fix(review-followup-fed): reconcile compaction-queued send acknowledgements

3 files changed, 287 insertions, 3 deletions

diff --git a/src/features/chat/queued.test.ts b/src/features/chat/queued.test.ts
new file mode 100644
index 0000000..3b579c6
--- /dev/null
+++ b/src/features/chat/queued.test.ts
@@ -0,0 +1,207 @@
+import type { ChatQueuedMessage } from "@dispatch/transport-contract";
+import type { AgentEvent } from "@dispatch/wire";
+import { describe, expect, it, vi } from "vitest";
+import { createChatStore } from "./store.svelte";
+import {
+  createFakeCache,
+  createFakeHistorySync,
+  createFakeMetricsSync,
+  createFakeTransport,
+} from "./test-helpers";
+
+const images = [
+  { url: "data:image/png;base64,AAAA", mimeType: "image/png" },
+  { url: "data:image/png;base64,BBBB" },
+];
+
+function fixture(batched = false) {
+  const transport = createFakeTransport();
+  const history = createFakeHistorySync();
+  let nextId = 0;
+  const scheduled: (() => void)[] = [];
+  const store = createChatStore({
+    conversationId: "c1",
+    createRequestId: () => `r${++nextId}`,
+    transport: transport.impl,
+    historySync: history.impl,
+    metricsSync: createFakeMetricsSync().impl,
+    cache: createFakeCache().impl,
+    ...(batched ? { scheduleFlush: (flush: () => void) => scheduled.push(flush) } : {}),
+  });
+  function ack(requestId: string | undefined = "r1", conversationId = "c1") {
+    const msg: ChatQueuedMessage = {
+      type: "chat.queued",
+      conversationId,
+      reason: "compaction",
+      messageId: "q1",
+      ...(requestId !== undefined ? { requestId } : {}),
+    };
+    store.handleDelta(msg);
+  }
+  function event(event: AgentEvent) {
+    store.handleDelta({ type: "chat.delta", event });
+  }
+  function start(text?: string, turnId = "t1") {
+    event({ type: "turn-start", conversationId: "c1", turnId });
+    if (text !== undefined) event({ type: "user-message", conversationId: "c1", turnId, text });
+  }
+  return { store, transport, history, scheduled, ack, event, start };
+}
+
+describe("compaction-deferred chat.send", () => {
+  it.each([
+    "hello",
+    "",
+  ])("removes just the accepted local text/images for %j without error, retry or queue sends", (text) => {
+    const f = fixture();
+    f.store.send(text, images);
+    expect(f.store.chunks).toHaveLength(text ? 3 : 2);
+    f.ack();
+    f.ack();
+    expect(f.store.chunks).toEqual([]);
+    expect(f.store.generating).toBe(false);
+    expect(f.store.error).toBeNull();
+    expect(f.transport.sent).toHaveLength(1);
+    expect(f.transport.sent[0]).toMatchObject({ requestId: "r1", images, message: text });
+    expect(f.transport.sentQueue).toEqual([]);
+    f.store.dispose();
+  });
+
+  it("uses distinct request identities for identical sends and preserves unrelated content", () => {
+    const f = fixture();
+    f.start("another client's prompt");
+    f.event({ type: "text-delta", conversationId: "c1", turnId: "t1", delta: "working" });
+    f.store.send("identical", images);
+    f.store.send("identical", images);
+    expect(f.transport.sent.map((m) => m.requestId)).toEqual(["r1", "r2"]);
+    f.ack("r1");
+    f.ack("r1");
+    expect(f.store.chunks.map((c) => c.chunk)).toEqual([
+      { type: "text", text: "another client's prompt" },
+      { type: "text", text: "working" },
+      { type: "text", text: "identical" },
+      ...images.map((i) => ({ type: "image", ...i })),
+    ]);
+    f.ack("r2");
+    expect(f.store.chunks.map((c) => c.chunk)).toEqual([
+      { type: "text", text: "another client's prompt" },
+      { type: "text", text: "working" },
+    ]);
+    expect(f.store.generating).toBe(true);
+    f.store.dispose();
+  });
+
+  it.each([
+    "missing",
+    "unknown",
+    "wrong-conversation",
+  ])("tolerates %s correlation without deleting any echo", (kind) => {
+    const f = fixture();
+    f.store.send("hello", images);
+    f.store.handleDelta({
+      type: "chat.queued",
+      conversationId: kind === "wrong-conversation" ? "c2" : "c1",
+      reason: "compaction",
+      messageId: "q1",
+      ...(kind === "missing" ? {} : { requestId: kind === "unknown" ? "r999" : "r1" }),
+    });
+    expect(f.store.chunks).toHaveLength(3);
+    expect(f.store.error).toBeNull();
+    f.store.dispose();
+  });
+
+  it.each([
+    false,
+    true,
+  ])("preserves a live confirmed prompt before delayed ack (batched=%s)", (batched) => {
+    const f = fixture(batched);
+    f.store.send("hello", images);
+    f.start("hello");
+    f.event({ type: "text-delta", conversationId: "c1", turnId: "t1", delta: "answer" });
+    f.ack();
+    f.ack();
+    for (const flush of f.scheduled) flush();
+    expect(f.store.chunks.map((c) => c.chunk)).toEqual([
+      { type: "text", text: "hello" },
+      { type: "text", text: "answer" },
+    ]);
+    expect(f.store.generating).toBe(true);
+    expect(f.store.error).toBeNull();
+    f.store.dispose();
+  });
+
+  it("turn-start tagging alone does not protect a still-local echo", () => {
+    const f = fixture(true);
+    f.store.send("hello", images);
+    f.start();
+    f.ack();
+    expect(f.store.chunks).toEqual([]);
+    expect(f.store.generating).toBe(true);
+    f.event({ type: "user-message", conversationId: "c1", turnId: "t1", text: "hello" });
+    for (const flush of f.scheduled) flush();
+    expect(f.store.chunks.map((c) => c.chunk)).toEqual([{ type: "text", text: "hello" }]);
+    f.store.dispose();
+  });
+
+  it("keeps a combined queue opening and steering; removes only the original individual echoes", () => {
+    const f = fixture(true);
+    f.store.send("one", images);
+    f.store.send("two", images);
+    f.start("one\n\ntwo");
+    f.event({ type: "steering", conversationId: "c1", turnId: "t1", text: "steer" });
+    f.ack("r2");
+    f.ack("r1");
+    expect(f.store.chunks.map((c) => c.chunk)).toEqual([
+      { type: "text", text: "one\n\ntwo" },
+      { type: "text", text: "steer" },
+    ]);
+    expect(f.store.generating).toBe(true);
+    f.store.dispose();
+  });
+
+  it.each([
+    "ack-first",
+    "reset-first",
+    "history-first",
+  ])("handles epoch replacement idempotently: %s", async (order) => {
+    const f = fixture();
+    await f.store.load();
+    f.store.send("hello", images);
+    if (order === "ack-first") f.ack();
+    f.history.historyEpoch = 1;
+    f.history.returnChunks = [
+      { seq: 1, role: "user", turnId: "t1", chunk: { type: "text", text: "hello" } },
+      { seq: 2, role: "user", turnId: "t1", chunk: { type: "image", url: "/images/c1/saved.png" } },
+    ];
+    f.store.resync(1);
+    if (order === "reset-first") f.ack();
+    await vi.waitFor(() => expect(f.store.pendingSync).toBe(false));
+    f.start("hello");
+    const before = f.store.chunks;
+    f.ack();
+    f.ack();
+    expect(f.store.chunks).toEqual(before);
+    expect(f.store.chunks.map((c) => c.chunk)).toEqual(f.history.returnChunks.map((c) => c.chunk));
+    expect(f.store.generating).toBe(true);
+    expect(f.store.error).toBeNull();
+    expect(f.transport.sent).toHaveLength(1);
+    f.store.dispose();
+  });
+
+  it("keeps normal immediate-send text/image deduplication and authoritative history", async () => {
+    const f = fixture();
+    f.store.send("hello", images);
+    f.start("hello");
+    expect(f.store.chunks).toHaveLength(3);
+    f.history.returnChunks = [
+      { seq: 1, role: "user", turnId: "t1", chunk: { type: "text", text: "hello" } },
+      { seq: 2, role: "user", turnId: "t1", chunk: { type: "image", url: "/images/c1/saved.png" } },
+    ];
+    f.event({ type: "turn-sealed", conversationId: "c1", turnId: "t1" });
+    await vi.waitFor(() => expect(f.store.pendingSync).toBe(false));
+    expect(f.store.chunks.map((c) => c.chunk)).toEqual(f.history.returnChunks.map((c) => c.chunk));
+    expect(f.store.chunks.every((c) => !c.provisional)).toBe(true);
+    expect(f.transport.sent).toHaveLength(1);
+    f.store.dispose();
+  });
+});
diff --git a/src/features/chat/store.svelte.ts b/src/features/chat/store.svelte.ts
index f48d441..66ee5ee 100644
--- a/src/features/chat/store.svelte.ts
+++ b/src/features/chat/store.svelte.ts
@@ -2,6 +2,7 @@ import type {
   ChatDeltaMessage,
   ChatErrorMessage,
   ChatQueueCancelMessage,
+  ChatQueuedMessage,
   ChatQueueMessage,
   ChatSendMessage,
 } from "@dispatch/transport-contract";
@@ -15,6 +16,7 @@ import {
   initialState,
   initialWindowSize,
   normalizeChatLimit,
+  removeLocalEcho,
   restoreEarlier,
   selectChunks,
   selectGenerating,
@@ -43,6 +45,8 @@ import type { ChatTransport, HistorySync, MetricsSync } from "./ports";
 
 export interface ChatStoreDependencies {
   readonly conversationId: string;
+  /** Injected unique client-local correlation token for each new send. */
+  readonly createRequestId: () => string;
   readonly model?: string;
   readonly transport: ChatTransport;
   readonly historySync: HistorySync;
@@ -142,7 +146,7 @@ export interface ChatStore {
    * Ignored while a turn is generating; a running turn gap keeps the later start.
    */
   noteLastActivity(at: number): void;
-  handleDelta(msg: ChatDeltaMessage | ChatErrorMessage): void;
+  handleDelta(msg: ChatDeltaMessage | ChatErrorMessage | ChatQueuedMessage): void;
   /**
    * Send a user message (start a turn via `chat.send`). Optimistically echoes
    * the text + any `images` as provisional user chunks (`[text, image, …]` in
@@ -540,7 +544,7 @@ export function createChatStore(deps: ChatStoreDependencies): ChatStore {
       cacheTimer = seedTurnGap(cacheTimer, at);
     },
 
-    handleDelta(msg: ChatDeltaMessage | ChatErrorMessage): void {
+    handleDelta(msg: ChatDeltaMessage | ChatErrorMessage | ChatQueuedMessage): void {
       if (msg.type === "chat.error") {
         if (msg.conversationId !== undefined && msg.conversationId !== deps.conversationId) {
           return;
@@ -548,6 +552,14 @@ export function createChatStore(deps: ChatStoreDependencies): ChatStore {
         _error = msg.message;
         return;
       }
+      if (msg.type === "chat.queued") {
+        if (disposed || msg.conversationId !== deps.conversationId) return;
+        // A queued live opening may already have confirmed the echoed text.
+        // Fold it first; turn-start alone must not protect still-local artifacts.
+        flushEvents();
+        if (msg.requestId !== undefined) transcript = removeLocalEcho(transcript, msg.requestId);
+        return;
+      }
       if (msg.event.conversationId !== deps.conversationId) {
         return;
       }
@@ -566,10 +578,12 @@ export function createChatStore(deps: ChatStoreDependencies): ChatStore {
       flushEvents();
       // Sending ends the wait since the last turn: stamp it on that turn.
       cacheTimer = stopTurnGap(cacheTimer, now(), () => lastTurnIdOf(metrics));
-      transcript = appendUserMessage(transcript, text, images);
+      const requestId = deps.createRequestId();
+      transcript = appendUserMessage(transcript, text, images, requestId);
       maybeTrim();
       const msg: ChatSendMessage = {
         type: "chat.send",
+        requestId,
         conversationId: deps.conversationId,
         message: text,
         ...(_model !== undefined ? { model: _model } : {}),
diff --git a/src/features/chat/store.test.ts b/src/features/chat/store.test.ts
index de84b8a..c24592d 100644
--- a/src/features/chat/store.test.ts
+++ b/src/features/chat/store.test.ts
@@ -32,6 +32,7 @@ describe("createChatStore", () => {
     const metricsSync = createFakeMetricsSync();
     const cache = createFakeCache();
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -64,6 +65,7 @@ describe("createChatStore", () => {
     const metricsSync = createFakeMetricsSync();
     const cache = createFakeCache();
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -107,6 +109,7 @@ describe("createChatStore", () => {
     const metricsSync = createFakeMetricsSync();
     const cache = createFakeCache();
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -131,6 +134,7 @@ describe("createChatStore", () => {
     const metricsSync = createFakeMetricsSync();
     const cache = createFakeCache();
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       model: "openai/gpt-4",
       transport: transport.impl,
@@ -153,6 +157,7 @@ describe("createChatStore", () => {
     const metricsSync = createFakeMetricsSync();
     const cache = createFakeCache();
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -185,6 +190,7 @@ describe("createChatStore", () => {
   it("send omits images on the wire when none are staged (backward compatible)", () => {
     const transport = createFakeTransport();
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: createFakeHistorySync().impl,
@@ -201,6 +207,7 @@ describe("createChatStore", () => {
   it("send omits images on the wire for an empty array", () => {
     const transport = createFakeTransport();
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: createFakeHistorySync().impl,
@@ -217,6 +224,7 @@ describe("createChatStore", () => {
   it("send allows an images-only message (empty text)", () => {
     const transport = createFakeTransport();
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: createFakeHistorySync().impl,
@@ -241,6 +249,7 @@ describe("createChatStore", () => {
       const metricsSync = createFakeMetricsSync();
       const cache = createFakeCache();
       const store = createChatStore({
+        createRequestId: () => crypto.randomUUID(),
         conversationId: CONV_ID,
         transport: transport.impl,
         historySync: historySync.impl,
@@ -263,6 +272,7 @@ describe("createChatStore", () => {
     it.each(["  describe this  ", "", "   "])("queues images with text %j", (text) => {
       const transport = createFakeTransport();
       const store = createChatStore({
+        createRequestId: () => crypto.randomUUID(),
         conversationId: CONV_ID,
         workspaceId: "images-workspace",
         transport: transport.impl,
@@ -298,6 +308,7 @@ describe("createChatStore", () => {
       const metricsSync = createFakeMetricsSync();
       const cache = createFakeCache();
       const store = createChatStore({
+        createRequestId: () => crypto.randomUUID(),
         conversationId: CONV_ID,
         transport: transport.impl,
         historySync: historySync.impl,
@@ -318,6 +329,7 @@ describe("createChatStore", () => {
       const metricsSync = createFakeMetricsSync();
       const cache = createFakeCache();
       const store = createChatStore({
+        createRequestId: () => crypto.randomUUID(),
         conversationId: CONV_ID,
         transport: transport.impl,
         historySync: historySync.impl,
@@ -340,6 +352,7 @@ describe("createChatStore", () => {
       const metricsSync = createFakeMetricsSync();
       const cache = createFakeCache();
       const store = createChatStore({
+        createRequestId: () => crypto.randomUUID(),
         conversationId: CONV_ID,
         transport: transport.impl,
         historySync: historySync.impl,
@@ -362,6 +375,7 @@ describe("createChatStore", () => {
       const metricsSync = createFakeMetricsSync();
       const cache = createFakeCache();
       const store = createChatStore({
+        createRequestId: () => crypto.randomUUID(),
         conversationId: CONV_ID,
         transport: transport.impl,
         historySync: historySync.impl,
@@ -387,6 +401,7 @@ describe("createChatStore", () => {
       const metricsSync = createFakeMetricsSync();
       const cache = createFakeCache();
       const store = createChatStore({
+        createRequestId: () => crypto.randomUUID(),
         conversationId: CONV_ID,
         transport: transport.impl,
         historySync: historySync.impl,
@@ -408,6 +423,7 @@ describe("createChatStore", () => {
       const metricsSync = createFakeMetricsSync();
       const cache = createFakeCache();
       const store = createChatStore({
+        createRequestId: () => crypto.randomUUID(),
         conversationId: CONV_ID,
         transport: transport.impl,
         historySync: historySync.impl,
@@ -433,6 +449,7 @@ describe("createChatStore", () => {
     const metricsSync = createFakeMetricsSync();
     const cache = createFakeCache();
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -462,6 +479,7 @@ describe("createChatStore", () => {
     historySync.returnChunks = [makeStoredChunk(3, "assistant")];
 
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -490,6 +508,7 @@ describe("createChatStore", () => {
     historySync.returnChunks = [makeStoredChunk(1, "assistant")];
 
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -511,6 +530,7 @@ describe("createChatStore", () => {
     const metricsSync = createFakeMetricsSync();
     const cache = createFakeCache();
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -543,6 +563,7 @@ describe("createChatStore", () => {
     const metricsSync = createFakeMetricsSync();
     const cache = createFakeCache();
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -587,6 +608,7 @@ describe("createChatStore", () => {
     };
 
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: slowHistorySync,
@@ -621,6 +643,7 @@ describe("createChatStore", () => {
     const metricsSync = createFakeMetricsSync();
     const cache = createFakeCache();
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -666,6 +689,7 @@ describe("createChatStore", () => {
     const metricsSync = createFakeMetricsSync();
     const cache = createFakeCache();
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       model: "openai/gpt-4",
       transport: transport.impl,
@@ -690,6 +714,7 @@ describe("createChatStore", () => {
     const metricsSync = createFakeMetricsSync();
     const cache = createFakeCache();
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -713,6 +738,7 @@ describe("createChatStore", () => {
     const metricsSync = createFakeMetricsSync();
     const cache = createFakeCache();
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -743,6 +769,7 @@ describe("createChatStore", () => {
     const metricsSync = createFakeMetricsSync();
     const cache = createFakeCache();
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -763,6 +790,7 @@ describe("createChatStore", () => {
     const metricsSync = createFakeMetricsSync();
     const cache = createFakeCache();
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -787,6 +815,7 @@ describe("createChatStore", () => {
     const metricsSync = createFakeMetricsSync();
     const cache = createFakeCache();
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -825,6 +854,7 @@ describe("createChatStore", () => {
     const metricsSync = createFakeMetricsSync();
     const cache = createFakeCache();
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -886,6 +916,7 @@ describe("createChatStore", () => {
     const metricsSync = createFakeMetricsSync();
     const cache = createFakeCache();
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -930,6 +961,7 @@ describe("createChatStore", () => {
     const metricsSync = createFakeMetricsSync();
     const cache = createFakeCache();
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -1002,6 +1034,7 @@ describe("createChatStore", () => {
     const metricsSync = createFakeMetricsSync();
     const cache = createFakeCache();
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -1068,6 +1101,7 @@ describe("createChatStore", () => {
     ];
 
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -1092,6 +1126,7 @@ describe("createChatStore", () => {
     const metricsSync = createFakeMetricsSync();
     const cache = createFakeCache();
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -1123,6 +1158,7 @@ describe("createChatStore", () => {
     const metricsSync = createFakeMetricsSync();
     const cache = createFakeCache();
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -1147,6 +1183,7 @@ describe("createChatStore", () => {
     const metricsSync = createFakeMetricsSync();
     const cache = createFakeCache();
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -1181,6 +1218,7 @@ describe("createChatStore", () => {
     const metricsSync = createFakeMetricsSync();
     const cache = createFakeCache();
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -1227,6 +1265,7 @@ describe("createChatStore", () => {
     const cache = createFakeCache();
     let atBottom = false; // reader scrolled up
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -1281,6 +1320,7 @@ describe("createChatStore", () => {
     const cache = createFakeCache();
     let atBottom = false;
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -1319,6 +1359,7 @@ describe("createChatStore", () => {
     );
 
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -1348,6 +1389,7 @@ describe("createChatStore", () => {
     historySync.returnChunks = Array.from({ length: 500 }, (_, i) => makeStoredChunk(i + 1));
 
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -1383,6 +1425,7 @@ describe("createChatStore", () => {
     historySync.returnChunks = [makeStoredChunk(3)];
 
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -1407,6 +1450,7 @@ describe("createChatStore", () => {
     historySync.returnChunks = Array.from({ length: 500 }, (_, i) => makeStoredChunk(i + 1));
 
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -1444,6 +1488,7 @@ describe("createChatStore", () => {
     );
 
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -1476,6 +1521,7 @@ describe("createChatStore", () => {
     );
 
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -1507,6 +1553,7 @@ describe("createChatStore", () => {
     );
 
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -1539,6 +1586,7 @@ describe("createChatStore", () => {
     const metricsSync = createFakeMetricsSync();
     const cache = createFakeCache();
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -1576,6 +1624,7 @@ describe("createChatStore", () => {
       Array.from({ length: 200 }, (_, i) => makeStoredChunk(i + 1)),
     );
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -1607,6 +1656,7 @@ describe("createChatStore", () => {
     // Server holds 200; cold-cache load at limit 100 → window 75 → seqs 126..200.
     historySync.returnChunks = Array.from({ length: 200 }, (_, i) => makeStoredChunk(i + 1));
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -1634,6 +1684,7 @@ describe("createChatStore", () => {
     const metricsSync = createFakeMetricsSync();
     const cache = createFakeCache();
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -1673,6 +1724,7 @@ describe("createChatStore", () => {
       Array.from({ length: 50 }, (_, i) => makeStoredChunk(i + 1)),
     );
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -1700,6 +1752,7 @@ describe("createChatStore", () => {
     const metricsSync = createFakeMetricsSync();
     const cache = createFakeCache();
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -1729,6 +1782,7 @@ describe("createChatStore", () => {
     const metricsSync = createFakeMetricsSync();
     const cache = createFakeCache();
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: transport.impl,
       historySync: historySync.impl,
@@ -1750,6 +1804,7 @@ describe("createChatStore — batched delta application (scheduleFlush)", () =>
     const scheduled: (() => void)[] = [];
     const historySync = createFakeHistorySync();
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: createFakeTransport().impl,
       historySync: historySync.impl,
@@ -1831,6 +1886,7 @@ describe("createChatStore — batched delta application (scheduleFlush)", () =>
 describe("createChatStore — cacheTimer", () => {
   function makeStore(now: () => number) {
     return createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: createFakeTransport().impl,
       historySync: createFakeHistorySync().impl,
@@ -1940,6 +1996,7 @@ describe("history epochs", () => {
     const cache = createFakeCache();
     history.returnChunks = Array.from({ length: 20 }, (_, i) => makeStoredChunk(i + 1));
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: createFakeTransport().impl,
       historySync: history.impl,
@@ -1980,6 +2037,7 @@ it("a compaction broadcast during an in-flight fetch discards the old response",
     .mockImplementation(history.impl);
   const cache = createFakeCache();
   const store = createChatStore({
+    createRequestId: () => crypto.randomUUID(),
     conversationId: CONV_ID,
     transport: createFakeTransport().impl,
     historySync: sync,
@@ -2006,6 +2064,7 @@ it("reloads unknown legacy cache epochs rather than merging pre-upgrade rows", a
   const history = createFakeHistorySync();
   history.returnChunks = [makeStoredChunk(101)];
   const store = createChatStore({
+    createRequestId: () => crypto.randomUUID(),
     conversationId: CONV_ID,
     transport: createFakeTransport().impl,
     historySync: history.impl,
@@ -2037,6 +2096,7 @@ describe("server epoch rollback", () => {
     const history = createFakeHistorySync();
     history.historyEpoch = 5;
     const store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: createFakeTransport().impl,
       historySync: history.impl,
@@ -2083,6 +2143,7 @@ describe("server epoch rollback", () => {
       return { chunks: [], latestSeq: 0, historyEpoch: calls - 1 };
     };
     store = createChatStore({
+      createRequestId: () => crypto.randomUUID(),
       conversationId: CONV_ID,
       transport: createFakeTransport().impl,
       historySync: sync,
@@ -2140,6 +2201,7 @@ it.each([
     };
   });
   const store = createChatStore({
+    createRequestId: () => crypto.randomUUID(),
     conversationId: CONV_ID,
     transport: createFakeTransport().impl,
     historySync: sync,
@@ -2182,6 +2244,7 @@ it("replaces an empty high-epoch cache with the server's empty lower epoch in on
   await cache.reset(CONV_ID, 8);
   const history = createFakeHistorySync();
   const store = createChatStore({
+    createRequestId: () => crypto.randomUUID(),
     conversationId: CONV_ID,
     transport: createFakeTransport().impl,
     historySync: history.impl,