examples).
+- **Never call `orca.host.ui.*` from a slicing hook.** The slicing worker runs while the UI thread
+  can be parked on it.
+- **Marshal host UI work from the Script worker only.** `PluginHostUi::run_on_ui_thread` blocks the
+  calling worker while the UI thread runs the callback; calling it from the UI thread itself would
+  deadlock the marshalling path.
+- **No pointer crosses a call boundary.** `begin_update()` returns copied category/name/slot values;
+  the `SlicingPipelineContext` graph is valid only within one synchronous `execute(ctx)`.
+
+## File and symbol map
+
+Script execution runtime:
+
+- `src/slic3r/plugin/PluginManager.hpp` / `.cpp` — `ScriptAsyncRuntime` (`instance`, `start`,
+  `cancel_plugin`, `has_active_run`, `shutdown`, `reset`, `current_loop`), `ScriptCompletion`,
+  `ScriptCompletionFn`, `ScriptLaunchResult`, `launch_script_capability`, `run_script_capability`.
+- `src/slic3r/plugin/PyPluginTrampoline.hpp` — `invoke_script_execute`, `ScriptExecuteInvocation`,
+  `py_is_coroutine`.
+- `src/slic3r/plugin/pluginTypes/script/ScriptPluginCapability.hpp` / `ScriptPluginCapabilityTrampoline.hpp`
+  — `ScriptPluginCapability::execute`, `PyScriptPluginCapabilityTrampoline`.
+
+Lifetime and GIL primitives:
+
+- `src/slic3r/plugin/PythonInterpreter.hpp` — `PythonInterpreter`, `PythonRuntimeLease`,
+  `PythonGILState`.
+- `src/slic3r/plugin/PythonPluginInterface.hpp` — `PluginCapabilityInterface`, `RefCounter`,
+  `increment`/`decrement`/`ref_count`.
+- `src/slic3r/plugin/PluginAuditManager.hpp` / `.cpp` — `ScopedPluginAuditContext`,
+  `request_filesystem_read_permissions`, `request_permission` (fail-closed off the main thread).
+
+UI marshalling:
+
+- `src/slic3r/plugin/host/PluginHostUi.hpp` / `.cpp` — `PluginHostUi::run_on_ui_thread`, the
+  file-local `run_on_ui_blocking`, and `close_windows_for_plugin`.
+- `GUI::wxGetApp().CallAfter` — the post-to-UI-thread primitive.
+
+Preset targets:
+
+- `src/slic3r/plugin/host/PluginHostPresets.cpp` — `PresetEditor`, `PresetTransaction`,
+  `bind_preset_target`, `bind_filament_target`, `begin_preset_update`, `begin_filament_update`,
+  `SelectionCancelled`, `resolve_combo_preset`/`resolve_preset_in_combo`.
+- `src/slic3r/GUI/Tab.hpp` / `.cpp` — `Tab::select_preset`, `Tab::apply_preset_config_values`,
+  `Tab::commit_preset_config_value`.
+
+Launch paths:
+
+- `src/slic3r/GUI/ActionRegistry.cpp` — `PluginScriptAction::run`, `notify_script_outcome`.
+- `src/slic3r/GUI/PluginsDialog.cpp` — `PluginsDialog::run_script_plugin_capability`.
+
+Slicing (synchronous only):
+
+- `src/slic3r/plugin/PluginHooks.cpp` — `install_slicing_pipeline_hook`.
+- `src/slic3r/plugin/pluginTypes/slicingPipeline/SlicingPipelinePluginCapability.hpp` —
+  `SlicingPipelineContext`, `execute`.
+
+Unload/shutdown:
+
+- `src/slic3r/plugin/PluginManager.cpp` — `unload_plugin`, `unload_all_plugins`,
+  `cancel_and_wait_for_capabilities`, `shutdown`.
+
+## Examples
+
+An `async def execute` that updates a preset. `execute` runs on the background Script worker with its
+own asyncio loop; `begin_update()` blocks that worker until any selection / unsaved-edit dialog is
+answered, without blocking the UI thread; `set()`/`commit()` then run synchronously on the same
+worker. This is the shape used by `sandboxes/orca_preset_transaction_demo.py`:
+
+```python
+import asyncio
+
+import orca
+
+
+class AutoTune(orca.script.ScriptPluginCapabilityBase):
+    def get_name(self):
+        return "Auto tune"
+
+    async def execute(self):
+        # begin_update() blocks this worker until the user answers any
+        # selection / unsaved-edit dialog. The UI thread stays responsive.
+        tx = orca.host.preset.process.begin_update(preset_name="0.20mm Standard")
+        tx.set("layer_height", "0.2")
+        tx.commit()
+        return orca.ExecutionResult.success("process preset updated")
+```
+
+The window-driven demo shows the same pattern where the plugin's own UI must hand work to the worker:
+`on_message` fires on the UI thread and only enqueues onto the worker loop with
+`loop.call_soon_threadsafe`; `execute` consumes that queue and calls `begin_update()` per command.
+
+Sequence for one `begin_update(...)`:
+
+```text
+Script worker (owned, per invocation)        UI thread
+  loop.run_until_complete(task)
+    begin_update()  ───────────────────────►  CallAfter(run_on_ui_blocking)
+    (blocked; not suspended)                   bind_*_target →
+                                               Tab::select_preset() … dialog
+                                               settles
+    promise set; worker resumes with PresetTransaction
+  set(); commit() (UI thread for the batch)
+  coroutine resumes at its next await
+  execute() returns ExecutionResult
+```
+
+A plain `def execute` needs no loop and runs to completion on the same worker; both kinds are
+launched with `launch_script_capability`, so the caller (UI thread) never blocks. A launch failure is
+reported inline; a started run reports its outcome through the completion callback — the speed dial
+shows "started" and pushes a completion notification, and the Plugins dialog updates its status when
+`finish` runs.
@@ -0,0 +1,99 @@
+# /// script
+# requires-python = ">=3.12"
+#
+# [tool.orcaslicer.plugin]
+# id = "preset-transaction-demo"
+# name = "Preset Transaction Demo"
+# description = "Stages several settings on one preset with begin_update()/set()/commit() (demo)."
+# author = "OrcaSlicer contributors"
+# version = "0.2.0"
+# type = "script"
+# ///
+"""Preset transaction demo: change several settings with one commit.
+
+Enable the plugin, then run "Preset Transaction Demo" from the Plugins dialog.
+Edit CATEGORY, PRESET_NAME, FILAMENT_SLOT and UPDATES below to try other presets
+and settings.
+
+``begin_update()`` resolves the target through Orca's normal preset-selection
+flow, so it may open Orca's usual "unsaved changes" dialog. The call is
+synchronous: the background Script worker waits until the user answers, while
+the UI thread stays responsive. ``set()`` only stages values; ``commit()``
+validates and applies the whole batch. The edited preset stays unsaved (dirty)
+until the user saves it through the normal preset workflow; nothing here writes
+to disk.
+
+Values are Orca's serialized config strings: numbers plain, percentages with
+"%", booleans "1"/"0", choices by their internal key, lists ";"-separated.
+"""
+
+import orca
+
+# ---------------------------------------------------------------------------
+# Edit these. CATEGORY and UPDATES belong together: each presets category only
+# accepts its own setting keys.
+# ---------------------------------------------------------------------------
+
+# Preset category: "process", "printer", or "filament".
+CATEGORY = "process"
+
+# Target preset name for process/printer. "" keeps the currently active preset.
+# For filament this optionally selects and assigns the preset for FILAMENT_SLOT;
+# "" keeps the preset the slot already has.
+PRESET_NAME = ""
+
+# 1-based filament slot. Only used when CATEGORY is "filament".
+FILAMENT_SLOT = 1
+
+# Settings staged in order, then committed together.
+UPDATES = (
+    ("layer_height", "0.25"),
+    ("wall_loops", "3"),
+)
+
+
+def _begin_update():
+    """Bind CATEGORY's target and return a transaction to stage changes on."""
+    if CATEGORY not in ("process", "printer", "filament"):
+        raise ValueError('CATEGORY must be "process", "printer", or "filament"')
+    if CATEGORY == "filament":
+        # Filament updates are addressed by their 1-based slot number.
+        return orca.host.preset.filament.begin_update(FILAMENT_SLOT, PRESET_NAME)
+    return getattr(orca.host.preset, CATEGORY).begin_update(PRESET_NAME)
+
+
+class PresetTransactionDemo(orca.script.ScriptPluginCapabilityBase):
+    def get_name(self):
+        return "Preset transaction demo"
+
+    def execute(self):
+        # A plain def runs on the background Script worker, so begin_update() may
+        # block here through Orca's selection / unsaved-edit prompts.
+        try:
+            transaction = _begin_update()
+            for key, value in UPDATES:
+                transaction.set(key, value)
+            result = transaction.commit()
+        except Exception as error:
+            return orca.ExecutionResult.failure(
+                orca.PluginResult.RecoverableError,
+                "Preset transaction demo failed: %s" % error,
+            )
+
+        return orca.ExecutionResult.success(
+            'Committed %d setting(s) to the %s preset "%s"; %s.'
+            % (
+                len(result.keys),
+                result.category,
+                result.target_name,
+                "it stays unsaved until you save it"
+                if result.dirty
+                else "it already matches its saved state",
+            )
+        )
+
+
+@orca.plugin
+class PresetTransactionDemoPackage(orca.base):
+    def register_capabilities(self):
+        orca.register_capability(PresetTransactionDemo)
@@ -0,0 +1,188 @@
+# /// script
+# requires-python = ">=3.12"
+#
+# [tool.orcaslicer.plugin]
+# id = "preset-update-demo"
+# name = "Preset Update Demo"
+# description = "Browse and edit settings in process, printer, and filament presets."
+# author = "OrcaSlicer contributors"
+# version = "0.4.0"
+# type = "script"
+# ///
+"""Interactive preset editor. Snapshots are read on the UI thread; edits run on execute's worker."""
+
+import queue
+import orca
+
+
+PAGE = r'''<!doctype html><html><head><meta charset="utf-8"><style>
+:root{color-scheme:light dark;--a:#087f78;--line:rgba(127,127,127,.25);--soft:rgba(127,127,127,.1)}
+*{box-sizing:border-box}body{margin:0;font:13px/1.45 var(--orca-font,system-ui,sans-serif);display:flex;flex-direction:column;height:100vh;color:var(--orca-fg,#20242a);background:var(--orca-bg,#fafafa)}
+header{padding:14px 18px;border-bottom:1px solid var(--line);display:flex;align-items:center;gap:12px}h1{font-size:16px;margin:0}.brand{color:var(--a);font-size:20px}select,input,textarea,button{font:inherit;color:inherit}select,input,textarea{background:var(--orca-bg,#fafafa);border:1px solid var(--line);border-radius:7px;padding:7px 9px}header select{margin-left:auto;min-width:140px}.bar{padding:10px 18px;display:flex;gap:10px;align-items:center;border-bottom:1px solid var(--line)}.bar select{min-width:220px}.bar label{font-size:11px;text-transform:uppercase;letter-spacing:.06em;opacity:.65}.badge{padding:3px 9px;border:1px solid var(--line);border-radius:20px;opacity:.7}.layout{display:grid;grid-template-columns:minmax(230px,42%) 1fr;min-height:0;flex:1}.list{border-right:1px solid var(--line);display:flex;flex-direction:column;min-height:0}.search{padding:9px;border-bottom:1px solid var(--line)}.search input{width:100%}#rows{overflow:auto;padding:4px}.row{width:100%;display:flex;gap:12px;padding:7px 9px;border:0;border-left:3px solid transparent;background:transparent;text-align:left;cursor:pointer;border-radius:3px}.row:hover,.row.sel{background:var(--soft)}.row.sel{border-left-color:var(--a)}.key{flex:1;font-family:ui-monospace,monospace;overflow:hidden;text-overflow:ellipsis}.val{max-width:45%;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;opacity:.65;font-family:ui-monospace,monospace}.editor{padding:20px;display:flex;flex-direction:column;gap:10px;overflow:auto}.editor h2{font:600 15px ui-monospace,monospace;margin:0;overflow-wrap:anywhere}.muted{opacity:.65;font-size:11px;text-transform:uppercase;letter-spacing:.06em}.current{font-family:ui-monospace,monospace;background:var(--soft);padding:10px;border-radius:7px;overflow-wrap:anywhere;white-space:pre-wrap}textarea{min-height:88px;resize:vertical;font-family:ui-monospace,monospace}.actions{display:flex;gap:8px}button.action{padding:7px 15px;border-radius:7px;border:1px solid var(--line);background:transparent;cursor:pointer}button.primary{background:var(--a);border-color:var(--a);color:white}button:disabled{opacity:.45;cursor:default}.hint{margin-top:auto;padding:10px;border-left:3px solid var(--a);background:var(--soft);border-radius:4px}.status{padding:8px 18px;border-top:1px solid var(--line);opacity:.75}.error{color:#c33}.empty{padding:20px;opacity:.65}@media(max-width:650px){.layout{grid-template-columns:1fr 1fr}.bar{flex-wrap:wrap}.bar select{min-width:120px;flex:1}}
+</style></head><body>
+<header><span class="brand">◈</span><h1>Preset editor</h1><select id="kind"><option value="process">Process</option><option value="printer">Printer</option><option value="filament">Filament</option></select><button class="action" id="close">Close</button></header>
+<div class="bar"><label id="slotlabel" hidden>Slot</label><select id="slot" hidden></select><label>Preset</label><select id="preset"></select><span class="badge" id="dirty"></span><button class="action" id="reload">Refresh</button></div>
+<div class="layout"><section class="list"><div class="search"><input id="search" placeholder="Search settings…"></div><div id="rows"></div></section><section class="editor"><div class="muted">Selected setting</div><h2 id="key">Choose a setting</h2><div class="muted">Current value</div><div class="current" id="current">—</div><label class="muted" for="value">New serialized value</label><textarea id="value" disabled></textarea><div class="actions"><button class="action primary" id="apply" disabled>Apply change</button><button class="action" id="reset" disabled>Reset</button></div><div class="hint">Choose a category, preset and filament slot. Edit any listed key, then apply. Orca may ask to switch presets or resolve unsaved changes. Values stay unsaved until saved in Orca.</div></section></div><footer class="status" id="status">Loading presets…</footer>
+<script>
+const $=id=>document.getElementById(id),S={kind:'process',slot:1,preset:'',rows:[],selected:null,busy:true,notice:'',noticeError:false};
+function send(command,extra={}){$('status').textContent='Working…';S.busy=true;controls();orca.postMessage({command,kind:S.kind,slot:S.slot,preset:$('preset').value,...extra})}
+function controls(){ $('kind').disabled=S.busy;$('slot').disabled=S.busy;$('preset').disabled=S.busy;$('apply').disabled=S.busy||!S.selected;$('reload').disabled=S.busy }
+function load(){send('state')}
+function paint(m){const notice=S.notice,noticeError=S.noticeError;S.notice='';S.noticeError=false;S.busy=false;S.kind=m.kind;S.slot=m.slot||1;S.rows=m.rows||[];S.selected=S.rows.some(r=>r.k===S.selected)?S.selected:null;
+ $('slotlabel').hidden=S.kind!=='filament';$('slot').hidden=S.kind!=='filament';$('slot').innerHTML=(m.slots||[]).map(x=>`<option value="${x.slot}">Slot ${x.slot} · ${esc(x.name||'Empty')}</option>`).join('');$('slot').value=S.slot;
+ $('preset').innerHTML=(m.presets||[]).map(x=>`<option value="${esc(x)}">${esc(x)}</option>`).join('');$('preset').value=m.preset_name||'';$('dirty').textContent=m.dirty?'Modified':'Saved';
+ const q=$('search').value.toLowerCase(),rows=S.rows.filter(r=>(r.k+' '+r.v).toLowerCase().includes(q));$('rows').innerHTML=rows.map(r=>`<button class="row ${S.selected===r.k?'sel':''}" data-key="${esc(r.k)}"><span class="key">${esc(r.k)}</span><span class="val">${esc(r.v)}</span></button>`).join('')||'<div class="empty">No matching settings</div>';
+ const r=S.rows.find(x=>x.k===S.selected);$('key').textContent=r?r.k:'Choose a setting';$('current').textContent=r?r.v:'—';$('value').disabled=!r;$('value').value=r?r.v:'';$('reset').disabled=!r;controls();$('status').textContent=m.error||notice||m.message||`${S.rows.length} settings · changes remain unsaved`;$('status').className='status'+((m.error||noticeError)?' error':'') }
+function esc(x){return String(x??'').replace(/[&<>"']/g,c=>({'&':'&amp;','<':'&lt;','>':'&gt;','"':'&quot;',"'":'&#39;'}[c]))}
+$('kind').onchange=()=>{S.kind=$('kind').value;S.selected=null;$('preset').value='';load()};$('slot').onchange=()=>{S.slot=Number($('slot').value);S.selected=null;$('preset').value='';load()};$('preset').onchange=()=>{S.selected=null;load()};$('reload').onclick=load;$('close').onclick=()=>orca.close();$('search').oninput=()=>paint({kind:S.kind,slot:S.slot,rows:S.rows,presets:[...$('preset').options].map(o=>o.value),preset_name:$('preset').value});
+$('rows').onclick=e=>{let b=e.target.closest('[data-key]');if(!b)return;S.selected=b.dataset.key;let r=S.rows.find(x=>x.k===S.selected);$('key').textContent=r.k;$('current').textContent=r.v;$('value').value=r.v;$('value').disabled=false;$('reset').disabled=false;$('apply').disabled=false;document.querySelectorAll('.row').forEach(x=>x.classList.toggle('sel',x===b))};$('reset').onclick=()=>{let r=S.rows.find(x=>x.k===S.selected);if(r)$('value').value=r.v};$('apply').onclick=()=>send('apply',{key:S.selected,value:$('value').value});orca.onMessage(m=>{if(m.command==='state')paint(m);else if(m.command==='refresh'){S.notice=m.error||m.message||'';S.noticeError=!!m.error;load()}});load();
+</script></body></html>'''
+
+
+class PresetUpdateDemo(orca.script.ScriptPluginCapabilityBase):
+    window = None
+    _commands = None
+    _cancelled = False
+
+    def get_name(self):
+        return "Preset editor demo"
+
+    def execute(self):
+        if self.window is not None and self.window.is_open():
+            return orca.ExecutionResult.success("Preset editor is already open.")
+        # The queue exists before the window so on_cancelled() can always unblock this worker, even
+        # when a forced unload destroys the window without firing on_close.
+        commands = queue.Queue()
+        self._commands = commands
+        try:
+            if self._cancelled:
+                return orca.ExecutionResult.success("Preset editor closed.")
+            self.window = orca.host.ui.create_window(
+                title="Preset editor", html=PAGE, width=900, height=620,
+                on_message=self._on_message,
+                on_close=self._on_close,
+            )
+            while True:
+                message = commands.get()
+                if self._cancelled or message.get("command") == "close":
+                    return orca.ExecutionResult.success("Preset editor closed.")
+                try:
+                    notice = {"command": "refresh", "message": self._apply(message)}
+                except Exception as error:
+                    notice = {"command": "refresh", "error": str(error)}
+                if self.window is not None and self.window.is_open():
+                    self.window.post(notice)
+        except Exception as error:
+            return orca.ExecutionResult.failure(orca.PluginResult.RecoverableError,
+                                                "Preset editor failed: %s" % error)
+        finally:
+            if self._commands is commands:
+                self._commands = None
+            self.window = None
+
+    # Both UI callbacks run on the wx main thread with the GIL held.
+    def _on_message(self, message):
+        message = dict(message) if isinstance(message, dict) else {}
+        if message.get("command") == "apply":
+            self._enqueue(message)
+            return
+        try:
+            state = self._snapshot(message)
+        except Exception as error:
+            state = {"command": "state", "kind": message.get("kind", "process"),
+                     "slot": message.get("slot", 1), "rows": [], "presets": [], "slots": [],
+                     "preset_name": "", "dirty": False, "error": str(error)}
+        window = self.window
+        if window is not None and window.is_open():
+            window.post(state)
+
+    def _on_close(self):
+        self._enqueue({"command": "close"})
+
+    def on_cancelled(self):
+        # Called before the unload drain. Enqueueing a close lets a worker parked in get() exit; a
+        # callback that arrives after the worker already left sees no queue and is harmless.
+        self._cancelled = True
+        self._enqueue({"command": "close"})
+
+    def _enqueue(self, message):
+        commands = self._commands
+        if commands is not None:
+            commands.put(message)
+
+    def _apply(self, message):
+        kind = message.get("kind", "process")
+        if kind not in ("process", "printer", "filament"):
+            raise ValueError("Unknown preset category")
+        name = message.get("preset") or ""
+        if not isinstance(name, str):
+            raise ValueError("Preset name must be a string")
+        key, value = message.get("key"), message.get("value")
+        if not isinstance(key, str) or not key or not isinstance(value, str):
+            raise ValueError("Setting key and serialized value required")
+        editor = getattr(orca.host.preset, kind)
+        if kind == "filament":
+            slot = int(message.get("slot", 1))
+            if slot < 1:
+                raise ValueError("Filament slot numbers are 1-based")
+            transaction = editor.begin_update(slot, name)
+        else:
+            transaction = editor.begin_update(name)
+        transaction.set(key, value)
+        result = transaction.commit()
+        status = "Set %s on %s. Changes remain unsaved." % (key, result.target_name)
+        if result.selection_changed:
+            status += " Orca switched the active preset."
+        if kind == "filament" and len(result.shared_slots) > 1:
+            status += " Shared by filament slots: %s." % ", ".join(str(s) for s in result.shared_slots)
+        return status
+
+    # Read-only snapshot. Runs on the UI thread so no live Preset or PresetBundle object is read
+    # from the Script worker, and never calls begin_update() or another blocking preset operation.
+    def _snapshot(self, message):
+        kind = message.get("kind", "process")
+        if kind not in ("process", "printer", "filament"):
+            raise ValueError("Unknown preset category")
+        try:
+            slot = int(message.get("slot", 1))
+        except (TypeError, ValueError):
+            slot = 1
+        requested = message.get("preset") or ""
+        if not isinstance(requested, str):
+            requested = ""
+        bundle = orca.host.preset_bundle()
+        slots = []
+        if kind == "filament":
+            assigned_names = list(bundle.current_filament_preset_names())
+            presets = list(bundle.current_filament_presets())
+            slots = [{"slot": index + 1,
+                      "name": presets[index].name if presets[index] is not None
+                              else (assigned_names[index] or None)}
+                     for index in range(len(presets))]
+            if not 1 <= slot <= len(presets):
+                slot = 1
+            preset = bundle.filaments.find_preset(requested) if requested else None
+            if preset is None and presets:
+                preset = presets[slot - 1]
+            available = list(bundle.filaments.preset_names())
+        else:
+            collection = bundle.prints if kind == "process" else bundle.printers
+            available = list(collection.preset_names())
+            preset = collection.find_preset(requested) if requested else None
+            if preset is None:
+                preset = (bundle.current_process_preset() if kind == "process"
+                          else bundle.current_printer_preset())
+        rows = []
+        if preset is not None:
+            for key in sorted(preset.config_keys()):
+                value = preset.config_value(key)
+                rows.append({"k": key, "v": "" if value is None else str(value)})
+        return {"command": "state", "kind": kind, "slot": slot, "slots": slots,
+                "presets": available, "preset_name": preset.name if preset is not None else "",
+                "dirty": bool(preset.is_dirty) if preset is not None else False, "rows": rows}
+
+
+@orca.plugin
+class PresetUpdateDemoPackage(orca.base):
+    def register_capabilities(self):
+        orca.register_capability(PresetUpdateDemo)
@@ -1126,19 +1126,6 @@ static void load_downward_settings_list_from_config(std::string config_file, std
    }
 }

-#ifdef __WXGTK__
-// Virtual GPUs (VirtualBox, VMware, QEMU) cannot back WebKit's hardware DMABUF renderer.
-static bool is_hypervisor_guest()
-{
-    std::ifstream cpuinfo("/proc/cpuinfo");
-    std::string line;
-    while (std::getline(cpuinfo, line))
-        if (boost::starts_with(line, "flags"))
-            return line.find(" hypervisor") != std::string::npos;
-    return false;
-}
-#endif
-
 int CLI::run(int argc, char **argv)
 {
    // Mark the main thread for the debugger and for runtime checks.
@@ -1189,9 +1176,6 @@ int CLI::run(int argc, char **argv)
            ::setenv("WEBKIT_FORCE_DMABUF_RENDERER", "1", /* replace */ false);
        }

-        if (is_hypervisor_guest() && WebView::SupportsForceSharedMemory())
-            ::setenv("WEBKIT_DMABUF_RENDERER_FORCE_SHM", "1", /* replace */ false);
-
        if (x11_opt_in) {
            // ===== X11 / XWayland (opted in via GDK_BACKEND=x11) =====
            BOOST_LOG_TRIVIAL(info) << "GDK_BACKEND=x11 detected; applying v2.3.2 X11/XWayland workarounds.";
@@ -3,9 +3,11 @@
 #include "GUI.hpp"
 #include "GUI_App.hpp"
 #include "I18N.hpp"
+#include "ImGuiWrapper.hpp"
 #include "MainFrame.hpp"
 #include "NativeCommands.hpp"
 #include "Notebook.hpp"
+#include "NotificationManager.hpp"
 #include "OptionsGroup.hpp"
 #include "Plater.hpp"
 #include "SettingsIndex.hpp"
@@ -99,6 +101,45 @@ std::string find_loaded_source_name(PluginManager& manager, const std::string& p
    return plugin_key;
 }

+// Translates a Script capability outcome into the action layer's result vocabulary. Shared by
+// the synchronous run path and the async completion notification.
+AppActionRunResult script_outcome_to_action_result(const ScriptCompletion& completion)
+{
+    // Cancelled by PluginManager (unload/shutdown): expected termination, nothing to show.
+    if (completion.cancelled)
+        return {};
+
+    if (!completion.error.empty())
+        return {AppActionRunResult::Level::Error, from_u8(completion.error)};
+
+    const ExecutionResult& result   = completion.result;
+    const bool             skipped  = result.status == PluginResult::Skipped;
+    const wxString         fallback = skipped ? _L("Script plugin skipped.") : _L("Script plugin finished.");
+    return {skipped ? AppActionRunResult::Level::Info : AppActionRunResult::Level::Success,
+            result.message.empty() ? fallback : from_u8(result.message)};
+}
+
+// Surfaces the eventual outcome of an async script launched from the speed dial. That launch
+// already returned (the UI was not blocked), so the finish is reported as a notification. A
+// cancellation is silent.
+void notify_script_outcome(const ScriptCompletion& completion)
+{
+    if (completion.cancelled)
+        return;
+    if (wxTheApp == nullptr || wxGetApp().is_closing())
+        return;
+
+    Plater* plater = wxGetApp().plater();
+    if (plater == nullptr || wxGetApp().imgui() == nullptr || !wxGetApp().imgui()->display_initialized())
+        return;
+
+    const AppActionRunResult action_result = script_outcome_to_action_result(completion);
+    const auto               level         = action_result.level == AppActionRunResult::Level::Error
+                                                 ? NotificationManager::NotificationLevel::ErrorNotificationLevel
+                                                 : NotificationManager::NotificationLevel::RegularNotificationLevel;
+    plater->get_notification_manager()->push_notification(NotificationType::CustomNotification, level, into_u8(action_result.message));
+}
+
 // A runnable script capability exposed as a speed-dial action. source_key = plugin_key
 // (identity), so a plugin display-name change does not re-key the action.
 struct PluginScriptAction : AppAction
@@ -124,15 +165,36 @@ struct PluginScriptAction : AppAction

    AppActionRunResult run(const std::string& /*param*/) const override
    {
-        std::string error;
-        const ExecutionResult result = PluginManager::instance().run_script_capability(plugin_key, capability, error);
-        if (!error.empty())
-            return {AppActionRunResult::Level::Error, from_u8(error)};
+        struct Outcome
+        {
+            bool               async     = false;
+            bool               completed = false;
+            AppActionRunResult result;
+        };
+        auto outcome = std::make_shared<Outcome>();

-        const bool skipped      = result.status == PluginResult::Skipped;
-        const wxString fallback = skipped ? _L("Script plugin skipped.") : _L("Script plugin finished.");
-        return {skipped ? AppActionRunResult::Level::Info : AppActionRunResult::Level::Success,
-                result.message.empty() ? fallback : from_u8(result.message)};
+        auto on_done = [outcome](const ScriptCompletion& completion) {
+            outcome->result    = script_outcome_to_action_result(completion);
+            outcome->completed = true;
+            if (outcome->async)
+                notify_script_outcome(completion);
+        };
+
+        const PluginManager::ScriptLaunchResult launch = PluginManager::instance().launch_script_capability(plugin_key, capability, on_done);
+        if (launch.launched_async) {
+            // The completion is delivered on this (GUI) thread once the (sync or async) invocation
+            // finishes, so marking `async` here cannot race with on_done. The speed dial has already
+            // shown a result by then; the final outcome arrives as a notification (a cancellation is
+            // silent).
+            outcome->async = true;
+            if (outcome->completed)
+                return outcome->result;
+            return {AppActionRunResult::Level::Info, _L("Script plugin started.")};
+        }
+
+        // The launch failed inline; on_done produced the (error) result.
+        on_done(launch.outcome);
+        return outcome->result;
    }
 };

@@ -1332,6 +1332,21 @@ boost::any ConfigOptionsGroup::get_config_value2(const DynamicPrintConfig& confi
    return ret;
 }

+bool ConfigOptionsGroup::commit_config_value(const t_config_option_key& opt_key, int opt_index)
+{
+    if (m_config == nullptr)
+        return false;
+
+    // m_opt_map is filled while the option lines are created, so it still resolves the option when
+    // the group's controls (and thus its fields) have not been built yet.
+    const std::string opt_id = option_id_in_map(m_opt_map, opt_key, opt_index);
+    if (opt_id.empty())
+        return false;
+
+    on_change_OG(opt_id, get_config_value2(*m_config, opt_key, opt_index));
+    return true;
+}
+
 Field* ConfigOptionsGroup::get_fieldc(const t_config_option_key& opt_key, int opt_index)
 {
    Field* field = get_field(opt_key);
@@ -119,6 +119,37 @@ using column_t = std::function<wxWindow*(wxWindow* parent, const Line&)>;
 using t_optionfield_map = std::map<t_config_option_key, t_field>;
 using t_opt_map = std::map< std::string, std::pair<std::string, int> >;

+// The option id a group's option map holds for opt_key, and the index it carries. `opt_index` is
+// an in/out parameter: a negative value asks for the option's single entry, an explicit one selects
+// that index. Returns an empty string when the map does not own the option, or when a negative index
+// matches several entries -- a vector option the GUI edits one index at a time, which has no single
+// value to commit. A group fills the map while its option lines are created (OptionsGroup::append_line
+// / ConfigOptionsGroup::get_option), so this resolves an option even before its controls (and its
+// field) have been built.
+inline std::string option_id_in_map(const t_opt_map& options, const t_config_option_key& opt_key, int& opt_index)
+{
+    if (opt_index >= 0) {
+        for (const auto& opt : options) {
+            if (opt.second.first == opt_key && opt.second.second == opt_index) {
+                opt_index = opt.second.second;
+                return opt.first;
+            }
+        }
+        return {};
+    }
+
+    std::string opt_id;
+    for (const auto& opt : options) {
+        if (opt.second.first != opt_key)
+            continue;
+        if (!opt_id.empty())
+            return {}; // several entries: a vector option, not one value
+        opt_id    = opt.first;
+        opt_index = opt.second.second;
+    }
+    return opt_id;
+}
+
 class OptionsGroup {
 public:
    const bool staticbox{true};
@@ -332,6 +363,15 @@ public:
 	boost::any	get_config_value(const DynamicPrintConfig& config, const std::string& opt_key, int opt_index = -1);
 	// BBS: restore all pages in preset
 	boost::any	get_config_value2(const DynamicPrintConfig& config, const std::string& opt_key, int opt_index = -1);
+	// Re-run this group's committed-change path for one of its options without a widget event:
+	// build the option's value from the config this group edits (get_config_value2, the same form
+	// the option's field reports) and dispatch on_change_OG(), so the group's option-specific
+	// conversion (e.g. the printer_agent canonicalization) and its registered change handler run
+	// exactly as for a hand edit. The option map is filled while the option lines are created, so
+	// this resolves an option whose field is not built yet (a lazy page, or an option the GUI has
+	// no field for). Returns false when this group does not own the option, or when opt_index < 0
+	// matches several entries (a vector option the GUI edits index by index has no single value).
+	bool		commit_config_value(const t_config_option_key& opt_key, int opt_index = -1);
 	Field*		get_fieldc(const t_config_option_key& opt_key, int opt_index);
 	std::pair<OG_CustomCtrl*, bool*>	get_custom_ctrl_with_blinking_ptr(const t_config_option_key& opt_key, int opt_index/* = -1*/);

@@ -21178,12 +21178,7 @@ void Plater::print_job_finished(wxCommandEvent &evt)
    Slic3r::DeviceManager* dev = Slic3r::GUI::wxGetApp().getDeviceManager();
    if (!dev) return;

-    const std::string dev_id = evt.GetString().ToStdString();
-    MachineObject* selected = dev->get_selected_machine();
-    // After a LAN print, the completion event reselects the same printer.
-    // Keep the active session while asynchronous status traffic may still be in flight.
-    if (!selected || selected->get_dev_id() != dev_id || selected->connection_type() != "lan")
-        dev->set_selected_machine(dev_id);
+    dev->set_selected_machine(evt.GetString().ToStdString());
    p->main_frame->request_select_tab(TAB_ID_MONITOR);
    // Selects the status page on a built Device tab; one built by the switch starts there.
    MonitorPanel* curr_monitor = MonitorPanel::if_built();
@@ -1158,10 +1158,7 @@ void PluginsDialog::run_script_plugin_capability(const std::string& plugin_key,
 {
    PluginManager& manager = PluginManager::instance();

-    std::string error;
-    ExecutionResult result;
-
-    auto complete_with_error = [this, &manager, &plugin_key](const std::string& plugin_error, const wxString& status_message) {
+    auto complete_with_error = [this, &manager, plugin_key](const std::string& plugin_error, const wxString& status_message) {
        const std::string normalized_error = plugin_error.empty() ? _u8L("Script plugin failed.") : plugin_error;
        if (!manager.set_plugin_error(plugin_key, normalized_error))
            BOOST_LOG_TRIVIAL(warning) << "Failed to record plugin error. plugin_key=" << plugin_key;
@@ -1177,32 +1174,53 @@ void PluginsDialog::run_script_plugin_capability(const std::string& plugin_key,
        show_status(message, "error");
    };

+    // Always runs on the GUI thread. For a started invocation (sync `def execute` or `async def`)
+    // the runtime delivers it later; it is called inline here only when the launch itself failed.
+    auto finish = [this, alive = m_alive, plugin_key, &manager, complete_with_error](const ScriptCompletion& completion) {
+        if (!alive->load())
+            return;
+
+        // Cancelled by PluginManager (unload/shutdown): expected termination. Report neither an
+        // error nor a normal success, and do not touch the plugin's error/state.
+        if (completion.cancelled)
+            return;
+
+        if (!completion.error.empty()) {
+            complete_with_error(completion.error, wxString());
+            return;
+        }
+
+        const ExecutionResult& result = completion.result;
+
+        BOOST_LOG_TRIVIAL(info) << "Script plugin execution completed. plugin_key=" << plugin_key
+                                << " status=" << static_cast<int>(result.status) << " message=" << result.message
+                                << " data=" << result.data;
+
+        const bool failed = result.status == PluginResult::RecoverableError || result.status == PluginResult::FatalError;
+        if (failed) {
+            complete_with_error(result.message, wxString());
+            return;
+        }
+
+        manager.clear_plugin_error(plugin_key);
+        send_plugins();
+
+        const bool     skipped  = result.status == PluginResult::Skipped;
+        const wxString fallback = skipped ? _L("Script plugin skipped.") : _L("Script plugin finished.");
+        const wxString message  = result.message.empty() ? fallback : from_u8(result.message);
+        show_status(message, skipped ? "info" : "success");
+    };
+
+    PluginManager::ScriptLaunchResult launch;
    {
        wxBusyCursor busy;
-        result = manager.run_script_capability(plugin_key, capability_name, error);
+        launch = manager.launch_script_capability(plugin_key, capability_name, finish);
    }

-    if (!error.empty()) {
-        complete_with_error(error, wxString());
-        return;
-    }
-
-    BOOST_LOG_TRIVIAL(info) << "Script plugin execution completed. plugin_key=" << plugin_key
-                            << " status=" << static_cast<int>(result.status) << " message=" << result.message << " data=" << result.data;
-
-    const bool failed = result.status == PluginResult::RecoverableError || result.status == PluginResult::FatalError || !error.empty();
-    if (failed) {
-        complete_with_error(result.message, wxString());
-        return;
-    }
-
-    manager.clear_plugin_error(plugin_key);
-    send_plugins();
-
-    const bool     skipped  = result.status == PluginResult::Skipped;
-    const wxString fallback = skipped ? _L("Script plugin skipped.") : _L("Script plugin finished.");
-    const wxString message  = result.message.empty() ? fallback : from_u8(result.message);
-    show_status(message, skipped ? "info" : "success");
+    // Every started invocation — a synchronous `def execute` included — completes later through
+    // `finish`; only a launch failure is reported inline. Return without blocking.
+    if (!launch.launched_async)
+        finish(launch.outcome);
 }

 void PluginsDialog::update_plugin(const std::string& plugin_key)
@@ -46,6 +46,7 @@
 #include "slic3r/GUI/DeviceCore/DevConfigUtil.h"
 #include <deque>
 #include <exception>
+#include <stdexcept>
 #include "libslic3r/LifecycleEvents.hpp"
 #include "libslic3r/Point.hpp"
 #include "slic3r/GUI/SettingsIndex.hpp"
@@ -1645,6 +1646,138 @@ void Tab::load_config(const DynamicPrintConfig& config)
    }
 }

+// The option keys a preset of `type` may hold. The tab's config shares the global
+// print_config_def with every other preset type, so membership has to be checked against the
+// preset type's own key list instead of the config definition, or a printer setting could be
+// written into the process preset.
+static const std::vector<std::string>& preset_type_options(Preset::Type type)
+{
+    static const std::vector<std::string> none;
+    switch (type) {
+    case Preset::TYPE_PRINT:    return Preset::print_options();
+    case Preset::TYPE_FILAMENT: return Preset::filament_options();
+    case Preset::TYPE_PRINTER:  return Preset::printer_options();
+    default:                    return none;
+    }
+}
+
+static const char* preset_type_name(Preset::Type type)
+{
+    switch (type) {
+    case Preset::TYPE_PRINT:    return "process";
+    case Preset::TYPE_FILAMENT: return "filament";
+    case Preset::TYPE_PRINTER:  return "printer";
+    default:                    return "preset";
+    }
+}
+
+// Commit one option whose new value already sits in m_config through the same path a hand edit
+// runs. The key-specific behaviour (ConfigOptionsGroup::on_change_OG, including the printer_agent
+// canonicalization, the group's pre-checks and Tab::on_value_change()) runs exactly as for a hand
+// edit. A built field supplies the field's typed/clamped value; otherwise the owning
+// ConfigOptionsGroup builds the value from the config it edits and dispatches the same
+// on_change_OG(). The option's page is reloaded from the config just committed first, so a built
+// field reports the committed value rather than a stale one. No tab-wide refresh happens here: the
+// caller does it once for the whole batch.
+bool Tab::commit_preset_config_value(const std::string& opt_key)
+{
+    if (Page* field_page = nullptr; Field* field = get_field(opt_key, &field_page)) {
+        field_page->reload_config();
+        field->field_changed();
+        return true;
+    }
+    for (const PageShp& page : m_pages)
+        for (const ConfigOptionsGroupShp& group : page->m_optgroups)
+            if (group->commit_config_value(opt_key))
+                return true;
+    return false;
+}
+
+// Set one option of the currently edited preset from its serialized string form, then run the
+// same update path a hand edit runs. The edited preset is not saved: it only becomes dirty,
+// exactly as if the field had been edited by hand.
+void Tab::apply_preset_config_value(const std::string& opt_key, const std::string& value)
+{
+    apply_preset_config_values({{opt_key, value}});
+}
+
+// Apply a batch of settings as one transaction: parse and validate the whole batch first, then
+// commit it through the same per-setting path apply_preset_config_value() uses, restoring the edited
+// preset and the state derived from it if a setting fails. See the header for the contract and its
+// limits.
+void Tab::apply_preset_config_values(const std::vector<std::pair<std::string, std::string>>& values)
+{
+    if (m_config == nullptr)
+        throw std::runtime_error("The preset configuration is not available");
+    if (wxGetApp().plater() == nullptr)
+        throw std::runtime_error("OrcaSlicer main window is not available");
+
+    if (values.empty())
+        return;
+
+    const std::vector<std::string>& options = preset_type_options(m_type);
+
+    // Preparation: reject every batch that cannot be applied before touching the edited preset, so a
+    // bad key or value fails without a partial write. The key must belong to this preset type, it must
+    // not repeat, and each value is strict-parsed into a scratch copy (the strict deserializer can
+    // already have mutated an option when it rejects a bad value, so the check has to run somewhere
+    // the edited preset is not affected). Callback failures cannot be prepared this way: a setting's
+    // on_change callback is a GUI method, not a pure function of the config, so whether it throws is
+    // only known by running it. That residual case is handled by the rollback below.
+    std::set<std::string>   seen;
+    DynamicPrintConfig      scratch(*m_config);
+    for (const auto& kv : values) {
+        const std::string& opt_key = kv.first;
+        if (std::find(options.begin(), options.end(), opt_key) == options.end())
+            throw std::invalid_argument(format("Unknown %1% preset setting \"%2%\"", preset_type_name(m_type), opt_key));
+        if (!seen.insert(opt_key).second)
+            throw std::invalid_argument(format("%1% preset setting \"%2%\" is set more than once in the same update",
+                                               preset_type_name(m_type), opt_key));
+        try {
+            scratch.set_deserialize_strict(opt_key, kv.second);
+        } catch (const ConfigurationError& err) {
+            throw std::invalid_argument(err.what());
+        }
+    }
+
+    // Rollback boundary: snapshot the whole edited config, not just the keys the batch names, because a
+    // key-specific callback can adjust related settings of the edited preset (mutually exclusive
+    // options, compatibility, and so on). A failure restores this config and then recomputes the state
+    // derived from it.
+    DynamicPrintConfig before(*m_config);
+    try {
+        for (const auto& kv : values) {
+            m_config->set_deserialize_strict(kv.first, kv.second);
+            if (!commit_preset_config_value(kv.first))
+                // The GUI edits this setting through a custom widget rather than a group (e.g.
+                // compatible_printers), so take the same shared no-field commit path the widget uses.
+                // The value was written above, so saved mode skips the write and keeps the path's
+                // compatibility recompute, dirty flag, preset-combo and plater updates.
+                load_key_value(kv.first, boost::any(), /*saved_value=*/true);
+        }
+    } catch (...) {
+        *m_config = before;
+        // A callback can rewrite state derived from the config (compatibility marks, the preset
+        // selector, dependent tabs, the Plater and, on the printer tab, the printer agent) before it
+        // throws. Recompute that derived state from the restored config so none of it is left
+        // reflecting the failed batch. Effects that are not a function of the config (a dialog the
+        // user already accepted, an undo snapshot, a command already sent to a device, the target
+        // selection) cannot be reversed here; see the header.
+        m_preset_bundle->update_compatible(PresetSelectCompatibleType::Never);
+        reload_config();
+        update_dirty();
+        update();
+        throw;
+    }
+
+    // Apply the batch's final state once. The commit paths above already maintained the dirty flag,
+    // preset combo and, on the printer tab, the printer-agent switch; this reloads the visible page
+    // and pushes the config to the Plater.
+    reload_config();
+    update_dirty();
+    update();
+}
+
 // Reload current $self->{config} (aka $self->{presets}->edited_preset->config) into the UI fields.
 void Tab::reload_config()
 {
@@ -424,6 +424,40 @@ public:
 	//BBS update plater presets if update_plater_presets = true
 	void			update_tab_ui(bool update_plater_presets = false);
 	void			load_config(const DynamicPrintConfig& config);
+	// Host/plugin API: set one option of this tab's currently edited preset from its serialized
+	// string value, then run the same committed-change path a field edit runs. `opt_key` must be a
+	// setting of this tab's preset type, so a key of another preset type (e.g. a printer setting
+	// passed to the process tab) is rejected instead of written silently. `value` is parsed by the
+	// strict config deserializer, which raises std::invalid_argument for an unknown key or a value
+	// the option cannot parse, and leaves the preset unchanged. The key-specific behaviour runs
+	// through its ConfigOptionsGroup::on_change_OG(): with the option's built field it uses the
+	// field's typed value, otherwise the owning group builds the value and dispatches the same call,
+	// so a not-yet-built field still gets it. A key the GUI edits through a custom widget instead
+	// takes the shared no-field commit path, Tab::load_key_value() in saved mode.
+	void			apply_preset_config_value(const std::string& opt_key, const std::string& value);
+
+	// Host/plugin API: apply a batch of settings to this tab's currently edited preset as one
+	// transaction. Each pair is a setting of this tab's preset type and its serialized string value.
+	// The whole batch is parsed and validated before the edited preset is touched; each setting then
+	// runs the same committed-change path apply_preset_config_value() uses, so setting-specific
+	// validation, correction and on_change callbacks stay authoritative. Duplicate keys are rejected,
+	// because the transaction must not resolve an incidental write order, and the batch order is
+	// preserved. If applying the batch fails, the edited preset's config is restored to its pre-batch
+	// state and the state derived from it (compatibility marks, the preset selector, dependent tabs,
+	// the Plater and the printer agent) is recomputed, so the edited preset never keeps a subset of
+	// the staged settings.
+	//
+	// Only the edited preset is restored. A setting's on_change callback is a GUI method, not a pure
+	// function of the config, so effects outside the edited preset cannot be prepared or undone: the
+	// transaction does not reverse preset/slot selection made while resolving the target, a dialog
+	// decision the user already accepted, an undo snapshot, a dependent preset's rewritten config, or
+	// anything already sent to a device. Exact all-or-nothing across those is not achievable while the
+	// authoritative GUI callbacks run; this method guarantees the edited preset's own settings, not
+	// those external effects.
+	//
+	// Throws std::invalid_argument for an unknown key, a value the option cannot parse, or a duplicate
+	// key; std::runtime_error when the preset or main window is unavailable.
+	void			apply_preset_config_values(const std::vector<std::pair<std::string, std::string>>& values);
 	virtual void	reload_config();
    void            update_mode();
    void            update_visibility();
@@ -507,6 +541,12 @@ protected:
 	wxSizer*		compatible_widget_create(wxWindow* parent, PresetDependencies &deps);
 	void 			compatible_widget_reload(PresetDependencies &deps);
 	void			load_key_value(const std::string& opt_key, const boost::any& value, bool saved_value = false);
+	// Commit one option whose new value already sits in m_config through the same path a field edit
+	// runs (throwing field, otherwise the owning group's on_change_OG()). Reloads the option's page
+	// so a built field reports the committed value, but performs no tab-wide refresh. Returns true
+	// when a built field or a group owns the option, false when the GUI edits it through a custom
+	// widget with no group entry.
+	bool			commit_preset_config_value(const std::string& opt_key);

 	//BBS: GUI refactor
 	// return true if cancelled
@@ -102,6 +102,12 @@ void install_slicing_pipeline_hook()
                        ctx.step   = step;
                        ctx.print  = &print;
                        ctx.object = object;
+                        // Slicing hooks are synchronous by design and never await: the context
+                        // borrows Print/PrintObject that are only valid during this call, and the
+                        // UI thread may itself be blocked waiting on this slicing worker. An async
+                        // override is rejected here rather than scheduled -- cap->execute() casts
+                        // its Python result to ExecutionResult and a coroutine object cannot be
+                        // cast, so it surfaces as the SlicingError below.
                        r = cap->execute(ctx);
                    } catch (const CanceledException&) {
                        throw; // cancellation must reach process(), never become a slicing error
@@ -12,11 +12,16 @@

 #include "PluginFsUtils.hpp"
 #include "PluginHooks.hpp"
+#include "PluginAuditManager.hpp"
+#include "PyPluginTrampoline.hpp"
 #include "PythonInterpreter.hpp"
 #include "PythonPluginBridge.hpp"

 #include "OrcaCloudServiceAgent.hpp"
 #include "libslic3r/Semver.hpp"
+#include "pybind11/pytypes.h"
+#include "pybind11/gil.h"
+#include "pybind11/pybind11.h"
 #include "slic3r/GUI/GUI_App.hpp"
 #include "slic3r/GUI/I18N.hpp"
 #include "slic3r/GUI/NotificationManager.hpp"
@@ -41,6 +46,7 @@
 #include <vector>
 #include <wx/app.h>
 #include <wx/thread.h>
+#include <wx/utils.h>
 #include "slic3r/GUI/ImGuiWrapper.hpp"
 #include "slic3r/GUI/Plater.hpp"

@@ -68,8 +74,10 @@ void Plugin::release_module()
 PluginManager& PluginManager::instance()
 {
    // Touch the interpreter first so its static outlives this one: ~Plugin needs it alive to
-    // release module, sys.modules, and sys.path ownership safely.
+    // release module, sys.modules, and sys.path ownership safely. Touch the async Script runtime
+    // next, so ~PluginManager can still drain it during its own shutdown().
    PythonInterpreter::instance();
+    ScriptAsyncRuntime::instance();
    static PluginManager inst;
    return inst;
 }
@@ -101,6 +109,9 @@ bool PluginManager::initialize()
        m_initialized = true;
    }

+    // Re-arm the async Script runtime in case shutdown() ran earlier in this process.
+    ScriptAsyncRuntime::instance().reset();
+
    // Bring every capability's stored config into memory. Deliberately unconditional and
    // independent of which plugins are installed: an entry outlives uninstall/unsubscribe, so a
    // plugin that comes back later finds its settings intact. A missing or malformed file just
@@ -167,6 +178,10 @@ void PluginManager::shutdown()
    unload_all_plugins();
    PythonPluginBridge::instance().clear_pending_captures();

+    // Every async Script run has been drained by unload_all_plugins above; wait for every
+    // invocation worker before the interpreter is allowed to finalize.
+    ScriptAsyncRuntime::instance().shutdown();
+
    // Every config write already goes to disk as it happens (store_capability_config), so this
    // only catches an in-memory-only mutation. Note we flush rather than clear: unloading the
    // plugins above must never discard their stored config.
@@ -754,6 +769,10 @@ void PluginManager::release_load_slot(const std::string& plugin_key)
 void PluginManager::cancel_and_wait_for_capabilities(
    const std::vector<std::shared_ptr<PluginCapabilityInterface>>& capabilities)
 {
+    // Ask the plugin to cancel first, then schedule the async cancellation: on_cancelled() can
+    // observe/record state while the run is still intact, and only afterwards is its asyncio task
+    // cancelled. Draining of capability references still follows, so the module is not unloaded
+    // until the run has settled.
    for (const auto& capability : capabilities) {
        if (!capability || !capability->is_enabled())
            continue;
@@ -769,15 +788,37 @@ void PluginManager::cancel_and_wait_for_capabilities(
        }
    }

-    const auto deadline = std::chrono::steady_clock::now() + std::chrono::seconds(2);
-    while (std::chrono::steady_clock::now() < deadline) {
+    for (const auto& capability : capabilities) {
+        if (capability)
+            ScriptAsyncRuntime::instance().cancel_plugin(capability->audit_plugin_key());
+    }
+
+    // Script rows are bounded only by their own worker: a cancelled or stalled invocation of another
+    // plugin can no longer couple to this one (each invocation owns a thread). A Script worker is
+    // drained without a deadline — forcing module unload while one is outstanding would leave Python
+    // executing against a freed module, or let a blocking preset selection mutate presets after the
+    // plugin is gone. Non-Script synchronous calls keep the historical bounded grace. On the GUI
+    // thread the event loop is pumped so a modal selection can settle instead of being starved by a
+    // blocking wait.
+    const auto grace_deadline = std::chrono::steady_clock::now() + std::chrono::seconds(2);
+    for (;;) {
        const bool all_released = std::all_of(capabilities.begin(), capabilities.end(), [](const auto& capability) {
            return !capability || capability->ref_count() == 0;
        });
-        if (all_released)
+        // A cancellation that arrived before the invocation ran skips the ref counter, so an active
+        // worker must also be gone: never unload the module while any Script thread is still live.
+        const bool invocation_active = std::any_of(capabilities.begin(), capabilities.end(), [](const auto& capability) {
+            return capability != nullptr && ScriptAsyncRuntime::instance().has_active_run(capability.get());
+        });
+        if (all_released && !invocation_active)
            return;

-        std::this_thread::sleep_for(std::chrono::milliseconds(10));
+        if (!invocation_active && std::chrono::steady_clock::now() >= grace_deadline)
+            break;
+
+        if (wxTheApp != nullptr && wxIsMainThread())
+            wxYield();
+        std::this_thread::sleep_for(std::chrono::milliseconds(5));
    }

    for (const auto& capability : capabilities) {
@@ -2070,41 +2111,385 @@ bool PluginManager::delete_and_unsubscribe_cloud_plugin(const std::string& plugi
    return finalize_cloud_plugin_removal(descriptor, false, error);
 }

+// ── Async Script runtime ────────────────────────────────────────────────────────────────────
+
+namespace {
+
+// The asyncio loop of the Script invocation running on the calling thread. Owned +1 while set;
+// always cleared under the GIL before the worker thread exits.
+thread_local PyObject* tl_script_loop = nullptr;
+
+} // namespace
+
+struct ScriptAsyncRuntime::Impl
+{
+    struct Run
+    {
+        std::string plugin_key;
+        std::string capability_name;
+        std::shared_ptr<PluginCapabilityInterface> capability;
+        std::function<void(const ScriptCompletion&)> on_done;
+        std::atomic<bool> cancel_requested{false};
+        // True while an asyncio loop/task is live for this run. Read without the GIL by
+        // cancel_plugin() to avoid taking the GIL for a purely synchronous invocation.
+        std::atomic<bool> has_loop{false};
+
+        // Live asyncio loop/task for cancellation. Guarded by handle_mutex and only touched
+        // with the GIL held.
+        std::mutex       handle_mutex;
+        pybind11::object loop;
+        pybind11::object task;
+    };
+
+    std::mutex                        mutex;
+    std::condition_variable           cv;
+    std::vector<std::shared_ptr<Run>> active;
+    bool                              stopping = false;
+
+    // Runs one invocation to completion on the calling (worker) thread.
+    void run_invocation(const std::shared_ptr<Run>& run);
+};
+
+void ScriptAsyncRuntime::Impl::run_invocation(const std::shared_ptr<Run>& run)
+{
+    ScriptCompletion completion;
+
+    {
+        PythonRuntimeLease lease = PythonInterpreter::instance().acquire_runtime_lease();
+        if (!lease) {
+            completion.error = _u8L("Python interpreter is shutting down");
+        } else {
+            pybind11::gil_scoped_acquire gil;
+
+            if (run->cancel_requested.load(std::memory_order_acquire)) {
+                // Cancelled before it ran: expected termination, never an error.
+                completion.cancelled = true;
+            } else {
+                // Hold the capability reference, the audit scope and the GIL for the whole
+                // invocation, so unload/shutdown cannot tear the module out from under it.
+                PluginCapabilityInterface::RefCounter ref_counter(*run->capability);
+
+                std::optional<ScopedPluginAuditContext> audit_scope;
+                if (!run->capability->audit_plugin_key().empty())
+                    audit_scope.emplace(run->capability->audit_plugin_key(), run->capability->name());
+
+                // Detection and execution both happen here, on the worker: a synchronous
+                // `def execute` runs to completion off the UI thread, exactly like an `async def`.
+                ScriptExecuteInvocation invocation = invoke_script_execute(run->capability);
+                if (!invocation.error.empty()) {
+                    completion.error = invocation.error;
+                } else if (!invocation.is_async) {
+                    completion.result = invocation.result;
+                } else if (run->cancel_requested.load(std::memory_order_acquire)) {
+                    completion.cancelled = true;
+                } else {
+                    try {
+                        pybind11::module_ asyncio = pybind11::module_::import("asyncio");
+                        pybind11::object  loop    = asyncio.attr("new_event_loop")();
+                        asyncio.attr("set_event_loop")(loop);
+
+                        tl_script_loop = loop.ptr();
+                        Py_INCREF(tl_script_loop);
+
+                        pybind11::object task = loop.attr("create_task")(std::move(invocation.awaitable));
+                        {
+                            std::lock_guard<std::mutex> lock(run->handle_mutex);
+                            run->loop = loop;
+                            run->task = task;
+                        }
+                        run->has_loop.store(true, std::memory_order_release);
+                        // A cancellation that arrived before the loop came up must still land.
+                        if (run->cancel_requested.load(std::memory_order_acquire))
+                            loop.attr("call_soon_threadsafe")(task.attr("cancel"));
+
+                        try {
+                            pybind11::object returned = loop.attr("run_until_complete")(task);
+                            completion.result = returned.cast<ExecutionResult>();
+                        } catch (pybind11::error_already_set& err) {
+                            // Only our own cancel_plugin() cancellation is expected termination; a
+                            // CancelledError the plugin raised on its own stays a real error.
+                            if (err.matches(asyncio.attr("CancelledError")) &&
+                                run->cancel_requested.load(std::memory_order_acquire)) {
+                                completion.cancelled = true;
+                            } else {
+                                log_python_exception_keep(err);
+                                completion.error = err.what();
+                            }
+                        }
+
+                        run->has_loop.store(false, std::memory_order_release);
+                        {
+                            std::lock_guard<std::mutex> lock(run->handle_mutex);
+                            run->task = pybind11::object();
+                            run->loop = pybind11::object();
+                        }
+                        Py_CLEAR(tl_script_loop);
+                        loop.attr("close")();
+                        asyncio.attr("set_event_loop")(pybind11::none());
+                    } catch (pybind11::error_already_set& err) {
+                        log_python_exception_keep(err);
+                        completion.error = err.what();
+                    } catch (const std::exception& ex) {
+                        completion.error = ex.what();
+                    }
+
+                    // Covers an exception thrown after the loop came up but before the clear above.
+                    if (run->has_loop.load(std::memory_order_acquire)) {
+                        run->has_loop.store(false, std::memory_order_release);
+                        std::lock_guard<std::mutex> lock(run->handle_mutex);
+                        run->task = pybind11::object();
+                        run->loop = pybind11::object();
+                    }
+
+                    if (tl_script_loop != nullptr)
+                        Py_CLEAR(tl_script_loop);
+                }
+            }
+
+            // Drop the capability reference while the GIL is held: releasing a pybind holder from
+            // a non-Python thread would DECREF the capability without the GIL. Runs on every
+            // lease-valid path, including an invocation cancelled before it ran.
+            run->capability.reset();
+        }
+    }
+
+    // A cancellation requested by cancel_plugin() (unload/shutdown) is expected termination and is
+    // authoritative: whatever the body did — finished, swallowed CancelledError, or failed — nothing
+    // is surfaced as an error or as a normal success.
+    if (run->cancel_requested.load(std::memory_order_acquire)) {
+        completion.cancelled = true;
+        completion.error.clear();
+    }
+
+    auto on_done = std::move(run->on_done);
+    auto deliver = [on_done, completion]() {
+        if (on_done)
+            on_done(completion);
+    };
+
+    if (wxTheApp == nullptr || wxIsMainThread())
+        deliver();
+    else
+        GUI::wxGetApp().CallAfter(deliver);
+
+    // Leave `active` last, so a drain cannot observe the run as finished before its completion was
+    // queued/delivered and its capability reference released.
+    {
+        std::lock_guard<std::mutex> lock(mutex);
+        active.erase(std::remove(active.begin(), active.end(), run), active.end());
+    }
+    cv.notify_all();
+}
+
+ScriptAsyncRuntime& ScriptAsyncRuntime::instance()
+{
+    static ScriptAsyncRuntime inst;
+    return inst;
+}
+
+ScriptAsyncRuntime::ScriptAsyncRuntime() : m_impl(std::make_unique<Impl>()) {}
+
+ScriptAsyncRuntime::~ScriptAsyncRuntime() { shutdown(); }
+
+bool ScriptAsyncRuntime::start(const std::string& plugin_key,
+                               const std::string& capability_name,
+                               std::shared_ptr<PluginCapabilityInterface> capability,
+                               std::function<void(const ScriptCompletion&)> on_done)
+{
+    if (!PythonInterpreter::instance().is_initialized())
+        return false;
+
+    auto run             = std::make_shared<Impl::Run>();
+    run->plugin_key      = plugin_key;
+    run->capability_name = capability_name;
+    run->capability      = std::move(capability);
+    run->on_done         = std::move(on_done);
+
+    {
+        std::lock_guard<std::mutex> lock(m_impl->mutex);
+        if (m_impl->stopping)
+            return false;
+        m_impl->active.push_back(run);
+    }
+
+    // One worker thread per invocation. A stalled invocation of one plugin can never delay another
+    // plugin's unload or another invocation, and no invocation body ever runs on the caller (UI)
+    // thread. The thread holds `run` (and so the capability) until it finishes; the runtime tracks
+    // it in `active` and waits for it on shutdown.
+    Impl* impl = m_impl.get();
+    try {
+        std::thread([impl, run] { impl->run_invocation(run); }).detach();
+    } catch (...) {
+        std::lock_guard<std::mutex> lock(m_impl->mutex);
+        m_impl->active.erase(std::remove(m_impl->active.begin(), m_impl->active.end(), run), m_impl->active.end());
+        return false;
+    }
+    return true;
+}
+
+void ScriptAsyncRuntime::cancel_plugin(const std::string& plugin_key)
+{
+    std::vector<std::shared_ptr<Impl::Run>> runs;
+    {
+        std::lock_guard<std::mutex> lock(m_impl->mutex);
+        for (const auto& run : m_impl->active)
+            if (run->plugin_key == plugin_key)
+                runs.push_back(run);
+    }
+
+    for (const auto& run : runs)
+        run->cancel_requested.store(true, std::memory_order_release);
+
+    for (const auto& run : runs) {
+        // A synchronous invocation has no loop to cancel; skip it so the caller never blocks on
+        // the GIL while that invocation is (uninterruptibly) running.
+        if (!run->has_loop.load(std::memory_order_acquire))
+            continue;
+
+        PythonGILState gil;
+        if (!gil)
+            continue;
+
+        pybind11::object loop;
+        pybind11::object task;
+        {
+            std::lock_guard<std::mutex> lock(run->handle_mutex);
+            loop = run->loop;
+            task = run->task;
+        }
+        if (!loop || !task)
+            continue;
+
+        try {
+            loop.attr("call_soon_threadsafe")(task.attr("cancel"));
+        } catch (const std::exception& ex) {
+            BOOST_LOG_TRIVIAL(warning) << "Script async cancel failed for plugin '" << plugin_key << "': " << ex.what();
+        }
+    }
+}
+
+bool ScriptAsyncRuntime::has_active_run(const PluginCapabilityInterface* capability) const
+{
+    std::lock_guard<std::mutex> lock(m_impl->mutex);
+    for (const auto& run : m_impl->active)
+        if (run->capability.get() == capability)
+            return true;
+    return false;
+}
+
+void ScriptAsyncRuntime::shutdown()
+{
+    {
+        std::lock_guard<std::mutex> lock(m_impl->mutex);
+        m_impl->stopping = true;
+    }
+
+    std::unique_lock<std::mutex> lock(m_impl->mutex);
+    m_impl->cv.wait(lock, [this] { return m_impl->active.empty(); });
+}
+
+void ScriptAsyncRuntime::reset()
+{
+    shutdown();
+
+    std::lock_guard<std::mutex> lock(m_impl->mutex);
+    m_impl->stopping = false;
+}
+
+pybind11::object ScriptAsyncRuntime::current_loop()
+{
+    if (tl_script_loop == nullptr)
+        return pybind11::object();
+    return pybind11::reinterpret_borrow<pybind11::object>(pybind11::handle(tl_script_loop));
+}
+
 ExecutionResult PluginManager::run_script_capability(const std::string& plugin_key, const std::string& capability_name, std::string& error)
 {
-    if (plugin_key.empty() || capability_name.empty()) {
-        return {};
+    ExecutionResult result;
+    std::mutex              mutex;
+    std::condition_variable cv;
+    bool                    done = false;
+
+    ScriptLaunchResult launch = launch_script_capability(
+        plugin_key, capability_name, [&](const ScriptCompletion& completion) {
+            std::lock_guard<std::mutex> lock(mutex);
+            result = completion.result;
+            // A cancel_plugin() cancellation is expected termination, not an error to report.
+            error  = completion.cancelled ? std::string() : completion.error;
+            done   = true;
+            cv.notify_all();
+        });
+
+    if (launch.launched_async) {
+        // Async run: the completion is delivered on the GUI thread. When this call is itself on
+        // the GUI thread it must pump the event loop, or the completion can never be delivered.
+        std::unique_lock<std::mutex> lock(mutex);
+        if (wxTheApp != nullptr && wxIsMainThread()) {
+            while (!done) {
+                cv.wait_for(lock, std::chrono::milliseconds(10));
+                lock.unlock();
+                wxYield();
+                lock.lock();
+            }
+        } else {
+            cv.wait(lock, [&] { return done; });
+        }
+    } else {
+        result = launch.outcome.result;
+        error  = launch.outcome.error;
+    }
+
+    return result;
+}
+
+PluginManager::ScriptLaunchResult PluginManager::launch_script_capability(const std::string& plugin_key,
+                                                                          const std::string& capability_name,
+                                                                          ScriptCompletionFn  on_done)
+{
+    ScriptLaunchResult launch;
+
+    // Mirror the historical synchronous behavior for a dangling reference: nothing to run and
+    // no error (the caller's guarded UI normally prevents this).
+    if (plugin_key.empty() || capability_name.empty())
+        return launch;
+
+    if (m_shutting_down.load(std::memory_order_acquire)) {
+        launch.outcome.error = _u8L("Plugin system is shutting down.");
+        return launch;
    }

    auto cap = get_plugin_capability({PluginCapabilityType::Script, capability_name, plugin_key});
    if (!cap)
-        return {};
+        return launch;

-    auto cap_interface = std::dynamic_pointer_cast<ScriptPluginCapability>(cap);
-    if (!cap_interface)
-        return {};
+    if (!std::dynamic_pointer_cast<ScriptPluginCapability>(cap))
+        return launch;

-    ExecutionResult result;
-    try {
-        PythonGILState gil;
-        if (!gil) {
-            error = "Python interpreter is shutting down";
-            return {};
-        }
-        result = cap_interface->execute();
-    } catch (const std::exception& ex) {
-        error = ex.what();
-        BOOST_LOG_TRIVIAL(error) << "Script plugin execution threw exception. plugin_key=" << plugin_key << " error=" << error;
-    } catch (...) {
-        error = _u8L("Unknown error");
-        BOOST_LOG_TRIVIAL(error) << "Script plugin execution threw unknown exception. plugin_key=" << plugin_key;
+    // Every Script body runs off the caller's thread now: the invocation — including detection and
+    // a synchronous `def execute` — is handed to the runtime, which runs it on its own worker and
+    // reports the outcome through the completion callback. Nothing executes before returning here,
+    // so the UI thread is never blocked by a Script invocation.
+    const bool started = ScriptAsyncRuntime::instance().start(
+        plugin_key, capability_name, cap,
+        [this, plugin_key, on_done](const ScriptCompletion& completion) {
+            // A cancellation requested by cancel_plugin() (unload/shutdown) is expected termination:
+            // record no plugin error and surface nothing. Genuine user/plugin errors still record.
+            if (!completion.cancelled && !completion.error.empty())
+                set_plugin_error(plugin_key, completion.error);
+            if (on_done)
+                on_done(completion);
+        });
+
+    if (!started) {
+        launch.outcome.error = _u8L("Plugin system is shutting down.");
+        set_plugin_error(plugin_key, launch.outcome.error);
+        BOOST_LOG_TRIVIAL(error) << "Script plugin execution failed. plugin_key=" << plugin_key
+                                 << " error=" << launch.outcome.error;
+        return launch;
    }

-    if (!error.empty()) {
-        set_plugin_error(plugin_key, error);
-    }
-
-    return result;
+    launch.launched_async = true;
+    return launch;
 }

 void PluginManager::dispatch_lifecycle_event(LifecycleEvent evt, const LifecycleEventContext& ctx) {
@@ -15,6 +15,7 @@
 #include <memory>
 #include <mutex>
 #include <optional>
+#include "pybind11/pytypes.h"
 #include "slic3r/plugin/PluginFsUtils.hpp"
 #include <slic3r/plugin/PythonPluginInterface.hpp>
 #include <string>
@@ -98,6 +99,19 @@ struct Plugin
    void release_module();
 };

+// Outcome of one Script invocation, delivered to a script completion callback.
+//
+// `cancelled` marks a run terminated by PluginManager's own cancellation (plugin unload / shutdown):
+// expected termination, not a failure. Callers must not surface it as an error nor as a normal
+// success. `error` carries only genuine user/plugin exceptions; `result` is meaningful when neither
+// `cancelled` nor a non-empty `error` is set.
+struct ScriptCompletion
+{
+    ExecutionResult result;
+    std::string     error;
+    bool            cancelled = false;
+};
+
 class PluginManager
 {
 public:
@@ -214,6 +228,25 @@ public:

    ExecutionResult run_script_capability(const std::string& plugin_key, const std::string& capability_name, std::string& error);

+    // Outcome of launching a Script capability.
+    struct ScriptLaunchResult
+    {
+        bool             launched_async = false; // true => a run started off-thread; wait for on_done
+        ScriptCompletion outcome;                // meaningful when !launched_async (start failure only)
+    };
+    // Invoked on the GUI thread when a Script invocation finishes (or inline, on the calling thread,
+    // when the run could not be started at all).
+    using ScriptCompletionFn = std::function<void(const ScriptCompletion&)>;
+
+    // Starts a Script capability off the caller's thread. Both a synchronous `def execute` and an
+    // `async def execute` run on a ScriptAsyncRuntime worker, so this never blocks the UI thread and
+    // no invocation runs before returning. `launched_async` is true exactly when a run started; the
+    // caller then waits for on_done instead of a returned result. When it is false, `outcome.error`
+    // explains why (the caller's guarded UI normally prevents this).
+    ScriptLaunchResult launch_script_capability(const std::string& plugin_key,
+                                                const std::string& capability_name,
+                                                ScriptCompletionFn on_done = {});
+
    void dispatch_lifecycle_event(LifecycleEvent evt, const LifecycleEventContext& ctx);

 private:
@@ -309,6 +342,74 @@ private:
    std::atomic<bool> m_shutting_down{false};
 };

+// ── Async Script execution ──────────────────────────────────────────────────────────────────
+//
+// A Script capability whose Python `execute` is an `async def` (or otherwise returns a
+// coroutine) must not run on the UI thread, and cannot use the synchronous trampoline path,
+// which casts the return value to ExecutionResult and would reject a coroutine.
+//
+// ScriptAsyncRuntime drives such executions off the calling (UI) thread. Each invocation gets its
+// own worker thread and, for an `async def`, its own asyncio event loop. Every invocation body —
+// detection, a synchronous `def execute`, or an `async def` coroutine — runs on that worker, so no
+// Script invocation ever blocks the UI thread and no invocation is queued behind another plugin's.
+// For the whole invocation the worker holds:
+//   * a shared_ptr to the capability, so the capability and its module stay alive across awaits;
+//   * a PythonRuntimeLease plus the GIL, so the interpreter cannot finalize underneath it;
+//   * the capability's audit scope (ScopedPluginAuditContext),
+// which keeps plugin unload and interpreter shutdown from tearing the module out from under a
+// suspended run. Unload cancels the run and drains it (it never force-unloads after a timeout).
+//
+// Interface for host awaitables (see plugin/host/): a host awaitable is constructed inside the
+// Script coroutine, i.e. on the worker thread with that invocation's loop running, so it can
+// read that loop with asyncio.get_running_loop() or ScriptAsyncRuntime::current_loop(). To
+// resume from another thread (typically the UI thread) it must resolve its future with
+// loop.call_soon_threadsafe(...) and must never touch plugin Python objects, or the loop,
+// directly from that other thread. The loop only runs while the coroutine is suspended inside
+// run_until_complete; once Script execute returns the loop is closed and the module may unload.
+class ScriptAsyncRuntime
+{
+public:
+    static ScriptAsyncRuntime& instance();
+
+    ~ScriptAsyncRuntime();
+    ScriptAsyncRuntime(const ScriptAsyncRuntime&)            = delete;
+    ScriptAsyncRuntime& operator=(const ScriptAsyncRuntime&) = delete;
+
+    // Starts one Script invocation on its own worker thread. The invocation body (Python `execute`,
+    // whether `def` or `async def`) and its detection both run on that worker, never on the calling
+    // thread. `on_done` is invoked on the GUI thread (or inline when there is no wx app) when the
+    // invocation finishes; a `cancelled` completion is expected termination from cancel_plugin().
+    // Returns false when the runtime is shutting down.
+    bool start(const std::string& plugin_key,
+               const std::string& capability_name,
+               std::shared_ptr<PluginCapabilityInterface> capability,
+               std::function<void(const ScriptCompletion&)> on_done);
+
+    // Requests cancellation of every active run owned by plugin_key: marks the run and cancels
+    // its asyncio task via loop.call_soon_threadsafe (a synchronous invocation has no loop).
+    void cancel_plugin(const std::string& plugin_key);
+
+    // True while a run for `capability` is active.
+    bool has_active_run(const PluginCapabilityInterface* capability) const;
+
+    // Stops accepting runs and waits for every in-flight invocation worker. Nothing is torn down
+    // by force.
+    void shutdown();
+
+    // Re-arms the runtime after a shutdown() so a later initialize() in the same process can
+    // start runs again.
+    void reset();
+
+    // The asyncio loop of the Script invocation running on the calling thread, or an empty
+    // object when the calling thread is not running one. Must be called with the GIL held.
+    static pybind11::object current_loop();
+
+private:
+    ScriptAsyncRuntime();
+    struct Impl;
+    std::unique_ptr<Impl> m_impl;
+};
+
 // Resolve each configured capability reference to a loaded capability of type T and run `execute`.
 template<typename T>
 void execute_capabilities_from_refs(const ConfigOptionStrings& capabilities,
@@ -2,10 +2,12 @@
 #define slic3r_PyPluginTrampoline_hpp_

 #include "libslic3r/LifecycleEvents.hpp"
+#include <exception>
 #include <pybind11/embed.h>

 #include <boost/log/trivial.hpp>

+#include <memory>
 #include <optional>
 #include <stdexcept>
 #include <string>
@@ -14,9 +16,11 @@
 #include "PythonInterpreter.hpp"
 #include "PluginFsUtils.hpp"
 #include "PluginAuditManager.hpp"
+#include "pybind11/cast.h"
 #include <pybind11/pybind11.h>
 #include <pybind11/gil.h>
 #include <pybind11/pytypes.h>
+#include <utility>

 // Trampoline variants of pybind11's override macros. Every C++->Python plugin call crosses a
 // trampoline method, so this single boundary is where we (1) log the full Python traceback and
@@ -61,6 +65,78 @@
    } while (0)

 namespace Slic3r {
+
+// True when `object` is a coroutine object (the value produced by calling an `async def`).
+// Match inspect.iscoroutine() without importing Python modules inside the plugin audit scope.
+// Must be called with the GIL held.
+inline bool py_is_coroutine(const pybind11::handle& object)
+{
+    return object && PyCoro_CheckExact(object.ptr());
+}
+
+// Result of invoking a Script capability's Python `execute` exactly once.
+//
+// A synchronous override (`def execute`) runs to completion here and yields `result`.
+// An asynchronous override (`async def execute`, or any override that returns a coroutine)
+// yields the coroutine object in `awaitable` WITHOUT running it: the cast to ExecutionResult
+// that the trampoline would otherwise perform is impossible for a coroutine, so the caller
+// chooses how to drive it. Whoever drives it must keep the capability referenced and re-open
+// this call's GIL + runtime lease + audit scope for the coroutine's whole lifetime (see
+// ScriptAsyncRuntime in PluginManager.hpp).
+struct ScriptExecuteInvocation
+{
+    bool             is_async = false;
+    pybind11::object awaitable; // valid iff is_async; a coroutine object created under the GIL
+    ExecutionResult  result;    // valid iff !is_async
+    std::string      error;     // non-empty when the call or coroutine creation raised
+};
+
+// Invokes ScriptPluginCapability::execute() under the GIL, replicating the audited trampoline
+// call (capability ref counter, audit scope, traceback-preserving rethrow) but returning a
+// coroutine object instead of forcing a cast when the plugin's `execute` is `async def`.
+//
+// `capability` must be the concrete, Python-bound capability instance (obtainable from
+// get_plugin_capability()); it is resolved back to its Python object through pybind's instance
+// map. Never throws: a Python exception is logged (full traceback) and reported in `error`.
+inline ScriptExecuteInvocation invoke_script_execute(const std::shared_ptr<PluginCapabilityInterface>& capability)
+{
+    ScriptExecuteInvocation invocation;
+    if (!capability)
+        return invocation;
+
+    try {
+        pybind11::gil_scoped_acquire gil;
+        PluginCapabilityInterface::RefCounter ref_counter(*capability);
+
+        std::optional<ScopedPluginAuditContext> audit_scope;
+        if (const std::string& audit_key = capability->audit_plugin_key(); !audit_key.empty())
+            audit_scope.emplace(audit_key, capability->name());
+
+        pybind11::object py_capability = pybind11::cast(capability);
+        pybind11::object returned      = py_capability.attr("execute")();
+
+        if (py_is_coroutine(returned)) {
+            invocation.is_async = true;
+            invocation.awaitable = std::move(returned);
+            return invocation;
+        }
+
+        invocation.result = returned.cast<ExecutionResult>();
+    } catch (pybind11::error_already_set& err) {
+        const bool audit_denial = PluginAuditManager::instance().audit_denial_pending();
+        if (audit_denial)
+            PluginAuditManager::instance().clear_current_plugin();
+        invocation.error = err.what();
+        log_python_exception_keep(err);
+        if (audit_denial)
+            PluginAuditManager::instance().clear_audit_denial();
+    } catch (const std::exception& ex) {
+        invocation.error = ex.what();
+    }
+
+    return invocation;
+}
+
 template<class Base> class PyPluginCommonTrampoline : public Base
 {
 public:
@@ -2,6 +2,7 @@
 #include "PluginHostUi.hpp"
 #include "slic3r/plugin/PluginBindingUtils.hpp"

+#include <memory>
 #include <pybind11/pytypes.h>
 #include <pybind11/cast.h>
 #include <pybind11/pybind11.h>
@@ -11,18 +12,21 @@
 #include <libslic3r/Preset.hpp>
 #include <libslic3r/PresetBundle.hpp>

-#include <memory>
-
 #include <slic3r/GUI/GUI.hpp>
 #include <slic3r/GUI/GUI_App.hpp>
 #include <slic3r/GUI/MainFrame.hpp>
 #include <slic3r/GUI/Plater.hpp>
+#include <slic3r/GUI/PresetComboBoxes.hpp> // TabPresetComboBox::set_filament_idx
 #include <slic3r/GUI/Tab.hpp>

 #include <pybind11/stl.h>

+#include <wx/string.h>
+
+#include <set>
 #include <stdexcept>
 #include <string>
+#include <utility>
 #include <vector>

 namespace py = pybind11;
@@ -48,6 +52,543 @@ PresetCollection& printer_presets(PresetBundle& bundle)
    return static_cast<PresetCollection&>(bundle.printers);
 }

+// Handle to one category of currently edited preset. It is a category, not a snapshot: it always
+// resolves the preset the matching tab edits now, so it stays valid across preset switches.
+struct PresetEditor
+{
+    Preset::Type type = Preset::TYPE_INVALID;
+};
+
+const char* preset_tab_name(Preset::Type type)
+{
+    switch (type) {
+    case Preset::TYPE_PRINT:    return "process";
+    case Preset::TYPE_FILAMENT: return "filament";
+    case Preset::TYPE_PRINTER:  return "printer";
+    default:                    return "preset";
+    }
+}
+
+PresetCollection& collection_for(PresetBundle& bundle, Preset::Type type)
+{
+    switch (type) {
+    case Preset::TYPE_PRINT:    return bundle.prints;
+    case Preset::TYPE_FILAMENT: return bundle.filaments;
+    case Preset::TYPE_PRINTER:  return printer_presets(bundle);
+    default:                    throw std::invalid_argument("Unsupported preset category");
+    }
+}
+
+// Marker for a user-declined selection: Tab::select_preset() returned false. It derives from
+// std::runtime_error (pybind11 maps the base to RuntimeError), so callers see it as an ordinary
+// failed transaction and no staged setting or slot assignment is created.
+struct SelectionCancelled : std::runtime_error
+{
+    using std::runtime_error::runtime_error;
+};
+
+// --------------------------------------------------------------------------
+// The staged preset update lifecycle described in docs/HLSD/preset-plugin-api.md.
+//
+// begin_update() resolves and binds one target (selecting it through the normal UI flow when
+// the caller asked for a preset that is not already active), returns a PresetTransaction that
+// stages changes with set(), and applies them only on commit(). The transaction holds names,
+// never preset pointers, so it stays valid across reloads; a target or filament slot that changed
+// between begin_update() and commit() is rejected instead of silently editing the new mapping.
+//
+// begin_update() is synchronous: it runs on the background Script worker, marshals the target
+// selection to the UI thread with PluginHostUi::run_on_ui_thread(), and blocks that worker until
+// the selection and any unsaved-edit dialog settle. The UI thread stays responsive because the
+// Script capability owns its worker thread. No GUI or preset pointer outlives the call; the
+// returned transaction holds copied category/name/slot values. The update() shorthand shares the
+// same target resolution and is safe only from that worker, never from the UI thread or a slicing
+// pipeline hook.
+//
+// Known limits of this implementation, kept explicit rather than hidden:
+//   * A requested preset_name is resolved by the exact name its dropdown entry shows: the item's
+//     display label or its stored item alias (the internal preset name). A name two entries carry
+//     is rejected as ambiguous instead of being resolved by position. Process and printer resolve
+//     against the tab dropdown; a filament preset_name resolves against the requested slot's own
+//     sidebar selector, not the tab's, so its compatibility filter is the one that applies. A
+//     target the selector does not offer fails before the flow's unsaved-edit prompt. The flow
+//     itself is unchanged and the target is still confirmed as the edited preset afterwards.
+//   * A filament preset_name that names a different preset for a slot selects it through
+//     Tab::select_preset() (the normal flow, honouring unsaved-edit prompts) and then updates the
+//     slot mapping with PresetBundle::set_filament_preset() plus every dependent side effect the
+//     sidebar selection path performs: the project-dirty/selection refresh, the dynamic filament
+//     list, the slot's own combo (re-run so it lists and selects the assigned target), the
+//     conditional support-filament flushing recalc and the slot's AMS sync badge (read from the
+//     slot combo's own flag). The private Plater::priv::on_select_preset() path cannot be reused
+//     from here, so this mirrors its filament branch rather than calling it.
+//   * A user-declined selection does not undo decisions the user already accepted in an earlier
+//     dialog. It aborts before any slot assignment or transaction is created, so no staged
+//     setting is applied.
+// --------------------------------------------------------------------------
+
+// Outcome of one committed transaction. Identifies the target, whether selecting it switched
+// anything, and for filament (whose preset may be shared) which slots share the edited preset.
+struct PresetUpdateResult
+{
+    Preset::Type             type                    = Preset::TYPE_INVALID;
+    std::string              target_name;
+    bool                     selection_changed       = false;
+    int                      slot_number             = -1; // 1-based for filament, -1 otherwise
+    bool                     slot_assignment_changed = false;
+    std::vector<int>         shared_slots;
+    std::vector<std::string> keys;
+    bool                     dirty                   = false;
+};
+
+struct PresetTransaction
+{
+    Preset::Type  type                    = Preset::TYPE_INVALID;
+    std::string   target_name;
+    bool          filament                = false;
+    int           slot_number             = 0; // 1-based, filament only
+    std::string   slot_assignment_snapshot;    // slot's assigned preset as of begin_update()
+    bool          selection_changed       = false;
+    bool          slot_assignment_changed = false;
+
+    std::vector<std::pair<std::string, std::string>> staged;
+    std::set<std::string>                            staged_keys;
+    bool                                             committed = false;
+
+    void               set(const std::string& key, const std::string& value);
+    PresetUpdateResult commit();
+};
+
+GUI::GUI_App& require_gui_app()
+{
+    GUI::GUI_App& app = GUI::wxGetApp();
+    if (app.is_closing())
+        throw std::runtime_error("OrcaSlicer is closing");
+    if (app.preset_bundle == nullptr)
+        throw std::runtime_error("Preset bundle is not available");
+    if (app.plater() == nullptr)
+        throw std::runtime_error("OrcaSlicer main window is not available");
+    return app;
+}
+
+GUI::Tab* require_tab(GUI::GUI_App& app, Preset::Type type)
+{
+    GUI::Tab* tab = app.get_tab(type);
+    if (tab == nullptr)
+        throw std::runtime_error(std::string("The ") + preset_tab_name(type) + " preset tab is not available");
+    // The tab for this preset type exists, but the selected printer's technology may not use it
+    // (the print tab no-ops under SLA); refuse instead of writing a value the UI cannot apply.
+    if (!tab->supports_printer_technology(app.preset_bundle->printers.get_selected_preset().printer_technology()))
+        throw std::runtime_error(std::string("The ") + preset_tab_name(type)
+                                 + " preset is not available for the selected printer technology");
+    return tab;
+}
+
+// True for a combo row that is a group header, a marker or a disabled row: it carries a marker in
+// its client data and is not a selectable preset.
+bool combo_item_is_marker(GUI::PresetComboBox& combo, int item)
+{
+    const auto marker = reinterpret_cast<std::size_t>(combo.GetClientData(item));
+    return marker >= GUI::PresetComboBox::LABEL_ITEM_DISABLED && marker < GUI::PresetComboBox::LABEL_ITEM_MAX;
+}
+
+// How a caller-supplied name resolved against a combo's actual items.
+struct ComboPresetMatch
+{
+    int         item          = -1;    // first matching item, or -1
+    bool        ambiguous     = false; // two distinct items carry this name
+    std::string internal_name;         // internal preset name of the match (empty when none)
+};
+
+// Resolve `requested` by the name each combo item shows: its display label, or its stored item
+// alias (the internal preset name, or the printer model for a system printer preset). Names are
+// compared with the modified-dirty suffix removed, i.e. exactly what the dropdown shows. Reading
+// the combo's own items means this respects the combo's real selectable model (visibility, its
+// show-incompatible state and, for a slot combo, that slot's compatibility). A name that two
+// distinct items carry is reported ambiguous instead of being resolved by position.
+ComboPresetMatch resolve_combo_preset(GUI::PresetComboBox& combo, const std::string& requested)
+{
+    ComboPresetMatch  match;
+    const std::string want       = Preset::remove_suffix_modified(requested);
+    const int         item_count = combo.GetCount();
+    for (int item = 0; item < item_count; ++item) {
+        if (combo_item_is_marker(combo, item))
+            continue;
+        const wxString    alias      = combo.GetItemAlias(item);
+        const std::string alias_name = alias.empty() ? std::string()
+                                                     : Preset::remove_suffix_modified(alias.ToUTF8().data());
+        const std::string label_name = Preset::remove_suffix_modified(combo.GetString(item).ToUTF8().data());
+        if ((alias_name.empty() || alias_name != want) && label_name != want)
+            continue;
+        if (match.item >= 0 && match.item != item) {
+            match.ambiguous = true;
+            return match;
+        }
+        match.item          = item;
+        match.internal_name = alias_name.empty() ? label_name : alias_name;
+    }
+    return match;
+}
+
+// Index of the item whose internal name is `preset_name`, or -1. Used for per-item flags (the AMS
+// sync badge); the internal name is unique, so no ambiguity handling is needed here.
+int combo_item_for_preset(GUI::PresetComboBox& combo, const std::string& preset_name)
+{
+    const std::string want       = Preset::remove_suffix_modified(preset_name);
+    const int         item_count = combo.GetCount();
+    for (int item = 0; item < item_count; ++item) {
+        if (combo_item_is_marker(combo, item))
+            continue;
+        const wxString    alias = combo.GetItemAlias(item);
+        const std::string alias_name = alias.empty() ? std::string()
+                                                     : Preset::remove_suffix_modified(alias.ToUTF8().data());
+        if (!alias_name.empty() && alias_name == want)
+            return item;
+    }
+    return -1;
+}
+
+// Resolve `requested` to the internal preset name its dropdown entry names, or throw. `category`
+// and `selector` are used only for the error text. A name the selector does not offer, or that two
+// entries share, raises std::invalid_argument.
+std::string resolve_preset_in_combo(GUI::PresetComboBox& combo, const std::string& requested,
+                                    const std::string& category, const std::string& selector)
+{
+    const ComboPresetMatch match = resolve_combo_preset(combo, requested);
+    if (match.ambiguous)
+        throw std::invalid_argument("The " + category + " name \"" + requested + "\" is ambiguous in the " + selector
+                                    + "; more than one entry shows it, so name the preset by its own entry");
+    if (match.item < 0)
+        throw std::invalid_argument("The " + category + " preset \"" + requested + "\" is not offered by the " + selector);
+    return match.internal_name;
+}
+
+// The preset a filament slot currently resolves to, by its internal name. A slot whose stored
+// name is empty or does not resolve yields an error identifying the slot.
+std::string resolved_slot_preset(PresetBundle& bundle, int slot_number)
+{
+    if (slot_number < 1 || static_cast<size_t>(slot_number) > bundle.filament_presets.size())
+        throw std::out_of_range("Filament slot " + std::to_string(slot_number)
+                                + " is out of range; slot numbers are 1-based and this printer has "
+                                + std::to_string(bundle.filament_presets.size()) + " filament slot(s)");
+    const std::string& assigned_name = bundle.filament_presets[static_cast<size_t>(slot_number) - 1];
+    if (assigned_name.empty())
+        throw std::runtime_error("Filament slot " + std::to_string(slot_number) + " has no assigned filament preset");
+    Preset* preset = bundle.filaments.find_preset(assigned_name);
+    if (preset == nullptr)
+        throw std::runtime_error("Filament slot " + std::to_string(slot_number) + " is assigned \"" + assigned_name
+                                 + "\", which does not resolve to a filament preset");
+    return preset->name;
+}
+
+void PresetTransaction::set(const std::string& key, const std::string& value)
+{
+    if (committed)
+        throw std::runtime_error("This preset transaction has already been committed; start a new begin_update()");
+    if (key.empty())
+        throw std::invalid_argument("A setting key is required");
+    // Conflicting duplicate writes to one setting are rejected rather than resolved by order.
+    if (!staged_keys.insert(key).second)
+        throw std::invalid_argument("Setting \"" + key + "\" is already staged in this transaction; "
+                                    "conflicting duplicate writes to one setting are rejected");
+    staged.emplace_back(key, value);
+}
+
+PresetUpdateResult PresetTransaction::commit()
+{
+    if (committed)
+        throw std::runtime_error("This preset transaction has already been committed; start a new begin_update()");
+    if (type == Preset::TYPE_INVALID)
+        throw std::runtime_error("This preset transaction has no target");
+
+    PresetUpdateResult result;
+    PluginHostUi::run_on_ui_thread([&] {
+        GUI::GUI_App&     app        = require_gui_app();
+        GUI::Tab*         tab        = require_tab(app, type);
+        PresetBundle&     bundle     = *app.preset_bundle;
+        PresetCollection& collection = collection_for(bundle, type);
+
+        // The target must still be the edited preset: the user may have switched away while the
+        // transaction was staged, and editing a different preset would break "explicit target".
+        const std::string edited = collection.get_edited_preset().name;
+        if (edited != target_name)
+            throw std::runtime_error("The edited " + std::string(preset_tab_name(type)) + " preset is \"" + edited
+                                     + "\", not this transaction's target \"" + target_name
+                                     + "\"; nothing was applied");
+
+        if (filament) {
+            // Reject a stale slot mapping instead of editing whatever the slot now points at.
+            const std::string now_assigned = resolved_slot_preset(bundle, slot_number);
+            if (now_assigned != slot_assignment_snapshot)
+                throw std::runtime_error("Filament slot " + std::to_string(slot_number) + " now holds \"" + now_assigned
+                                         + "\", not \"" + slot_assignment_snapshot
+                                         + "\" as when this transaction was created; the slot mapping changed, so nothing was applied");
+        }
+
+        // Apply the whole batch through the tab's batch path: it validates every key and value before
+        // touching the preset, rejects duplicate keys, runs the same per-setting commit path a hand
+        // edit uses (validation, on_change, dirty state) and refreshes once for the batch. A failure
+        // restores the edited preset, so no staged setting survives a failed commit.
+        tab->apply_preset_config_values(staged);
+
+        result.type                    = type;
+        result.target_name             = target_name;
+        result.selection_changed       = selection_changed;
+        result.slot_number             = filament ? slot_number : -1;
+        result.slot_assignment_changed = slot_assignment_changed;
+        result.keys.reserve(staged.size());
+        for (const auto& entry : staged)
+            result.keys.push_back(entry.first);
+        result.dirty = collection.get_edited_preset().is_dirty;
+
+        if (filament) {
+            // Every slot whose assigned preset resolves to the edited one is affected: the preset
+            // is shared, not a per-slot override.
+            for (std::size_t index = 0; index < bundle.filament_presets.size(); ++index) {
+                Preset* preset = bundle.filaments.find_preset(bundle.filament_presets[index]);
+                if (preset != nullptr && preset->name == target_name)
+                    result.shared_slots.push_back(static_cast<int>(index) + 1);
+            }
+        }
+    });
+
+    committed = true;
+    return result;
+}
+
+// Process/printer target resolution: the active preset when no name is given, otherwise the named
+// preset selected through the normal tab-selection flow (which enforces the dropdown/compatibility
+// rules and the unsaved-edit prompt). Binds only after confirming the requested preset is edited.
+// Runs on the UI thread with the GIL released, called from begin_preset_update().
+void bind_preset_target(Preset::Type type, const std::string& preset_name, PresetTransaction& transaction)
+{
+    GUI::GUI_App&     app        = require_gui_app();
+    GUI::Tab*         tab        = require_tab(app, type);
+    PresetCollection& collection = collection_for(*app.preset_bundle, type);
+
+    const std::string current = collection.get_edited_preset().name;
+    std::string       target  = current;
+    bool              selection_changed = false;
+
+    if (!preset_name.empty()) {
+        // Resolve by the name the tab's dropdown actually shows (display label or item alias), so a
+        // plugin can pass exactly what the user sees. With no populated dropdown there is nothing
+        // to resolve against, so fall back to collection internal names.
+        GUI::TabPresetComboBox* combo = tab->get_combo_box();
+        std::string             resolved;
+        if (combo != nullptr && combo->GetCount() > 0)
+            resolved = resolve_preset_in_combo(*combo, preset_name, preset_tab_name(type),
+                                               "preset selector for the selected printer");
+        else
+            resolved = preset_name;
+
+        Preset* requested = collection.find_preset(resolved);
+        if (requested == nullptr)
+            throw std::invalid_argument("No " + std::string(preset_tab_name(type)) + " preset named \"" + resolved
+                                        + "\" is available to select");
+        target = requested->name;
+        if (target != current) {
+            // Normal UI selection: honours the unsaved-edit prompt; a declined prompt returns false
+            // and is a user cancellation, distinct from any other resolution failure.
+            if (!tab->select_preset(target))
+                throw SelectionCancelled("Switching the edited " + std::string(preset_tab_name(type)) + " preset to \""
+                                         + target + "\" was canceled; nothing was staged");
+            selection_changed = true;
+        }
+    }
+
+    // select_preset() can still leave a different preset edited (e.g. the target is not an
+    // allowed dropdown choice), so confirm before binding.
+    if (collection.get_edited_preset().name != target)
+        throw std::runtime_error("The edited " + std::string(preset_tab_name(type)) + " preset is \""
+                                 + collection.get_edited_preset().name + "\", not \"" + target
+                                 + "\"; the transaction was not created");
+
+    transaction.type              = type;
+    transaction.target_name       = target;
+    transaction.selection_changed = selection_changed;
+}
+
+// Blocking form used by begin_update() and update().
+PresetTransaction begin_preset_update(Preset::Type type, const std::string& preset_name)
+{
+    PresetTransaction transaction;
+    PluginHostUi::run_on_ui_thread([&] { bind_preset_target(type, preset_name, transaction); });
+    return transaction;
+}
+
+// Filament target resolution: slot_number identifies the slot; an omitted preset_name keeps the
+// preset assigned to it. A supplied preset_name selects that preset for the slot through the normal
+// tab-selection flow, then records the slot assignment and its dependent Plater side effects (the
+// ones the sidebar selection path performs) only after that flow succeeds, so a canceled prompt
+// changes neither. A mixed-color virtual slot is rejected before any of this, with or without a
+// preset_name. A requested preset the requested slot's own dropdown does not offer is rejected
+// before the selection flow, so no dialog is raised for it; the one exception is the slot's own
+// current assignment, which stays targetable when the dropdown hides it. A different preset the
+// tab happens to edit is a globally edited target, not an offered choice for this slot, and is
+// rejected.
+// Runs on the UI thread with the GIL released, called from begin_filament_update().
+void bind_filament_target(int slot_number, const std::string& preset_name, PresetTransaction& transaction)
+{
+    GUI::GUI_App& app    = require_gui_app();
+    PresetBundle& bundle = *app.preset_bundle;
+    GUI::Plater*  plater = app.plater();
+
+    // A mixed-color virtual slot has no single filament preset behind it, so every form of this
+    // call is rejected: with or without a preset_name there is no one preset to edit or assign.
+    // Range-guarded so an out-of-range slot still gets resolved_slot_preset()'s clear error.
+    if (slot_number >= 1 && static_cast<size_t>(slot_number) <= bundle.filament_presets.size()
+        && bundle.is_mixed_filament(static_cast<size_t>(slot_number) - 1))
+        throw std::invalid_argument("Filament slot " + std::to_string(slot_number)
+                                    + " is a mixed-color virtual slot; it has no single filament preset to edit or assign");
+
+    // Resolve and validate before any selection, so a bad slot fails without a prompt.
+    const std::string assigned_internal = resolved_slot_preset(bundle, slot_number);
+
+    GUI::Tab* tab = require_tab(app, Preset::TYPE_FILAMENT);
+
+    const size_t slot_index = static_cast<size_t>(slot_number) - 1;
+
+    std::string target = assigned_internal;
+    if (!preset_name.empty()) {
+        // Resolve against the requested sidebar slot's own selector, not the tab's: that is the
+        // model the user picks this slot's filament from, including its compatibility filter. The
+        // selector matches the exact name shown (display label or item alias).
+        std::vector<GUI::PlaterPresetComboBox*>& slot_combos = plater->sidebar().combos_filament();
+        GUI::PlaterPresetComboBox* slot_combo = slot_index < slot_combos.size() ? slot_combos[slot_index] : nullptr;
+        std::string                resolved;
+        if (slot_combo != nullptr && slot_combo->GetCount() > 0) {
+            const ComboPresetMatch match = resolve_combo_preset(*slot_combo, preset_name);
+            if (match.ambiguous)
+                throw std::invalid_argument("The filament name \"" + preset_name
+                                            + "\" is ambiguous in the filament preset selector for filament slot "
+                                            + std::to_string(slot_number)
+                                            + "; more than one entry shows it, so name the preset by its own entry");
+            if (match.item >= 0) {
+                resolved = match.internal_name;
+            } else {
+                // Not shown by this slot's selector. Only the slot's current assignment stays
+                // targetable (a hidden or incompatible-but-selected preset the dropdown omits);
+                // resolve it by internal name or by display alias and accept only that preset. A
+                // different preset the tab happens to edit is a globally edited target, not an
+                // offered choice for this slot, and is rejected.
+                Preset* by_name = bundle.filaments.find_preset(preset_name);
+                if (by_name == nullptr) {
+                    const std::string& alias_name = bundle.filaments.get_preset_name_by_alias(preset_name);
+                    by_name                       = bundle.filaments.find_preset(alias_name);
+                }
+                if (by_name == nullptr || by_name->name != assigned_internal)
+                    throw std::invalid_argument("Filament preset \"" + preset_name
+                                                + "\" is not offered by the filament preset selector for filament slot "
+                                                + std::to_string(slot_number));
+                resolved = by_name->name;
+            }
+        } else {
+            // The slot selector is not populated; fall back to the tab selector, then to collection
+            // internal names, so the call still works when the sidebar has not been laid out.
+            GUI::TabPresetComboBox* tab_combo = tab->get_combo_box();
+            if (tab_combo != nullptr && tab_combo->GetCount() > 0)
+                resolved = resolve_preset_in_combo(*tab_combo, preset_name, "filament",
+                                                   "filament preset selector for the selected printer");
+            else
+                resolved = preset_name;
+        }
+
+        Preset* requested = bundle.filaments.find_preset(resolved);
+        if (requested == nullptr)
+            throw std::invalid_argument("No filament preset named \"" + resolved + "\" is available to select");
+        target = requested->name;
+    }
+
+    bool selection_changed = false;
+    if (bundle.filaments.get_edited_preset().name != target) {
+        // A declined prompt is a user cancellation: it is thrown before any slot-assignment change,
+        // so neither the mapping nor a setting is touched.
+        if (!tab->select_preset(target))
+            throw SelectionCancelled("Switching the edited filament preset to \"" + target + "\" for filament slot "
+                                     + std::to_string(slot_number)
+                                     + " was canceled; neither the slot assignment nor any setting was changed");
+        if (bundle.filaments.get_edited_preset().name != target)
+            throw std::runtime_error("The edited filament preset is \"" + bundle.filaments.get_edited_preset().name
+                                     + "\", not \"" + target + "\"; the transaction was not created");
+        selection_changed = true;
+    }
+
+    bool assignment_changed = false;
+    if (!preset_name.empty() && target != assigned_internal) {
+        if (app.app_config == nullptr)
+            throw std::runtime_error("Application configuration is not available");
+        // Mirror the filament branch of Plater::priv::on_select_preset() (the sidebar's normal
+        // preset selection): update the mapping, then every dependent project/UI side effect,
+        // rather than the vector entry alone.
+        const bool was_support = GUI::is_support_filament(static_cast<int>(slot_index));
+        bundle.set_filament_preset(slot_index, target);
+        plater->update_project_dirty_from_presets();
+        bundle.export_selections(*app.app_config);
+        plater->sidebar().update_dynamic_filament_list();
+        // Assigning a support filament (or moving away from one) changes which filaments the
+        // flush rules apply to, so the normal flow recalculates the flushing volumes when
+        // auto-calc covers every filament.
+        if (GUI::is_support_filament(static_cast<int>(slot_index)) != was_support
+            && app.app_config->get("auto_calculate_flush") == "all")
+            plater->sidebar().auto_calc_flushing_volumes(static_cast<int>(slot_index));
+        // Refresh the requested slot's own sidebar combo so its list and current selection show the
+        // newly assigned target (the list may not have contained it), matching the sidebar
+        // selection path. Fetch the pointer after update_dynamic_filament_list(), which may
+        // rebuild the combo vector.
+        std::vector<GUI::PlaterPresetComboBox*>& slot_combos = plater->sidebar().combos_filament();
+        if (slot_index < slot_combos.size() && slot_combos[slot_index] != nullptr) {
+            GUI::PlaterPresetComboBox* slot_combo = slot_combos[slot_index];
+            slot_combo->update();
+            // Keep the slot's AMS sync badge truthful, reading the item's own flag, the same source
+            // on_select_preset() reads, so no UI state is invented here.
+            const int item = combo_item_for_preset(*slot_combo, target);
+            if (item >= 0)
+                slot_combo->set_sync_badge(slot_combo->GetFlag(item)
+                                           == static_cast<int>(GUI::PresetComboBox::FilamentAMSType::FROM_AMS));
+        }
+        plater->on_filament_change(slot_index);
+        assignment_changed = true;
+    }
+
+    // Match PlaterPresetComboBox::switch_to_tab(): record which 0-based filament slot this tab
+    // combobox now edits, so the GUI shows the slot the value was written for.
+    if (GUI::TabPresetComboBox* combo = tab->get_combo_box())
+        combo->set_filament_idx(slot_number - 1);
+
+    transaction.type                     = Preset::TYPE_FILAMENT;
+    transaction.filament                 = true;
+    transaction.slot_number              = slot_number;
+    transaction.target_name              = target;
+    transaction.selection_changed        = selection_changed;
+    transaction.slot_assignment_changed  = assignment_changed;
+    // Snapshot the mapping after the explicit assignment, as the slot's resolved internal name,
+    // so commit() compares like with like (a stored alias resolves to the same internal preset).
+    transaction.slot_assignment_snapshot = resolved_slot_preset(bundle, slot_number);
+}
+
+// Blocking form used by begin_update() and update().
+PresetTransaction begin_filament_update(int slot_number, const std::string& preset_name)
+{
+    PresetTransaction transaction;
+    PluginHostUi::run_on_ui_thread([&] { bind_filament_target(slot_number, preset_name, transaction); });
+    return transaction;
+}
+
+// Compatibility shorthand: one staged setting, committed immediately through the same
+// begin_update()/set()/commit() path, so targeting, selection, validation and commit are shared.
+void update_edited_preset(Preset::Type type, const std::string& key, const std::string& value)
+{
+    PresetTransaction transaction = begin_preset_update(type, std::string());
+    transaction.set(key, value);
+    transaction.commit();
+}
+
+void update_filament_slot(int slot_number, const std::string& key, const std::string& value)
+{
+    PresetTransaction transaction = begin_filament_update(slot_number, std::string());
+    transaction.set(key, value);
+    transaction.commit();
+}
+
 void reload_local_bundle(const std::string& bundle_id)
 {
    bool        reloaded = false;
@@ -100,7 +641,7 @@ std::vector<std::string> list_bundle_ids()

 void host_bindings::register_presets(py::module_& host)
 {
-    auto preset = host.def_submodule("preset", "Preset operations");
+    auto preset  = host.def_submodule("preset", "Preset operations");
    auto bundles = preset.def_submodule("bundles", "Local preset bundle operations");
    bundles.def("reload_local", &reload_local_bundle, py::arg("bundle_id"),
                "Reload one local preset bundle from the active user's _local directory.");
@@ -119,6 +660,145 @@ void host_bindings::register_presets(py::module_& host)
        .value("Plate", Preset::TYPE_PLATE)
        .value("Model", Preset::TYPE_MODEL);

+    py::class_<PresetUpdateResult>(preset, "PresetUpdateResult",
+                                   "Outcome of one committed preset transaction. target_name is the preset that was "
+                                   "edited; selection_changed says whether begin_update() switched the active preset; "
+                                   "for filament, slot_number is the 1-based target slot, slot_assignment_changed "
+                                   "says whether selecting the requested preset reassigned that slot, and shared_slots "
+                                   "lists every 1-based slot whose assigned preset is the edited (shared) one. keys "
+                                   "lists the settings applied, in order, and dirty says whether the edited preset "
+                                   "now differs from its saved state.")
+        .def_readonly("type", &PresetUpdateResult::type)
+        .def_readonly("target_name", &PresetUpdateResult::target_name)
+        .def_readonly("selection_changed", &PresetUpdateResult::selection_changed)
+        .def_readonly("slot_number", &PresetUpdateResult::slot_number)
+        .def_readonly("slot_assignment_changed", &PresetUpdateResult::slot_assignment_changed)
+        .def_readonly("shared_slots", &PresetUpdateResult::shared_slots)
+        .def_readonly("keys", &PresetUpdateResult::keys)
+        .def_readonly("dirty", &PresetUpdateResult::dirty)
+        .def_property_readonly("category", [](const PresetUpdateResult& result) { return preset_tab_name(result.type); })
+        .def("__repr__", [](const PresetUpdateResult& result) {
+            return std::string("<PresetUpdateResult ") + preset_tab_name(result.type) + " \"" + result.target_name
+                   + "\" keys=" + std::to_string(result.keys.size()) + ">";
+        });
+
+    py::class_<PresetTransaction>(preset, "PresetTransaction",
+                                  "A staged, single-target preset edit returned by begin_update(). set() stages a "
+                                  "serialized value without mutating the preset; commit() validates and applies the "
+                                  "whole batch through the normal setting-change path. begin_update() blocks the "
+                                  "background Script worker until any selection or unsaved-edit dialog is answered, "
+                                  "while the UI thread stays responsive; set() and commit() run synchronously on the "
+                                  "same worker. Nothing is saved to disk: the edited preset stays dirty until the user "
+                                  "saves it.")
+        .def_readonly("type", &PresetTransaction::type)
+        .def_readonly("target_name", &PresetTransaction::target_name)
+        .def_readonly("selection_changed", &PresetTransaction::selection_changed)
+        .def_property_readonly("slot_number", [](const PresetTransaction& transaction) {
+            return transaction.filament ? transaction.slot_number : -1;
+        })
+        .def_property_readonly("category", [](const PresetTransaction& transaction) { return preset_tab_name(transaction.type); })
+        .def_property_readonly("staged_keys", [](const PresetTransaction& transaction) {
+            std::vector<std::string> keys;
+            keys.reserve(transaction.staged.size());
+            for (const auto& entry : transaction.staged)
+                keys.push_back(entry.first);
+            return keys;
+        })
+        .def("set", &PresetTransaction::set, py::arg("key"), py::arg("value"),
+             "Stage one setting change. key must be a setting of the target preset category and value its "
+             "serialized string form; staging validates neither, so commit() is where an invalid key or value "
+             "fails. Staging the same key twice in one transaction raises ValueError (conflicting duplicate "
+             "writes are rejected). After commit() the transaction is closed.")
+        .def("commit", &PresetTransaction::commit,
+             "Validate and apply every staged setting through the same path as editing it in the GUI, then return "
+             "a PresetUpdateResult. An invalid key or value raises ValueError; a changed target or filament slot "
+             "mapping raises RuntimeError; a failure leaves none of the staged settings applied. The edited preset "
+             "becomes dirty until the user saves it.");
+
+    py::class_<PresetEditor>(preset, "PresetEditor",
+                             "Handle to a category of currently edited preset. It is not a snapshot: it always "
+                             "resolves the preset the matching tab edits now, so it stays usable across preset "
+                             "switches. update() edits the preset in place; the change is not saved to disk.")
+        .def_readonly("type", &PresetEditor::type)
+        .def(
+            "begin_update",
+            [](const PresetEditor& editor, const std::string& preset_name) {
+                if (editor.type == Preset::TYPE_FILAMENT)
+                    throw std::invalid_argument("begin_update on the filament editor takes "
+                                                "(slot_number, preset_name=\"\"); use orca.host.preset.filament.begin_update(slot_number, ...)");
+                return begin_preset_update(editor.type, preset_name);
+            },
+            py::arg("preset_name") = "",
+            "Resolve and bind this category's target preset and return a PresetTransaction. With no preset_name the "
+            "currently active preset is targeted; a preset_name must be a preset this category can select, and is "
+            "selected through the normal preset-selection flow (which prompts about unsaved edits). The call blocks "
+            "the background Script worker until any such dialog is answered, leaving the UI thread responsive. A "
+            "selection the user cancels raises RuntimeError; an unavailable or invalid target raises ValueError. "
+            "Either failure creates no transaction and stages no setting. Call it from the background Script worker, "
+            "never from the UI thread. This form is for process and printer; filament takes "
+            "begin_update(slot_number, preset_name=\"\").")
+        .def(
+            "begin_update",
+            [](const PresetEditor& editor, int slot_number, const std::string& preset_name) {
+                if (editor.type != Preset::TYPE_FILAMENT)
+                    throw std::invalid_argument("The slot_number form of begin_update() is only available on "
+                                                "orca.host.preset.filament; call begin_update(preset_name=\"\") on this editor");
+                return begin_filament_update(slot_number, preset_name);
+            },
+            py::arg("slot_number"), py::arg("preset_name") = "",
+            "Resolve and bind a filament preset by 1-based slot and return a PresetTransaction. Omitting preset_name "
+            "targets the preset assigned to the slot; supplying a different name selects it for the slot through the "
+            "normal flow (prompting about unsaved edits) and, once that succeeds, records the new slot assignment with "
+            "the same Plater side effects the sidebar selection performs (project/selection refresh, dynamic filament "
+            "list, conditional support-filament flushing recalc and the slot's AMS sync badge). A requested preset "
+            "this slot's dropdown does not offer is rejected before that flow, so it raises no prompt; the slot's own "
+            "current assignment stays targetable even when the dropdown hides it. A selection the user cancels raises "
+            "RuntimeError and changes neither the slot assignment nor any setting. An out-of-range, empty or "
+            "unresolved slot is rejected, and a mixed-color virtual slot is rejected whether or not preset_name is "
+            "given. The transaction edits the shared preset, so every slot assigned to it is affected. The call "
+            "blocks the background Script worker until the selection settles, leaving the UI thread responsive; call "
+            "it from that worker, never from the UI thread.")
+        .def(
+            "update",
+            [](const PresetEditor& editor, const std::string& key, const std::string& value) {
+                update_edited_preset(editor.type, key, value);
+            },
+            py::arg("key"), py::arg("value"),
+            "Set one setting of the currently edited preset and run the same committed-change path as "
+            "editing the setting in the GUI; the edited preset becomes dirty until saved/exported. "
+            "key must be a setting of this preset category and value its serialized string form, "
+            "otherwise ValueError is raised and nothing is written. A setting edited through a field "
+            "runs that field's validation even before its page has been opened; one the GUI edits "
+            "outside a field (such as compatible printers) also recomputes preset compatibility. "
+            "Equivalent to begin_update() with the active preset as target, then set(key, value) "
+            "and commit(); like begin_update() this call blocks the background Script worker.")
+        .def(
+            "update",
+            [](const PresetEditor& editor, int slot_number, const std::string& key, const std::string& value) {
+                if (editor.type != Preset::TYPE_FILAMENT)
+                    throw std::invalid_argument("The slot_number form of update() is only available on "
+                                                "orca.host.preset.filament; call update(key, value) on this editor");
+                update_filament_slot(slot_number, key, value);
+            },
+            py::arg("slot_number"), py::arg("key"), py::arg("value"),
+            "Set one setting of the filament preset assigned to a 1-based filament slot. When that preset "
+            "is not the one currently edited the call switches to it through the normal preset-selection "
+            "flow, so an unsaved edited preset still prompts the user and a declined prompt cancels the "
+            "call with an error and no change. An out-of-range, empty or unresolved slot is rejected with "
+            "a clear error, as is a mixed-color virtual slot, which has no single preset to edit. Other "
+            "preset editors accept only update(key, value); this form raises "
+            "ValueError on them. Equivalent to begin_update(slot_number) with an omitted preset_name "
+            "(the slot's current assignment is kept), then set(key, value) and commit(); like "
+            "begin_update() this call blocks the background Script worker.");
+
+    // The three preset categories edited by the main tabs. `process` is the print/process preset,
+    // `printer` the machine preset and `filament` the currently edited filament preset (its
+    // 3-argument form addresses a 1-based filament slot); each only accepts its own settings, so a
+    // printer setting passed to `process` is rejected instead of written silently.
+    preset.attr("process")  = py::cast(PresetEditor{Preset::TYPE_PRINT});
+    preset.attr("printer")  = py::cast(PresetEditor{Preset::TYPE_PRINTER});
+    preset.attr("filament") = py::cast(PresetEditor{Preset::TYPE_FILAMENT});
+
    py::class_<Preset, std::unique_ptr<Preset, py::nodelete>>(host, "Preset")
        .def_readonly("type", &Preset::type)
        .def_readonly("name", &Preset::name)
@@ -1,3 +1,20 @@
+// why: keep the Windows headers ahead of libslic3r. Model.hpp pulls in Format/STEP.hpp, and
+// OCCT's Standard_Macro.hxx defines NOUSER and NOGDI on Windows so that windows.h does not
+// collide with OCCT's identifiers. Defined that early they also hide the USER and GDI
+// declarations, and the wx MSW headers Field.hpp reaches (wx/wxprec.h -> wx/msw/private.h)
+// need WNDPROC, RGB and the ::GetWindowRect family. Including windows.h first, as
+// libslic3r_gui does through pchheader.hpp or win_platform.hpp, keeps them.
+#ifdef WIN32
+    #ifndef WIN32_LEAN_AND_MEAN
+        #define WIN32_LEAN_AND_MEAN
+    #endif
+    #ifndef NOMINMAX
+        #define NOMINMAX
+    #endif
+    #include <Windows.h>
+    #include <CommCtrl.h>
+#endif
+
 #include <catch2/catch_all.hpp>

 #include <cstddef>
@@ -6,8 +23,12 @@
 #include <libslic3r/TriangleMesh.hpp>
 #include <slic3r/GUI/DockPanel.hpp>
 #include <slic3r/GUI/AuiPaneLayout.hpp>
+#include <slic3r/GUI/OptionsGroup.hpp>
 #include <slic3r/GUI/Widgets/WebHosting.hpp>

+#include <map>
+#include <utility>
+
 #include <catch2/catch_test_macros.hpp>
 #include <catch2/catch_message.hpp>
 #include <catch2/matchers/catch_matchers_floating_point.hpp>
@@ -137,6 +158,143 @@ TEST_CASE("Plugin host API exposes host-owned bundle and preset surface to Pytho
    CHECK(printers.attr("find_preset")(printer_preset.name).attr("name").cast<std::string>() == printer_preset.name);
 }

+TEST_CASE("Plugin host API exposes the editable preset category handles and guards them before Orca app initialization",
+          "[PluginHost][Python]")
+{
+    py::object host   = import_orca_module().attr("host");
+    py::object preset = host.attr("preset");
+
+    REQUIRE(has_attr(preset, "PresetEditor"));
+    REQUIRE(has_attr(preset, "process"));
+    REQUIRE(has_attr(preset, "printer"));
+    REQUIRE(has_attr(preset, "filament"));
+
+    py::object process  = preset.attr("process");
+    py::object printer  = preset.attr("printer");
+    py::object filament = preset.attr("filament");
+
+    CHECK(process.attr("type").cast<Slic3r::Preset::Type>() == Slic3r::Preset::TYPE_PRINT);
+    CHECK(printer.attr("type").cast<Slic3r::Preset::Type>() == Slic3r::Preset::TYPE_PRINTER);
+    CHECK(filament.attr("type").cast<Slic3r::Preset::Type>() == Slic3r::Preset::TYPE_FILAMENT);
+    for (const py::object& editor : { process, printer, filament })
+        CHECK(has_attr(editor, "update"));
+
+    // With no wx application the call must fail cleanly, like the rest of host.preset, and must not
+    // be mistaken for a missing attribute or an argument error.
+    for (const py::object& editor : { process, printer, filament }) {
+        try {
+            editor.attr("update")("layer_height", "0.25");
+            FAIL("preset editor update unexpectedly succeeded without a wx application");
+        } catch (const py::error_already_set& error) {
+            CHECK(error.matches(PyExc_RuntimeError));
+            CHECK(std::string(error.what()).find("OrcaSlicer application is not initialized") != std::string::npos);
+        }
+    }
+}
+
+TEST_CASE("Plugin host API exposes the filament slot form of preset update and guards it", "[PluginHost][Python]")
+{
+    py::object host   = import_orca_module().attr("host");
+    py::object preset = host.attr("preset");
+
+    // The filament editor accepts update(slot_number, key, value) as well as update(key, value); with
+    // no wx application it reaches the same clean failure as the rest of host.preset. The slot
+    // validation and the switch/cancel path need a running app, so they are not exercised here.
+    try {
+        preset.attr("filament").attr("update")(1, "layer_height", "0.25");
+        FAIL("slot-addressed filament update unexpectedly succeeded without a wx application");
+    } catch (const py::error_already_set& error) {
+        CHECK(error.matches(PyExc_RuntimeError));
+        CHECK(std::string(error.what()).find("OrcaSlicer application is not initialized") != std::string::npos);
+    }
+
+    // The process and printer editors accept only update(key, value); the slot form is rejected
+    // before any application access, naming the editor that does accept it.
+    for (const char* name : { "process", "printer" }) {
+        CAPTURE(name);
+        try {
+            preset.attr(name).attr("update")(1, "layer_height", "0.25");
+            FAIL("slot-addressed update on a non-filament editor unexpectedly succeeded");
+        } catch (const py::error_already_set& error) {
+            CHECK(error.matches(PyExc_ValueError));
+            CHECK(std::string(error.what()).find("only available on") != std::string::npos);
+        }
+    }
+}
+
+TEST_CASE("Plugin host API exposes staged preset update transactions", "[PluginHost][Python]")
+{
+    py::object preset = import_orca_module().attr("host").attr("preset");
+    py::object transaction_type = preset.attr("PresetTransaction");
+    py::object result_type = preset.attr("PresetUpdateResult");
+
+    CHECK(has_attr(transaction_type, "set"));
+    CHECK(has_attr(transaction_type, "commit"));
+    CHECK(has_attr(result_type, "target_name"));
+    CHECK(has_attr(result_type, "selection_changed"));
+    CHECK(has_attr(result_type, "slot_assignment_changed"));
+    CHECK(has_attr(result_type, "shared_slots"));
+
+    for (const char* name : { "process", "printer" }) {
+        CAPTURE(name);
+        py::object editor = preset.attr(name);
+        CHECK(has_attr(editor, "begin_update"));
+        try {
+            editor.attr("begin_update")();
+            FAIL("begin_update unexpectedly succeeded without a wx application");
+        } catch (const py::error_already_set& error) {
+            CHECK(error.matches(PyExc_RuntimeError));
+            CHECK(std::string(error.what()).find("OrcaSlicer application is not initialized") != std::string::npos);
+        }
+    }
+
+    py::object filament = preset.attr("filament");
+    CHECK(has_attr(filament, "begin_update"));
+    try {
+        filament.attr("begin_update")(1);
+        FAIL("filament begin_update unexpectedly succeeded without a wx application");
+    } catch (const py::error_already_set& error) {
+        CHECK(error.matches(PyExc_RuntimeError));
+        CHECK(std::string(error.what()).find("OrcaSlicer application is not initialized") != std::string::npos);
+    }
+}
+
+TEST_CASE("A settings group resolves an option's id from its option map", "[PluginHost]")
+{
+    using Slic3r::GUI::option_id_in_map;
+    using Slic3r::GUI::t_opt_map;
+
+    // The map ConfigOptionsGroup::get_option leaves: a scalar option, and a per-extruder option
+    // whose entries carry their index.
+    t_opt_map options;
+    options.emplace("layer_height", std::make_pair(std::string("layer_height"), -1));
+    options.emplace("nozzle_diameter#0", std::make_pair(std::string("nozzle_diameter"), 0));
+    options.emplace("nozzle_diameter#1", std::make_pair(std::string("nozzle_diameter"), 1));
+
+    // A negative index resolves a scalar option and yields its own (negative) index.
+    int index = -1;
+    CHECK(option_id_in_map(options, "layer_height", index) == "layer_height");
+    CHECK(index == -1);
+
+    // A negative index on a vector option matches several entries, so it resolves to nothing.
+    index = -1;
+    CHECK(option_id_in_map(options, "nozzle_diameter", index).empty());
+
+    // An explicit index selects that entry.
+    index = 1;
+    CHECK(option_id_in_map(options, "nozzle_diameter", index) == "nozzle_diameter#1");
+    CHECK(index == 1);
+
+    // An index no entry carries, and a key the map does not own, resolve to nothing.
+    index = 7;
+    CHECK(option_id_in_map(options, "nozzle_diameter", index).empty());
+    index = -1;
+    CHECK(option_id_in_map(options, "wall_loops", index).empty());
+
+    const t_opt_map empty;
+    CHECK(option_id_in_map(empty, "layer_height", index).empty());
+}
+
 TEST_CASE("Plugin host API reports unavailable GUI objects before Orca app initialization", "[PluginHost][Python]")
 {
    py::object host = import_orca_module().attr("host");
Author	SHA1	Message	Date
Ian Chua	1b4dd2044f	Merge branch 'main' into feat/preset-plugin-apis	2026-10-17 15:18:45 +08:00
peachismomo	b7f9888516	fix: update demo plugins	2026-10-17 15:09:21 +08:00
peachismomo	0b478a1d0b	fix: remove async behavior and clang-tidy	2026-10-17 15:09:06 +08:00
peachismomo	d80af50f23	feat: preset APIs	2026-10-17 01:44:15 +08:00
peachismomo	3bfe40e17a	Merge branch 'main' into feat/preset-plugin-apis	2026-10-16 21:59:48 +08:00
Ian Chua	62f05dad2b	doc: HLSD for preset plugin APIs	2026-10-16 21:54:34 +08:00
peachismomo	4d3c61c02a	fix: tests	2026-10-16 19:12:30 +08:00
peachismomo	dc9203126d	fix: tests	2026-10-15 21:00:39 +08:00
Ian Chua	8c2a1198d6	Merge branch 'main' into feat/preset-plugin-apis	2026-10-15 20:46:38 +08:00
Ian Chua	193cfc6dbf	feat: introduce plugin APIs for mutable presets	2026-10-15 20:32:49 +08:00