diff --git a/tests/console_test_phase5.py b/tests/console_test_phase5.py
new file mode 100644
index 0000000..0255fa7
--- /dev/null
+++ b/tests/console_test_phase5.py
@@ -0,0 +1,355 @@
+"""
+Phase 5 in-client console tests.
+
+Paste into the FreeCAD Python console (or run via: exec(open(...).read())).
+Tests the full Assembly -> KindredSolver pipeline without the unittest harness.
+
+Expected output: all lines print PASS. Any FAIL indicates a regression.
+"""
+
+import FreeCAD as App
+import JointObject
+import kcsolve
+
+_pref = App.ParamGet("User parameter:BaseApp/Preferences/Mod/Assembly")
+_orig_solver = _pref.GetString("Solver", "")
+
+_results = []
+
+
+def _report(name, passed, detail=""):
+    status = "PASS" if passed else "FAIL"
+    msg = f"  [{status}] {name}"
+    if detail:
+        msg += f" — {detail}"
+    print(msg)
+    _results.append((name, passed))
+
+
+def _new_doc(name="Phase5Test"):
+    if App.ActiveDocument and App.ActiveDocument.Name == name:
+        App.closeDocument(name)
+    App.newDocument(name)
+    App.setActiveDocument(name)
+    return App.ActiveDocument
+
+
+def _cleanup(doc):
+    App.closeDocument(doc.Name)
+
+
+def _make_assembly(doc):
+    asm = doc.addObject("Assembly::AssemblyObject", "Assembly")
+    asm.resetSolver()
+    jg = asm.newObject("Assembly::JointGroup", "Joints")
+    return asm, jg
+
+
+def _make_box(asm, x=0, y=0, z=0, size=10):
+    box = asm.newObject("Part::Box", "Box")
+    box.Length = size
+    box.Width = size
+    box.Height = size
+    box.Placement = App.Placement(App.Vector(x, y, z), App.Rotation())
+    return box
+
+
+def _ground(jg, obj):
+    gnd = jg.newObject("App::FeaturePython", "GroundedJoint")
+    JointObject.GroundedJoint(gnd, obj)
+    return gnd
+
+
+def _make_joint(jg, joint_type, ref1, ref2):
+    joint = jg.newObject("App::FeaturePython", "Joint")
+    JointObject.Joint(joint, joint_type)
+    refs = [[ref1[0], ref1[1]], [ref2[0], ref2[1]]]
+    joint.Proxy.setJointConnectors(joint, refs)
+    return joint
+
+
+# ── Test 1: Registry ────────────────────────────────────────────────
+
+
+def test_solver_registry():
+    """Verify kindred solver is registered and available."""
+    names = kcsolve.available()
+    _report(
+        "registry: kindred in available()", "kindred" in names, f"available={names}"
+    )
+
+    solver = kcsolve.load("kindred")
+    _report("registry: load('kindred') succeeds", solver is not None)
+    _report(
+        "registry: solver name",
+        solver.name() == "Kindred (Newton-Raphson)",
+        f"got '{solver.name()}'",
+    )
+
+    joints = solver.supported_joints()
+    _report(
+        "registry: supported_joints non-empty",
+        len(joints) > 0,
+        f"{len(joints)} joint types",
+    )
+
+
+# ── Test 2: Preference switching ────────────────────────────────────
+
+
+def test_preference_switching():
+    """Verify solver preference controls which backend is used."""
+    doc = _new_doc("PrefTest")
+    try:
+        # Set to kindred
+        _pref.SetString("Solver", "kindred")
+        asm, jg = _make_assembly(doc)
+
+        box1 = _make_box(asm, 0, 0, 0)
+        box2 = _make_box(asm, 50, 0, 0)
+        _ground(box1)
+        _make_joint(jg, 0, [box1, ["Face6", "Vertex7"]], [box2, ["Face6", "Vertex7"]])
+
+        result = asm.solve()
+        _report(
+            "pref: kindred solve succeeds", result == 0, f"solve() returned {result}"
+        )
+
+        # Switch back to ondsel
+        _pref.SetString("Solver", "ondsel")
+        asm.resetSolver()
+        result2 = asm.solve()
+        _report(
+            "pref: ondsel solve succeeds after switch",
+            result2 == 0,
+            f"solve() returned {result2}",
+        )
+    finally:
+        _cleanup(doc)
+
+
+# ── Test 3: Fixed joint ─────────────────────────────────────────────
+
+
+def test_fixed_joint():
+    """Two boxes + ground + fixed joint -> placements match."""
+    _pref.SetString("Solver", "kindred")
+    doc = _new_doc("FixedTest")
+    try:
+        asm, jg = _make_assembly(doc)
+        box1 = _make_box(asm, 10, 20, 30)
+        box2 = _make_box(asm, 40, 50, 60)
+        _ground(box2)
+        _make_joint(jg, 0, [box2, ["Face6", "Vertex7"]], [box1, ["Face6", "Vertex7"]])
+
+        same = box1.Placement.isSame(box2.Placement, 1e-6)
+        _report(
+            "fixed: box1 matches box2 placement",
+            same,
+            f"box1={box1.Placement.Base}, box2={box2.Placement.Base}",
+        )
+    finally:
+        _cleanup(doc)
+
+
+# ── Test 4: Revolute joint + DOF ─────────────────────────────────────
+
+
+def test_revolute_dof():
+    """Revolute joint -> solve succeeds, DOF = 1."""
+    _pref.SetString("Solver", "kindred")
+    doc = _new_doc("RevoluteTest")
+    try:
+        asm, jg = _make_assembly(doc)
+        box1 = _make_box(asm, 0, 0, 0)
+        box2 = _make_box(asm, 100, 0, 0)
+        _ground(box1)
+        _make_joint(jg, 1, [box1, ["Face6", "Vertex7"]], [box2, ["Face6", "Vertex7"]])
+
+        result = asm.solve()
+        _report("revolute: solve succeeds", result == 0, f"solve() returned {result}")
+
+        dof = asm.getLastDoF()
+        _report("revolute: DOF = 1", dof == 1, f"DOF = {dof}")
+    finally:
+        _cleanup(doc)
+
+
+# ── Test 5: No ground ───────────────────────────────────────────────
+
+
+def test_no_ground():
+    """No grounded parts -> returns -6."""
+    _pref.SetString("Solver", "kindred")
+    doc = _new_doc("NoGroundTest")
+    try:
+        asm, jg = _make_assembly(doc)
+        box1 = _make_box(asm, 0, 0, 0)
+        box2 = _make_box(asm, 50, 0, 0)
+
+        joint = jg.newObject("App::FeaturePython", "Joint")
+        JointObject.Joint(joint, 0)
+        refs = [[box1, ["Face6", "Vertex7"]], [box2, ["Face6", "Vertex7"]]]
+        joint.Proxy.setJointConnectors(joint, refs)
+
+        result = asm.solve()
+        _report("no-ground: returns -6", result == -6, f"solve() returned {result}")
+    finally:
+        _cleanup(doc)
+
+
+# ── Test 6: Solve stability ─────────────────────────────────────────
+
+
+def test_stability():
+    """Solving twice gives identical placements."""
+    _pref.SetString("Solver", "kindred")
+    doc = _new_doc("StabilityTest")
+    try:
+        asm, jg = _make_assembly(doc)
+        box1 = _make_box(asm, 10, 20, 30)
+        box2 = _make_box(asm, 40, 50, 60)
+        _ground(box2)
+        _make_joint(jg, 0, [box2, ["Face6", "Vertex7"]], [box1, ["Face6", "Vertex7"]])
+
+        asm.solve()
+        plc1 = App.Placement(box1.Placement)
+        asm.solve()
+        plc2 = box1.Placement
+
+        same = plc1.isSame(plc2, 1e-6)
+        _report("stability: two solves identical", same)
+    finally:
+        _cleanup(doc)
+
+
+# ── Test 7: Standalone solver API ────────────────────────────────────
+
+
+def test_standalone_api():
+    """Use kcsolve types directly without FreeCAD Assembly objects."""
+    solver = kcsolve.load("kindred")
+
+    # Two parts: one grounded, one free
+    p1 = kcsolve.Part()
+    p1.id = "base"
+    p1.placement = kcsolve.Transform.identity()
+    p1.grounded = True
+
+    p2 = kcsolve.Part()
+    p2.id = "arm"
+    p2.placement = kcsolve.Transform()
+    p2.placement.position = [100.0, 0.0, 0.0]
+    p2.placement.quaternion = [1.0, 0.0, 0.0, 0.0]
+    p2.grounded = False
+
+    # Fixed joint
+    c = kcsolve.Constraint()
+    c.id = "fix1"
+    c.part_i = "base"
+    c.marker_i = kcsolve.Transform.identity()
+    c.part_j = "arm"
+    c.marker_j = kcsolve.Transform.identity()
+    c.type = kcsolve.BaseJointKind.Fixed
+
+    ctx = kcsolve.SolveContext()
+    ctx.parts = [p1, p2]
+    ctx.constraints = [c]
+
+    result = solver.solve(ctx)
+    _report(
+        "standalone: solve status",
+        result.status == kcsolve.SolveStatus.Success,
+        f"status={result.status}",
+    )
+    _report("standalone: DOF = 0", result.dof == 0, f"dof={result.dof}")
+
+    # Check that arm moved to origin
+    for pr in result.placements:
+        if pr.id == "arm":
+            dist = sum(x**2 for x in pr.placement.position) ** 0.5
+            _report("standalone: arm at origin", dist < 1e-6, f"distance={dist:.2e}")
+            break
+
+
+# ── Test 8: Diagnose API ────────────────────────────────────────────
+
+
+def test_diagnose():
+    """Diagnose overconstrained system via standalone API."""
+    solver = kcsolve.load("kindred")
+
+    p1 = kcsolve.Part()
+    p1.id = "base"
+    p1.placement = kcsolve.Transform.identity()
+    p1.grounded = True
+
+    p2 = kcsolve.Part()
+    p2.id = "arm"
+    p2.placement = kcsolve.Transform()
+    p2.placement.position = [50.0, 0.0, 0.0]
+    p2.placement.quaternion = [1.0, 0.0, 0.0, 0.0]
+    p2.grounded = False
+
+    # Two fixed joints = overconstrained
+    c1 = kcsolve.Constraint()
+    c1.id = "fix1"
+    c1.part_i = "base"
+    c1.marker_i = kcsolve.Transform.identity()
+    c1.part_j = "arm"
+    c1.marker_j = kcsolve.Transform.identity()
+    c1.type = kcsolve.BaseJointKind.Fixed
+
+    c2 = kcsolve.Constraint()
+    c2.id = "fix2"
+    c2.part_i = "base"
+    c2.marker_i = kcsolve.Transform.identity()
+    c2.part_j = "arm"
+    c2.marker_j = kcsolve.Transform.identity()
+    c2.type = kcsolve.BaseJointKind.Fixed
+
+    ctx = kcsolve.SolveContext()
+    ctx.parts = [p1, p2]
+    ctx.constraints = [c1, c2]
+
+    diags = solver.diagnose(ctx)
+    _report(
+        "diagnose: returns diagnostics", len(diags) > 0, f"{len(diags)} diagnostic(s)"
+    )
+    if diags:
+        kinds = [d.kind for d in diags]
+        _report(
+            "diagnose: found redundant",
+            kcsolve.DiagnosticKind.Redundant in kinds,
+            f"kinds={[str(k) for k in kinds]}",
+        )
+
+
+# ── Run all ──────────────────────────────────────────────────────────
+
+
+def run_all():
+    print("\n=== Phase 5 Console Tests ===\n")
+
+    test_solver_registry()
+    test_preference_switching()
+    test_fixed_joint()
+    test_revolute_dof()
+    test_no_ground()
+    test_stability()
+    test_standalone_api()
+    test_diagnose()
+
+    # Restore original preference
+    _pref.SetString("Solver", _orig_solver)
+
+    # Summary
+    passed = sum(1 for _, p in _results if p)
+    total = len(_results)
+    print(f"\n=== {passed}/{total} passed ===\n")
+    if passed < total:
+        failed = [name for name, p in _results if not p]
+        print(f"FAILED: {', '.join(failed)}")
+
+
+run_all()