diff --git a/canvas/src/store/__tests__/canvas.test.ts b/canvas/src/store/__tests__/canvas.test.ts
index e3410b147..1667c9ede 100644
--- a/canvas/src/store/__tests__/canvas.test.ts
+++ b/canvas/src/store/__tests__/canvas.test.ts
@@ -1224,3 +1224,117 @@ describe("moveNode", () => {
     });
   });
 });
+
+describe("arrangeChildren", () => {
+  it("is a no-op when the parent has no children", () => {
+    useCanvasStore.getState().hydrate([
+      makeWS({ id: "parent", name: "Parent", x: 100, y: 200 }),
+    ]);
+    expect(() => useCanvasStore.getState().arrangeChildren("parent")).not.toThrow();
+    // No fetch calls should be made
+    expect(global.fetch).not.toHaveBeenCalled();
+  });
+
+  it("sorts children by name and assigns default slot positions", () => {
+    // Children are: Bob, Alice — after localeSort: Alice(0), Bob(1)
+    // defaultChildSlot(0) = {x: 16, y: 130} (PARENT_SIDE_PADDING, PARENT_HEADER_PADDING)
+    // defaultChildSlot(1) = {x: 270, y: 130} (16 + 240 + 14, 130)
+    useCanvasStore.getState().hydrate([
+      makeWS({ id: "parent", name: "Parent", x: 100, y: 200 }),
+      makeWS({ id: "ws-bob", name: "Bob", x: 0, y: 0, parent_id: "parent" }),
+      makeWS({ id: "ws-alice", name: "Alice", x: 0, y: 0, parent_id: "parent" }),
+    ]);
+
+    useCanvasStore.getState().arrangeChildren("parent");
+
+    const nodes = useCanvasStore.getState().nodes;
+    const alice = nodes.find((n) => n.id === "ws-alice")!;
+    const bob = nodes.find((n) => n.id === "ws-bob")!;
+
+    // Alice is first alphabetically → index 0 → {x: 16, y: 130}
+    expect(alice.position).toEqual({ x: 16, y: 130 });
+    // Bob is second alphabetically → index 1 → {x: 270, y: 130}
+    expect(bob.position).toEqual({ x: 270, y: 130 });
+  });
+
+  it("PATCHes each child with absolute canvas coordinates (parent position + slot)", async () => {
+    // Parent at (100, 200). Alice slot = {x: 16, y: 130}.
+    // absX = 16 + 100 = 116, absY = 130 + 200 = 330.
+    const mock = global.fetch as ReturnType<typeof vi.fn>;
+    useCanvasStore.getState().hydrate([
+      makeWS({ id: "parent", name: "Parent", x: 100, y: 200 }),
+      makeWS({ id: "ws-alice", name: "Alice", x: 0, y: 0, parent_id: "parent" }),
+    ]);
+
+    useCanvasStore.getState().arrangeChildren("parent");
+
+    await vi.waitFor(() => {
+      expect(mock).toHaveBeenCalledWith(
+        expect.stringContaining("/workspaces/ws-alice"),
+        expect.objectContaining({
+          method: "PATCH",
+          body: JSON.stringify({ x: 116, y: 330 }),
+        }),
+      );
+    });
+  });
+});
+
+describe("setCollapsed", () => {
+  it("collapsing a parent hides its direct child", () => {
+    // parentMinSizeFromChildren([{width:240, height:130}]) = {width: 560, height: 302}
+    useCanvasStore.getState().hydrate([
+      makeWS({ id: "parent", name: "Parent" }),
+      makeWS({ id: "child", name: "Child", parent_id: "parent" }),
+    ]);
+    // Manually set parent size so it has an expanded size
+    useCanvasStore.setState({
+      nodes: useCanvasStore.getState().nodes.map((n) =>
+        n.id === "parent" ? { ...n, width: 560, height: 302 } : n,
+      ),
+    });
+
+    useCanvasStore.getState().setCollapsed("parent", true);
+
+    const parent = useCanvasStore.getState().nodes.find((n) => n.id === "parent")!;
+    const child = useCanvasStore.getState().nodes.find((n) => n.id === "child")!;
+
+    expect(parent.data.collapsed).toBe(true);
+    expect(parent.width).toBe(240);  // CHILD_DEFAULT_WIDTH
+    expect(parent.height).toBe(130); // CHILD_DEFAULT_HEIGHT
+    expect(child.hidden).toBe(true); // child is hidden because parent is collapsed
+  });
+
+  it("expanding a parent reveals its direct child", () => {
+    useCanvasStore.getState().hydrate([
+      makeWS({ id: "parent", name: "Parent" }),
+      makeWS({ id: "child", name: "Child", parent_id: "parent" }),
+    ]);
+    useCanvasStore.setState({
+      nodes: useCanvasStore.getState().nodes.map((n) =>
+        n.id === "parent"
+          ? { ...n, width: 240, height: 130, data: { ...n.data, collapsed: true } }
+          : n,
+      ),
+    });
+
+    useCanvasStore.getState().setCollapsed("parent", false);
+
+    const parent = useCanvasStore.getState().nodes.find((n) => n.id === "parent")!;
+    const child = useCanvasStore.getState().nodes.find((n) => n.id === "child")!;
+
+    expect(parent.data.collapsed).toBe(false);
+    expect(child.hidden).toBe(false); // child is visible when parent is expanded
+  });
+
+  it("is a no-op for a non-existent parentId", () => {
+    useCanvasStore.getState().hydrate([
+      makeWS({ id: "parent", name: "Parent" }),
+      makeWS({ id: "child", name: "Child", parent_id: "parent" }),
+    ]);
+    // Should not throw even when parentId doesn't exist
+    expect(() => useCanvasStore.getState().setCollapsed("nonexistent", true)).not.toThrow();
+    // Nodes should be unchanged
+    expect(useCanvasStore.getState().nodes).toHaveLength(2);
+  });
+});
diff --git a/workspace-server/internal/handlers/a2a_queue_status_test.go b/workspace-server/internal/handlers/a2a_queue_status_test.go
index 1bae7fbdc..cb4044468 100644
--- a/workspace-server/internal/handlers/a2a_queue_status_test.go
+++ b/workspace-server/internal/handlers/a2a_queue_status_test.go
@@ -1,7 +1,16 @@
 package handlers
 
 import (
+	"context"
+	"database/sql"
+	"encoding/json"
+	"errors"
+	"net/http"
+	"net/http/httptest"
 	"testing"
+
+	"github.com/DATA-DOG/go-sqlmock"
+	"github.com/gin-gonic/gin"
 )
 
 // TestExtractExpiresInSeconds covers the JSON parser used at enqueue time
@@ -58,3 +67,361 @@ func TestExtractExpiresInSeconds(t *testing.T) {
 		})
 	}
 }
+
+// ─── QueueDepth ─────────────────────────────────────────────────────────────
+
+// TestQueueDepth_Success verifies QueueDepth returns the COUNT of queued items
+// for a workspace.
+func TestQueueDepth_Success(t *testing.T) {
+	mock := setupTestDB(t)
+
+	mock.ExpectQuery(`SELECT COUNT\(\*\) FROM a2a_queue WHERE workspace_id = \$1 AND status = 'queued'`).
+		WithArgs("ws-queue-depth-1").
+		WillReturnRows(sqlmock.NewRows([]string{"count"}).AddRow(7))
+
+	got := QueueDepth(context.Background(), "ws-queue-depth-1")
+	if got != 7 {
+		t.Errorf("QueueDepth() = %d; want 7", got)
+	}
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Errorf("unmet: %v", err)
+	}
+}
+
+// TestQueueDepth_EmptyQueue returns 0 when no queued items exist.
+func TestQueueDepth_EmptyQueue(t *testing.T) {
+	mock := setupTestDB(t)
+
+	mock.ExpectQuery(`SELECT COUNT\(\*\) FROM a2a_queue WHERE workspace_id = \$1 AND status = 'queued'`).
+		WithArgs("ws-empty").
+		WillReturnRows(sqlmock.NewRows([]string{"count"}).AddRow(0))
+
+	got := QueueDepth(context.Background(), "ws-empty")
+	if got != 0 {
+		t.Errorf("QueueDepth() = %d; want 0", got)
+	}
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Errorf("unmet: %v", err)
+	}
+}
+
+// TestQueueDepth_QueryError returns 0 on DB error (non-fatal; caller only uses
+// the count for display purposes).
+func TestQueueDepth_QueryError_ReturnsZero(t *testing.T) {
+	mock := setupTestDB(t)
+
+	mock.ExpectQuery(`SELECT COUNT\(\*\) FROM a2a_queue WHERE workspace_id = \$1 AND status = 'queued'`).
+		WithArgs("ws-err").
+		WillReturnError(errors.New("connection refused"))
+
+	// QueueDepth swallows the error and returns 0.
+	got := QueueDepth(context.Background(), "ws-err")
+	if got != 0 {
+		t.Errorf("QueueDepth() on error = %d; want 0", got)
+	}
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Errorf("unmet: %v", err)
+	}
+}
+
+// ─── QueueStatusByID ────────────────────────────────────────────────────────
+
+// TestQueueStatusByID_Success verifies QueueStatusByID returns a fully-populated
+// QueueStatus from the LEFT JOIN of a2a_queue and activity_logs.
+func TestQueueStatusByID_Success(t *testing.T) {
+	mock := setupTestDB(t)
+
+	// The LEFT JOIN query returns all queue columns + NULL for activity_logs
+	// when no delegation row exists.
+	mock.ExpectQuery(`SELECT\s+q\.id,\s+q\.workspace_id,\s+q\.status,\s+q\.priority,\s+q\.attempts,\s+q\.last_error,\s+q\.enqueued_at::text,\s+q\.dispatched_at::text,\s+q\.completed_at::text,\s+q\.expires_at::text,\s+al\.response_body::text\s+FROM a2a_queue q\s+LEFT JOIN activity_logs al`).
+		WithArgs("queue-ok-1").
+		WillReturnRows(sqlmock.NewRows([]string{
+			"id", "workspace_id", "status", "priority", "attempts",
+			"last_error", "enqueued_at", "dispatched_at", "completed_at", "expires_at",
+			"response_body",
+		}).AddRow(
+			"queue-ok-1", "ws-1", "queued", 50, 1,
+			nil, "2026-05-16T10:00:00Z", nil, nil, "2026-05-16T12:00:00Z",
+			nil,
+		))
+
+	qs, err := QueueStatusByID(context.Background(), "queue-ok-1")
+	if err != nil {
+		t.Fatalf("QueueStatusByID() error = %v; want nil", err)
+	}
+	if qs.ID != "queue-ok-1" {
+		t.Errorf("ID = %q; want queue-ok-1", qs.ID)
+	}
+	if qs.WorkspaceID != "ws-1" {
+		t.Errorf("WorkspaceID = %q; want ws-1", qs.WorkspaceID)
+	}
+	if qs.Status != "queued" {
+		t.Errorf("Status = %q; want queued", qs.Status)
+	}
+	if qs.Priority != 50 {
+		t.Errorf("Priority = %d; want 50", qs.Priority)
+	}
+	if qs.Attempts != 1 {
+		t.Errorf("Attempts = %d; want 1", qs.Attempts)
+	}
+	if qs.LastError != nil {
+		t.Errorf("LastError = %v; want nil", qs.LastError)
+	}
+	if qs.EnqueuedAt != "2026-05-16T10:00:00Z" {
+		t.Errorf("EnqueuedAt = %q; want 2026-05-16T10:00:00Z", qs.EnqueuedAt)
+	}
+	if qs.DispatchedAt != nil {
+		t.Errorf("DispatchedAt = %v; want nil", qs.DispatchedAt)
+	}
+	if qs.CompletedAt != nil {
+		t.Errorf("CompletedAt = %v; want nil", qs.CompletedAt)
+	}
+	if *qs.ExpiresAt != "2026-05-16T12:00:00Z" {
+		t.Errorf("ExpiresAt = %v; want 2026-05-16T12:00:00Z", qs.ExpiresAt)
+	}
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Errorf("unmet: %v", err)
+	}
+}
+
+// TestQueueStatusByID_CompletedWithResponse verifies that a completed queue item
+// populates ResponseBody from the LEFT JOINed activity_logs row.
+func TestQueueStatusByID_CompletedWithResponse(t *testing.T) {
+	mock := setupTestDB(t)
+
+	respBody := `{"result":"done"}`
+	mock.ExpectQuery(`SELECT\s+q\.id`).
+		WithArgs("queue-done-1").
+		WillReturnRows(sqlmock.NewRows([]string{
+			"id", "workspace_id", "status", "priority", "attempts",
+			"last_error", "enqueued_at", "dispatched_at", "completed_at", "expires_at",
+			"response_body",
+		}).AddRow(
+			"queue-done-1", "ws-1", "completed", 50, 1,
+			nil, "2026-05-16T10:00:00Z", "2026-05-16T10:01:00Z", "2026-05-16T10:02:00Z", nil,
+			respBody,
+		))
+
+	qs, err := QueueStatusByID(context.Background(), "queue-done-1")
+	if err != nil {
+		t.Fatalf("QueueStatusByID() error = %v; want nil", err)
+	}
+	if qs.Status != "completed" {
+		t.Errorf("Status = %q; want completed", qs.Status)
+	}
+	if qs.ResponseBody == nil {
+		t.Fatal("ResponseBody = nil; want non-nil for completed item")
+	}
+	var resp map[string]interface{}
+	if err := json.Unmarshal(qs.ResponseBody, &resp); err != nil {
+		t.Fatalf("ResponseBody not valid JSON: %v", err)
+	}
+	if resp["result"] != "done" {
+		t.Errorf("ResponseBody result = %v; want done", resp["result"])
+	}
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Errorf("unmet: %v", err)
+	}
+}
+
+// TestQueueStatusByID_ErrNoRows returns sql.ErrNoRows when the queue ID doesn't exist.
+func TestQueueStatusByID_ErrNoRows(t *testing.T) {
+	mock := setupTestDB(t)
+
+	mock.ExpectQuery(`SELECT\s+q\.id`).
+		WithArgs("queue-missing").
+		WillReturnError(sql.ErrNoRows)
+
+	_, err := QueueStatusByID(context.Background(), "queue-missing")
+	if !errors.Is(err, sql.ErrNoRows) {
+		t.Errorf("QueueStatusByID() error = %v; want sql.ErrNoRows", err)
+	}
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Errorf("unmet: %v", err)
+	}
+}
+
+// TestQueueStatusByID_QueryError propagates DB errors as-is.
+func TestQueueStatusByID_QueryError(t *testing.T) {
+	mock := setupTestDB(t)
+
+	mock.ExpectQuery(`SELECT\s+q\.id`).
+		WithArgs("queue-err").
+		WillReturnError(errors.New("connection refused"))
+
+	_, err := QueueStatusByID(context.Background(), "queue-err")
+	if err == nil {
+		t.Fatal("QueueStatusByID() error = nil; want non-nil")
+	}
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Errorf("unmet: %v", err)
+	}
+}
+
+// ─── GetA2AQueueStatus (HTTP handler) ─────────────────────────────────────
+
+func newGetA2AQueueStatusHarness(t *testing.T) (sqlmock.Sqlmock, *httptest.ResponseRecorder, *gin.Context) {
+	mock := setupTestDB(t)
+	w := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(w)
+	return mock, w, c
+}
+
+func TestGetA2AQueueStatus_MissingQueueID_Returns400(t *testing.T) {
+	_, w, c := newGetA2AQueueStatusHarness(t)
+	c.Params = gin.Params{{Key: "id", Value: "ws-1"}, {Key: "queue_id", Value: ""}}
+	c.Request = httptest.NewRequest("GET", "/", nil)
+
+	h := newHandlerWithTestDeps(t)
+	h.GetA2AQueueStatus(c)
+
+	if w.Code != http.StatusBadRequest {
+		t.Errorf("expected 400, got %d: %s", w.Code, w.Body.String())
+	}
+}
+
+func TestGetA2AQueueStatus_NoIdentity_Returns404(t *testing.T) {
+	_, w, c := newGetA2AQueueStatusHarness(t)
+	c.Params = gin.Params{{Key: "id", Value: "ws-1"}, {Key: "queue_id", Value: "q-123"}}
+	c.Request = httptest.NewRequest("GET", "/", nil)
+
+	h := newHandlerWithTestDeps(t)
+	h.GetA2AQueueStatus(c)
+
+	// Returns 404 (not 401) per the existence-non-inference policy.
+	if w.Code != http.StatusNotFound {
+		t.Errorf("expected 404, got %d: %s", w.Code, w.Body.String())
+	}
+}
+
+func TestGetA2AQueueStatus_QueueNotFound_Returns404(t *testing.T) {
+	mock, w, c := newGetA2AQueueStatusHarness(t)
+	c.Params = gin.Params{{Key: "id", Value: "ws-1"}, {Key: "queue_id", Value: "q-404"}}
+	c.Request = httptest.NewRequest("GET", "/", nil)
+	c.Request.Header.Set("X-Workspace-ID", "ws-1")
+
+	mock.ExpectQuery(`SELECT caller_id, workspace_id FROM a2a_queue WHERE id = \$1`).
+		WithArgs("q-404").
+		WillReturnError(sql.ErrNoRows)
+
+	h := newHandlerWithTestDeps(t)
+	h.GetA2AQueueStatus(c)
+
+	if w.Code != http.StatusNotFound {
+		t.Errorf("expected 404, got %d: %s", w.Code, w.Body.String())
+	}
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Errorf("unmet: %v", err)
+	}
+}
+
+func TestGetA2AQueueStatus_UnauthorizedCaller_Returns404(t *testing.T) {
+	mock, w, c := newGetA2AQueueStatusHarness(t)
+	c.Params = gin.Params{{Key: "id", Value: "ws-1"}, {Key: "queue_id", Value: "q-unauth"}}
+	c.Request = httptest.NewRequest("GET", "/", nil)
+	c.Request.Header.Set("X-Workspace-ID", "ws-wrong")
+
+	mock.ExpectQuery(`SELECT caller_id, workspace_id FROM a2a_queue WHERE id = \$1`).
+		WithArgs("q-unauth").
+		WillReturnRows(sqlmock.NewRows([]string{"caller_id", "workspace_id"}).
+			AddRow("ws-caller-a", "ws-target-b"))
+
+	h := newHandlerWithTestDeps(t)
+	h.GetA2AQueueStatus(c)
+
+	// Returns 404 per the existence-non-inference policy.
+	if w.Code != http.StatusNotFound {
+		t.Errorf("expected 404, got %d: %s", w.Code, w.Body.String())
+	}
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Errorf("unmet: %v", err)
+	}
+}
+
+func TestGetA2AQueueStatus_AuthorizedAsTarget_Success(t *testing.T) {
+	mock, w, c := newGetA2AQueueStatusHarness(t)
+	c.Params = gin.Params{{Key: "id", Value: "ws-1"}, {Key: "queue_id", Value: "q-ok"}}
+	c.Request = httptest.NewRequest("GET", "/", nil)
+	c.Request.Header.Set("X-Workspace-ID", "ws-target")
+
+	mock.ExpectQuery(`SELECT caller_id, workspace_id FROM a2a_queue WHERE id = \$1`).
+		WithArgs("q-ok").
+		WillReturnRows(sqlmock.NewRows([]string{"caller_id", "workspace_id"}).
+			AddRow("ws-caller", "ws-target"))
+
+	mock.ExpectQuery(`SELECT\s+q\.id`).
+		WithArgs("q-ok").
+		WillReturnRows(sqlmock.NewRows([]string{
+			"id", "workspace_id", "status", "priority", "attempts",
+			"last_error", "enqueued_at", "dispatched_at", "completed_at", "expires_at",
+			"response_body",
+		}).AddRow(
+			"q-ok", "ws-target", "queued", 50, 1,
+			nil, "2026-05-16T10:00:00Z", nil, nil, nil,
+			nil,
+		))
+
+	h := newHandlerWithTestDeps(t)
+	h.GetA2AQueueStatus(c)
+
+	if w.Code != http.StatusOK {
+		t.Errorf("expected 200, got %d: %s", w.Code, w.Body.String())
+	}
+	var qs QueueStatus
+	if err := json.Unmarshal(w.Body.Bytes(), &qs); err != nil {
+		t.Fatalf("body parse: %v", err)
+	}
+	if qs.ID != "q-ok" {
+		t.Errorf("queue_id = %q; want q-ok", qs.ID)
+	}
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Errorf("unmet: %v", err)
+	}
+}
+
+func TestGetA2AQueueStatus_QueueRowLookupError_Returns500(t *testing.T) {
+	mock, w, c := newGetA2AQueueStatusHarness(t)
+	c.Params = gin.Params{{Key: "id", Value: "ws-1"}, {Key: "queue_id", Value: "q-lookup-err"}}
+	c.Request = httptest.NewRequest("GET", "/", nil)
+	c.Request.Header.Set("X-Workspace-ID", "ws-1")
+
+	mock.ExpectQuery(`SELECT caller_id, workspace_id FROM a2a_queue WHERE id = \$1`).
+		WithArgs("q-lookup-err").
+		WillReturnError(errors.New("connection refused"))
+
+	h := newHandlerWithTestDeps(t)
+	h.GetA2AQueueStatus(c)
+
+	if w.Code != http.StatusInternalServerError {
+		t.Errorf("expected 500, got %d: %s", w.Code, w.Body.String())
+	}
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Errorf("unmet: %v", err)
+	}
+}
+
+func TestGetA2AQueueStatus_StatusFetchError_Returns500(t *testing.T) {
+	mock, w, c := newGetA2AQueueStatusHarness(t)
+	c.Params = gin.Params{{Key: "id", Value: "ws-1"}, {Key: "queue_id", Value: "q-status-err"}}
+	c.Request = httptest.NewRequest("GET", "/", nil)
+	c.Request.Header.Set("X-Workspace-ID", "ws-1")
+
+	mock.ExpectQuery(`SELECT caller_id, workspace_id FROM a2a_queue WHERE id = \$1`).
+		WithArgs("q-status-err").
+		WillReturnRows(sqlmock.NewRows([]string{"caller_id", "workspace_id"}).
+			AddRow("ws-1", "ws-1"))
+
+	mock.ExpectQuery(`SELECT\s+q\.id`).
+		WithArgs("q-status-err").
+		WillReturnError(errors.New("connection refused"))
+
+	h := newHandlerWithTestDeps(t)
+	h.GetA2AQueueStatus(c)
+
+	if w.Code != http.StatusInternalServerError {
+		t.Errorf("expected 500, got %d: %s", w.Code, w.Body.String())
+	}
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Errorf("unmet: %v", err)
+	}
+}