fix(review-followup-fea): clarify Stop with queued input

3 files changed, 46 insertions, 0 deletions

diff --git a/src/features/surface-host/index.ts b/src/features/surface-host/index.ts
index 1e21e3d..f6a3041 100644
--- a/src/features/surface-host/index.ts
+++ b/src/features/surface-host/index.ts
@@ -1,3 +1,4 @@
+export { MESSAGE_QUEUE_RENDERER_ID, messageQueueCount } from "./logic/message-queue";
 export { buildInvoke, planSurface } from "./logic/plan";
 export type { FieldView, SurfaceRenderPlan } from "./logic/types";
 export { default as SurfaceView } from "./ui/SurfaceView.svelte";
diff --git a/src/features/surface-host/logic/message-queue.test.ts b/src/features/surface-host/logic/message-queue.test.ts
index ae91c8f..93256b4 100644
--- a/src/features/surface-host/logic/message-queue.test.ts
+++ b/src/features/surface-host/logic/message-queue.test.ts
@@ -1,6 +1,8 @@
+import type { SurfaceSpec } from "@dispatch/ui-contract";
 import type { QueuedMessage } from "@dispatch/wire";
 import { describe, expect, it } from "vitest";
 import {
+  messageQueueCount,
   parseMessageQueuePayload,
   reconcileCancelledIds,
   selectVisibleMessages,
@@ -103,3 +105,36 @@ describe("reconcileCancelledIds", () => {
     expect([...result]).toEqual(["m2"]);
   });
 });
+
+describe("messageQueueCount", () => {
+  const spec = (payload: unknown): SurfaceSpec => ({
+    id: "message-queue",
+    region: "inline",
+    title: "Message queue",
+    fields: [{ kind: "custom", rendererId: "message-queue", payload }],
+  });
+
+  it("counts messages, including image-only input", () => {
+    expect(messageQueueCount(spec({ messages: [msg("m1", ""), msg("m2", "next")] }))).toBe(2);
+  });
+
+  it("distinguishes an empty queue from an unavailable snapshot", () => {
+    expect(messageQueueCount(spec({ messages: [] }))).toBe(0);
+    expect(messageQueueCount(null)).toBeUndefined();
+  });
+
+  it("returns unknown for missing fields or a different renderer", () => {
+    expect(messageQueueCount({ ...spec(null), fields: [] })).toBeUndefined();
+    expect(
+      messageQueueCount({
+        ...spec(null),
+        fields: [{ kind: "custom", rendererId: "other", payload: { messages: [msg("m1", "x")] } }],
+      }),
+    ).toBeUndefined();
+  });
+
+  it("returns unknown for malformed payloads", () => {
+    expect(messageQueueCount(spec({ messages: "nope" }))).toBeUndefined();
+    expect(messageQueueCount(spec({ messages: [{ id: "m1" }] }))).toBeUndefined();
+  });
+});
diff --git a/src/features/surface-host/logic/message-queue.ts b/src/features/surface-host/logic/message-queue.ts
index 7a3653e..a49d4d0 100644
--- a/src/features/surface-host/logic/message-queue.ts
+++ b/src/features/surface-host/logic/message-queue.ts
@@ -1,3 +1,4 @@
+import type { SurfaceSpec } from "@dispatch/ui-contract";
 import type { QueuedMessage } from "@dispatch/wire";
 
 /**
@@ -41,6 +42,15 @@ export function parseMessageQueuePayload(payload: unknown): MessageQueueData | n
   return { messages };
 }
 
+/** Queue size from a validated snapshot; absent/malformed data stays unknown. */
+export function messageQueueCount(spec: SurfaceSpec | null): number | undefined {
+  const field = spec?.fields.find(
+    (field) => field.kind === "custom" && field.rendererId === MESSAGE_QUEUE_RENDERER_ID,
+  );
+  if (field?.kind !== "custom") return undefined;
+  return parseMessageQueuePayload(field.payload)?.messages.length;
+}
+
 /** The `rendererId` the message-queue extension's `custom` surface field uses. */
 export const MESSAGE_QUEUE_RENDERER_ID = "message-queue";