diff --git a/.gitea/workflows/check.yml b/.gitea/workflows/check.yml
index d92c4e7..088ddd4 100644
--- a/.gitea/workflows/check.yml
+++ b/.gitea/workflows/check.yml
@@ -71,7 +71,7 @@ jobs:
           PYSLACK
       - name: Fetch pinned headless HTTP integration client
         env:
-          HEADLESS_CLIENT_REVISION: 15ee91772d01b0a5cebe9853a35da31da0c0e102
+          HEADLESS_CLIENT_REVISION: dcbbdad25de7c3b1d6bee317df6074da2c0642eb
         run: |
           set -eu
           mkdir -p .headless-client
diff --git a/internal/platform/canvas_model.go b/internal/platform/canvas_model.go
index b66152b..abd4195 100644
--- a/internal/platform/canvas_model.go
+++ b/internal/platform/canvas_model.go
@@ -266,7 +266,9 @@ func validateCanvasModel(model canvasModel) error {
 				return errCanvasModel
 			}
 			if version == 1 && canvasChoice(component, "text", "image", "script", "plain-text", "plain-image", "icon", "frame") {
-				if !canvasString(data["title"], 300) || !canvasString(data["text"], 100000) || component == "frame" && geometry["rotation"] != float64(0) {
+				// Canonical frames can inherit rotation while changing owners. The
+				// legacy snapshot writer's zero-angle restriction does not apply here.
+				if !canvasString(data["title"], 300) || !canvasString(data["text"], 100000) {
 					return errCanvasModel
 				}
 				if ai, exists := data["ai"]; exists && !validCanvasAI(ai, component) {
diff --git a/internal/platform/canvas_model_test.go b/internal/platform/canvas_model_test.go
index 1b082cb..0550d2d 100644
--- a/internal/platform/canvas_model_test.go
+++ b/internal/platform/canvas_model_test.go
@@ -34,6 +34,69 @@ func modelTestDocument() canvasModel {
 	return model
 }
 
+func TestCanonicalFramesRetainRotationAcrossOwnerChanges(t *testing.T) {
+	model := modelTestDocument()
+	frame := modelTestNode("f", modelRootID)
+	frame["componentId"] = "frame"
+	frame["geometry"].(map[string]any)["rotation"] = float64(30)
+	model.Elements["f"] = frame
+	model.Canvases[modelChildID] = modelCanvas{ID: modelChildID, Parent: &modelParent{CanvasID: modelRootID, EntryElementID: "f"}}
+	model.Versions[modelChildID] = 1
+	member := modelTestNode("nested-frame", modelChildID)
+	member["componentId"] = "frame"
+	model.Elements["nested-frame"] = member
+	if err := validateCanvasModel(model); err != nil {
+		t.Fatalf("valid canonical frame rotation rejected: %v", err)
+	}
+	geometry := member["geometry"].(map[string]any)
+	moved := map[string]any{"x": float64(100), "y": float64(80), "width": float64(520), "height": float64(400), "rotation": float64(30)}
+	after, touched, err := applyModelOperations(model, []modelOperation{{ID: modelTestID(80), Changes: []modelChange{
+		{Kind: "field", Target: modelTarget{ID: "nested-frame", Incarnation: 1}, Field: "ownerCanvasId", Before: modelJSON(modelChildID), After: modelJSON(modelRootID)},
+		{Kind: "field", Target: modelTarget{ID: "nested-frame", Incarnation: 1}, Field: "geometry", Before: modelJSON(geometry), After: modelJSON(moved)},
+	}}})
+	if err != nil || !touched[modelRootID] || !touched[modelChildID] {
+		t.Fatalf("rotated frame owner change failed: %v", err)
+	}
+	if after.Elements["nested-frame"]["ownerCanvasId"] != modelRootID || !modelEqual(after.Elements["nested-frame"]["geometry"], moved) || model.Elements["nested-frame"]["ownerCanvasId"] != modelChildID {
+		t.Fatal("owner change lost geometry or changed the source model")
+	}
+	projection, err := projectCanvasModel(after)
+	if err != nil {
+		t.Fatal(err)
+	}
+	var document map[string]any
+	if err := json.Unmarshal(projection[modelRootID], &document); err != nil {
+		t.Fatal(err)
+	}
+	rotated := 0
+	for _, raw := range document["nodes"].([]any) {
+		node := raw.(map[string]any)
+		if node["id"] != "f" && node["id"] != "nested-frame" {
+			continue
+		}
+		rotated++
+		if node["data"].(map[string]any)["rotation"] != float64(30) {
+			t.Fatal("reader projection erased canonical rotation")
+		}
+	}
+	if rotated != 2 {
+		t.Fatal("reader projection omitted a rotated frame")
+	}
+	patched, err := prepareModelAIPatch(after, modelRootID, "a", response{"text": "new text"})
+	if err != nil || patched.Elements["f"]["geometry"].(map[string]any)["rotation"] != float64(30) {
+		t.Fatalf("unrelated canonical AI patch rejected or rewound rotation: %v", err)
+	}
+	bad := cloneModel(after)
+	bad.Elements["f"]["geometry"].(map[string]any)["rotation"] = float64(360)
+	if validateCanvasModel(bad) == nil {
+		t.Fatal("out-of-range canonical rotation accepted")
+	}
+	legacy := json.RawMessage(`{"schema_version":1,"nodes":[{"id":"f","type":"frame","position":{"x":0,"y":0},"width":640,"height":400,"data":{"kind":"frame","title":"F","text":"","rotation":30}}],"edges":[],"viewport":{"x":0,"y":0,"zoom":1}}`)
+	if _, valid := normalizeCanvas(legacy); valid {
+		t.Fatal("canonical support changed the legacy snapshot write contract")
+	}
+}
+
 func TestCanonicalMigrationResolvesCanvasLocalIdentitiesAndPorts(t *testing.T) {
 	root := `{"schema_version":2,"nodes":[{"id":"a","type":"plainText","position":{"x":0,"y":0},"width":240,"height":72,"data":{"kind":"plain-text","title":"parent","text":""}},{"id":"f","type":"frame","position":{"x":100,"y":200},"width":640,"height":400,"data":{"kind":"frame","title":"F","text":"","subgraph":{"boardId":"` + modelChildID + `"},"ports":[{"id":"p","nodeId":"a","handle":"right","direction":"output"}]}}],"edges":[{"id":"e","source":"f","sourceHandle":"port:p","target":"a","targetHandle":"left"}],"viewport":{"x":0,"y":0,"zoom":1}}`
 	child := `{"schema_version":2,"nodes":[{"id":"a","type":"plainText","position":{"x":10,"y":20},"width":240,"height":72,"data":{"kind":"plain-text","title":"child","text":""}}],"edges":[],"viewport":{"x":0,"y":0,"zoom":1}}`