diff --git a/scripts/kernel-test.sh b/scripts/kernel-test.sh
index 256de380c1..4176c620fc 100755
--- a/scripts/kernel-test.sh
+++ b/scripts/kernel-test.sh
@@ -31,15 +31,11 @@ IMAGE="${IMAGE:-orcacad-deps}"
 # this fork at it makes the two silently trade build artefacts. docker-iter-build.sh had the
 # identical defect and was fixed to orcacad_buildcache; this script was missed.
 VOL="${BUILD_VOL:-orcacad_kerneltest}"
-# ONE pre-existing failure is excluded by default (see [known-broken] in
-# test_caddocument.cpp): it SIGABRTs inside the vendored solver and takes the
-# whole process down, so without this exclusion a green run is simply unreachable and the
-# suite stops after ~12 of 32 cases. It is also tagged [NotWorking], the ctest label the
-# mainline fork's CI excludes, so it no longer reddens the Unit Tests job on every commit;
-# it stays tracked as snaporca-tkz rather than as CI noise. The internal-thread case that
-# used to sit alongside it is gone from this exclusion: its geometry was correct and the
-# test's reference was wrong (snaporca-kzy), so it now runs like any other.
-TAGS="${TAGS:-[CadDocument]~[known-broken]}"
+# No exclusions. Both cases that used to be quarantined now run: the solver SIGABRT on
+# circle-line tangency is fixed (snaporca-tkz), and the internal-thread case turned out to have
+# correct geometry and a wrong reference in the test (snaporca-kzy). A green run here now means
+# the whole CAD suite passed, not "everything except the two we gave up on".
+TAGS="${TAGS:-[CadDocument]}"
 HOST=""
 
 while [[ $# -gt 0 ]]; do
diff --git a/src/libslic3r/SketchSolver.cpp b/src/libslic3r/SketchSolver.cpp
index 09666ea297..f13f02b371 100644
--- a/src/libslic3r/SketchSolver.cpp
+++ b/src/libslic3r/SketchSolver.cpp
@@ -236,9 +236,31 @@ static SketchSolveResult solve_impl(std::vector<SketchEntity>& entities,
             if (aCurve && bCurve)
                 b.C(SLVS_C_CURVE_CURVE_TANGENT, 0, 0, 0, primOf(c.ea), primOf(c.eb));
             else {
-                const Slvs_hEntity arc  = aCurve ? primOf(c.ea) : primOf(c.eb);
-                const Slvs_hEntity line = aCurve ? primOf(c.eb) : primOf(c.ea);
-                b.C(SLVS_C_ARC_LINE_TANGENT, 0, 0, 0, arc, line);
+                const int ci = aCurve ? c.ea : c.eb;   // the curve
+                const int li = aCurve ? c.eb : c.ea;   // the line
+                if (valid(ci) && entities[ci].type == SketchEntity::Type::Circle) {
+                    // A FULL circle cannot use SLVS_C_ARC_LINE_TANGENT. That constraint reads
+                    // arc->point[1] / point[2] — the arc's endpoints (see constrainteq.cpp,
+                    // Type::ARC_LINE_TANGENT) — and a circle entity only has point[0], its
+                    // centre. The zero handles send FindById into "Cannot find handle", which
+                    // ABORTS the process rather than failing the solve, taking every later test
+                    // with it. It is also the wrong equation for a circle: it only makes the
+                    // line perpendicular to the radius AT AN ENDPOINT that does not exist.
+                    //
+                    // For a circle, tangency is exactly "the centre sits one radius away from
+                    // the line", which slvs expresses directly.
+                    //
+                    // ponytail: the radius is captured here rather than tied as a variable —
+                    // the C API takes a constant distance and offers no way to reference the
+                    // circle's radius parameter. Exact whenever the radius is fixed or simply
+                    // not being changed by another constraint in the same solve; if some other
+                    // constraint drives the radius, re-solving restores tangency. Tying them
+                    // would need an auxiliary point constrained onto both circle and line.
+                    b.C(SLVS_C_PT_LINE_DISTANCE, entities[ci].radius,
+                        ptOf(ci, Role::Center), 0, primOf(li), 0);
+                } else {
+                    b.C(SLVS_C_ARC_LINE_TANGENT, 0, 0, 0, primOf(ci), primOf(li));
+                }
             }
             break;
         }
diff --git a/tests/libslic3r/test_caddocument.cpp b/tests/libslic3r/test_caddocument.cpp
index d2bbf2e144..21ee86e268 100644
--- a/tests/libslic3r/test_caddocument.cpp
+++ b/tests/libslic3r/test_caddocument.cpp
@@ -608,18 +608,12 @@ TEST_CASE("entity constraints: point-on-line positions a centre onto an axis", "
     }
 }
 
-// [known-broken]: the "tangent line to circle" SECTION below aborts inside the vendored
-// solver (slvs/dsc.h FindById, "Cannot find handle"). SIGABRT is fatal to the whole Catch2
-// process, so this one case takes the entire suite down with it and no later test runs.
-// [known-broken] lets the delegated dev loop (scripts/kernel-test.sh) exclude it and still
-// reach a green baseline. [NotWorking] is the ctest label the mainline-based fork's CI already
-// excludes (run_unit_tests.sh passes -LE NotWorking, and catch_discover_tests registers Catch2
-// tags as ctest labels via ADD_TAGS_AS_LABELS) — so its Unit Tests job stops being red on every
-// single commit, which was training everyone to ignore it and would have hidden the next real
-// regression. The tag is inert on the Snapmaker fork, which has neither that runner nor
-// catch_discover_tests; the two files are kept identical because they are ported wholesale
-// between the forks. The bug stays visible in the tracker instead — see snaporca-tkz.
-TEST_CASE("entity constraints: tangent/midpoint/symmetric/angle", "[CadDocument][known-broken][NotWorking]")
+// The "tangent line to circle" SECTION used to abort the whole Catch2 process inside the
+// vendored solver (slvs/dsc.h FindById, "Cannot find handle"), taking every later test with
+// it, and was quarantined for it. Fixed in SketchSolver: a full circle can no longer be handed
+// to SLVS_C_ARC_LINE_TANGENT, which dereferences arc endpoints a circle does not have. See
+// snaporca-tkz.
+TEST_CASE("entity constraints: tangent/midpoint/symmetric/angle", "[CadDocument][sketch]")
 {
     using R = SketchPointRole;
     using T = SketchConstraintType;