diff --git a/.github/workflows/godot-headless.yml b/.github/workflows/godot-headless.yml
index ccbece5..d523f25 100644
--- a/.github/workflows/godot-headless.yml
+++ b/.github/workflows/godot-headless.yml
@@ -67,11 +67,22 @@ jobs:
               fi
               grep -q "DROP_QUALITY_OK" "$QOUT"
               [ "$QRC" -eq 0 ]
+              EOUT=$(mktemp)
+              set +e
+              godot --headless --path /src -s res://tools/test_eartip_quality.gd 2>&1 | tee "$EOUT"
+              ERC=${PIPESTATUS[0]}
+              set -e
+              if grep -E "Parse Error|Failed to load script|EARTIP_QUALITY_FAIL" "$EOUT"; then
+                echo "::error::Godot eartip quality (fall-through) failure"
+                exit 1
+              fi
+              grep -q "EARTIP_QUALITY_OK" "$EOUT"
+              [ "$ERC" -eq 0 ]
             '
 
       - name: Summarize
         if: always()
         run: |
           echo "### Godot CI" >> "$GITHUB_STEP_SUMMARY"
-          echo "Self-hosted Docker \`ghcr.io/sharkyrawr/godot-docker:4.6\` — bake + \`test_contact\` + \`test_drop_quality\` (Julian flat/roof model)" >> "$GITHUB_STEP_SUMMARY"
+          echo "bake + contact + drop_quality (flat/roof) + **eartip penetration** (\`test_eartip_quality.gd\`)" >> "$GITHUB_STEP_SUMMARY"
           echo "Status: ${{ job.status }}" >> "$GITHUB_STEP_SUMMARY"
diff --git a/barmesh/draw.gd b/barmesh/draw.gd
index 4a6e20d..f4f8fc3 100644
--- a/barmesh/draw.gd
+++ b/barmesh/draw.gd
@@ -20,6 +20,7 @@ const Contact = preload("res://barmesh/tool_contact.gd")
 var _playing: bool = false
 var _run_id: int = 0
 var _last_bm: BarMesh
+var _last_tris: Array = []
 var _normals_mi: MeshInstance3D
 
 
@@ -28,6 +29,14 @@ static func cad_to_godot(p: Vector3) -> Vector3:
 	return Vector3(p.x, p.z, p.y)
 
 
+func get_last_barmesh() -> BarMesh:
+	return _last_bm
+
+
+func get_last_tris_cad() -> Array:
+	return _last_tris
+
+
 func _ready() -> void:
 	var mat := StandardMaterial3D.new()
 	mat.shading_mode = BaseMaterial3D.SHADING_MODE_UNSHADED
@@ -71,6 +80,7 @@ func play_over_part(p_radius: float = -1.0) -> void:
 	var ypart := BarMeshGD.Partition1.new(cad["ymin"], cad["ymax"], ny)
 	var z_above: float = cad["zmax"] + R + pad_m
 	var z_plane: float = cad["zmin"]
+	_last_tris = tris
 	var bm := BarMeshGD.new()
 	bm.start_rect_bar_mesh(xpart, ypart, z_above)
 	var more := true
diff --git a/barmesh/tool_contact.gd b/barmesh/tool_contact.gd
index 6147558..8c32cc8 100644
--- a/barmesh/tool_contact.gd
+++ b/barmesh/tool_contact.gd
@@ -280,3 +280,74 @@ static func _point_in_triangle(p: Vector3, a: Vector3, b: Vector3, c: Vector3) -
 	var u := 1.0 - v - w
 	var eps := -1e-6
 	return u >= eps and v >= eps and w >= eps
+
+
+static func highest_surface_z_at_xy(x: float, y: float, tris_cad: Array) -> float:
+	## Highest mesh z along vertical line (x,y,*) — for fall-through vs top skin.
+	var z_best: float = -1e30
+	var found := false
+	for tri in tris_cad:
+		var a: Vector3 = tri[0]
+		var b: Vector3 = tri[1]
+		var c: Vector3 = tri[2]
+		var n := (b - a).cross(c - a)
+		if absf(n.z) < 1e-12:
+			continue
+		# Plane: n·(p-a)=0 → z = a.z + (-n.x*(x-a.x)-n.y*(y-a.y))/n.z
+		var z: float = a.z - (n.x * (x - a.x) + n.y * (y - a.y)) / n.z
+		var p := Vector3(x, y, z)
+		if not _point_in_triangle(p, a, b, c):
+			continue
+		if z > z_best:
+			z_best = z
+			found = true
+	if not found:
+		return NAN
+	return z_best
+
+
+static func min_distance_point_to_tris(p: Vector3, tris_cad: Array) -> float:
+	## Closest distance from point to any triangle (for sphere penetration checks).
+	var best: float = 1e30
+	for tri in tris_cad:
+		var d: float = _point_triangle_distance(p, tri[0], tri[1], tri[2])
+		if d < best:
+			best = d
+	return best
+
+
+static func _point_triangle_distance(p: Vector3, a: Vector3, b: Vector3, c: Vector3) -> float:
+	var ab := b - a
+	var ac := c - a
+	var ap := p - a
+	var d1 := ab.dot(ap)
+	var d2 := ac.dot(ap)
+	if d1 <= 0.0 and d2 <= 0.0:
+		return ap.length()
+	var bp := p - b
+	var d3 := ab.dot(bp)
+	var d4 := ac.dot(bp)
+	if d3 >= 0.0 and d4 <= d3:
+		return bp.length()
+	var vc := d1 * d4 - d3 * d2
+	if vc <= 0.0 and d1 >= 0.0 and d3 <= 0.0:
+		var v: float = d1 / (d1 - d3)
+		return (a + ab * v - p).length()
+	var cp := p - c
+	var d5 := ab.dot(cp)
+	var d6 := ac.dot(cp)
+	if d6 >= 0.0 and d5 <= d6:
+		return cp.length()
+	var vb := d5 * d2 - d1 * d6
+	if vb <= 0.0 and d2 >= 0.0 and d6 <= 0.0:
+		var w: float = d2 / (d2 - d6)
+		return (a + ac * w - p).length()
+	var va := d3 * d6 - d5 * d4
+	if va <= 0.0 and (d4 - d3) >= 0.0 and (d5 - d6) >= 0.0:
+		var w2: float = (d4 - d3) / ((d4 - d3) + (d5 - d6))
+		return (b + (c - b) * w2 - p).length()
+	var n := ab.cross(ac)
+	var nlen2 := n.length_squared()
+	if nlen2 < 1e-24:
+		return ap.length()
+	return absf(n.dot(ap)) / sqrt(nlen2)
diff --git a/tools/test_eartip_quality.gd b/tools/test_eartip_quality.gd
new file mode 100644
index 0000000..3ac19e1
--- /dev/null
+++ b/tools/test_eartip_quality.gd
@@ -0,0 +1,142 @@
+extends SceneTree
+## CI: bake BarMesh on the real eartip and fail on fall-through.
+## Checks: |CL−contact|≈R; sphere not penetrating drop tris; CL not below top skin at XY.
+## Headless: godot --headless --path . -s res://tools/test_eartip_quality.gd
+
+const Contact := preload("res://barmesh/tool_contact.gd")
+
+
+func _init() -> void:
+	call_deferred("_run")
+
+
+func _fail(msg: String) -> void:
+	push_error("EARTIP_QUALITY_FAIL " + msg)
+	quit(1)
+
+
+func _run() -> void:
+	var packed: PackedScene = load("res://scenes/main.tscn")
+	if packed == null:
+		_fail("load main")
+		return
+	var root: Node = packed.instantiate()
+	root.name = "Main"
+	get_root().add_child(root)
+	for i in 8:
+		await process_frame
+
+	var R_mm := 1.5
+	var R := R_mm * 0.001
+	var stats: Dictionary = await root.bake_strategy("barmesh", R_mm, 1.0, 0.01, 15.0)
+	if stats.is_empty():
+		_fail("bake empty")
+		return
+
+	var preview := root.get_node_or_null("BarMeshPreview")
+	if preview == null or not preview.has_method("get_last_barmesh"):
+		_fail("no preview accessors")
+		return
+	var bm = preview.get_last_barmesh()
+	var tris: Array = preview.get_last_tris_cad()
+	if bm == null or bm.nodes.is_empty():
+		_fail("empty barmesh")
+		return
+	if tris.is_empty():
+		_fail("empty tris")
+		return
+
+	# Part-only tris (exclude synthetic base plane at zmin) for top-skin checks.
+	var zmin := 1e30
+	for tri in tris:
+		for v in tri:
+			zmin = minf(zmin, v.z)
+	var part_tris: Array = []
+	for tri in tris:
+		var on_base := true
+		for v in tri:
+			if absf(v.z - zmin) > 1e-6:
+				on_base = false
+				break
+		if not on_base:
+			part_tris.append(tri)
+
+	var tol := 2e-4
+	var checked := 0
+	var below_skin := 0
+	var low_flat := 0
+	var penetrations := 0
+	var worst_below := 0.0
+	var worst_flat := 0.0
+	var worst_at := Vector3.ZERO
+	for node in bm.nodes:
+		var nd = node
+		if nd.contact_kind == 0:
+			continue
+		var cl: Vector3 = nd.p
+		var d_contact: float = cl.distance_to(nd.contact_point)
+		if absf(d_contact - R) > tol:
+			_fail("|CL-contact|!=R d=%s R=%s at %s" % [d_contact, R, cl])
+			return
+		var d_mesh: float = Contact.min_distance_point_to_tris(cl, tris)
+		if d_mesh < R - tol:
+			penetrations += 1
+		var z_skin: float = Contact.highest_surface_z_at_xy(cl.x, cl.y, part_tris)
+		if is_finite(z_skin) and cl.z < z_skin - tol:
+			below_skin += 1
+			var depth: float = z_skin - cl.z
+			if depth > worst_below:
+				worst_below = depth
+				worst_at = cl
+			if below_skin <= 8:
+				push_warning(
+					"EARTIP_BELOW_SKIN cl.z=%s skin=%s depth_mm=%s at (%s,%s)"
+					% [cl.z, z_skin, depth * 1000.0, cl.x, cl.y]
+				)
+		# Near-horizontal skin: ball CL must be ~ skin + R (Julian fall-through class).
+		if is_finite(z_skin) and nd.contact_normal.z > 0.92:
+			var expect_z: float = z_skin + R * nd.contact_normal.z
+			if cl.z < expect_z - tol:
+				low_flat += 1
+				var gap: float = expect_z - cl.z
+				if gap > worst_flat:
+					worst_flat = gap
+					worst_at = cl
+				if low_flat <= 8:
+					push_warning(
+						"EARTIP_LOW_FLAT cl.z=%s expect=%s gap_mm=%s at (%s,%s)"
+						% [cl.z, expect_z, gap * 1000.0, cl.x, cl.y]
+					)
+		checked += 1
+
+	if checked < 10:
+		_fail("too few contact nodes " + str(checked))
+		return
+
+	if penetrations > 0:
+		_fail("sphere penetration at %s of %s nodes" % [penetrations, checked])
+		return
+
+	if below_skin > 0:
+		_fail(
+			"CL below top skin at %s of %s nodes; worst depth_mm=%s at %s"
+			% [below_skin, checked, worst_below * 1000.0, worst_at]
+		)
+		return
+
+	if low_flat > 0:
+		_fail(
+			"CL too low on flat skin at %s of %s nodes; worst gap_mm=%s at %s"
+			% [low_flat, checked, worst_flat * 1000.0, worst_at]
+		)
+		return
+
+	print(
+		"EARTIP_QUALITY_OK nodes=",
+		checked,
+		" part_tris=",
+		part_tris.size(),
+		" R_mm=",
+		R_mm
+	)
+	quit(0)