diff --git a/.project-docs/30-worklog/tasks/20260823-pi-chat-timeline-c8f31a62.md b/.project-docs/30-worklog/tasks/20260823-pi-chat-timeline-c8f31a62.md
index 69e2df0..e09f148 100644
--- a/.project-docs/30-worklog/tasks/20260823-pi-chat-timeline-c8f31a62.md
+++ b/.project-docs/30-worklog/tasks/20260823-pi-chat-timeline-c8f31a62.md
@@ -130,24 +130,60 @@
   buffers during target recovery, trims Snapshot-covered items and replays only
   a strict continuous tail.
 - Fixed a supported concurrency defect exposed by the full suite: the Pi
-  Session Registry now reuses one Conversation store per project, serializing
-  simultaneous first bindings instead of racing writes to the same metadata
-  file.
+  Session Registry and Coding Project Service now receive the same project-
+  scoped Conversation store provider, so runtime bindings and metadata writes
+  serialize through one mutation queue instead of racing the same file.
+- Closed the first planner review findings after candidate `612135f`: the
+  authenticated Host server now admits only the exact image-binary upload
+  exception; empty/invalid/oversize/not-found attachments have stable typed
+  errors and supported image signatures are checked before disk writes.
+- Made active target ownership atomic across Agent switches. An old or archived
+  Conversation cannot supply the visible draft/timeline/prompt target, and a
+  slow automatic or explicit create completion only selects when its captured
+  project and Agent are still active. Submission flights and errors are scoped
+  per Conversation, so one pending/rejected target does not disable another.
+- Bounded each message to 16 local images and four concurrent uploads. A real
+  Electron image fixture now traverses the Renderer facade, IPC channel and
+  authenticated Host server, reads the stored bytes back for the optimistic
+  timeline preview, observes one upload, and verifies the prompt contains only
+  attachment ids rather than base64.
+- Extended target-only gap recovery: when the first recovery Snapshot remains
+  behind a buffered continuous tail, Renderer requests one fresh target
+  Snapshot; a repeated identical stale response becomes a retryable error
+  instead of remaining in an infinite recovering state.
 - Synchronized `README.md` with the current Pi core Chat, first-Conversation,
   batch and attachment behavior. PI-130 feature controls and PI-140 legacy
   removal remain outside this task.
 
 ## Verification
 
-- `pnpm exec vitest run tests/unit/coding-workspace-store.test.ts tests/unit/coding-projects-facade.test.ts tests/unit/coding-attachments-facade.test.ts tests/unit/coding-attachments-routes.test.ts tests/unit/coding-chat-panel.test.tsx tests/unit/coding-conversation-timeline.test.tsx tests/unit/coding-conversations-store.test.tsx tests/unit/coding-core-routes.test.ts tests/unit/host-api.test.ts tests/unit/host-api-proxy.test.ts`: passed, 10 files / 68 tests before the final malformed-batch and Session Registry regression additions.
-- `pnpm exec vitest run tests/unit/pi-session-registry.test.ts tests/unit/pi-conversation-runtime.test.ts tests/unit/coding-conversations-store.test.tsx tests/unit/coding-chat-panel.test.tsx`: passed, 4 files / 25 tests.
-- `pnpm test`: passed, 217 files / 2303 passed / 2 skipped. The final run is green after fixing the same-project parallel Session Registry write race and stabilizing the AI Hardware async query at its actual loading boundary.
+- First implementation candidate `612135f` received planner review result
+  **Standards Needs Fix / Spec Needs Fix**. PI-120 remained the unique Ready
+  Frontier; the findings above were treated as blocking rather than advancing
+  PI-130.
+- Post-review focused suites passed: attachment Host routes, stale recovery,
+  shared ProjectService/Registry mutation queue, slow Agent switch, cross-
+  Conversation submission isolation, attachment count/concurrency and pressure
+  tests all pass. The consolidated focused run covered 3 files / 30 tests, and
+  `coding-chat-panel.test.tsx` covered 6/6 behavior tests.
+- `REN-008` actual-path fixture passed with 100 runtime patch items, 20 public
+  patch batches, 21 SSE frames including Snapshot, 20 Renderer transactions,
+  20 React commits, 131,148 wire bytes, and measured Main-to-React p95
+  `35.995 ms` against the `<=50 ms` budget. It includes mixed message blocks,
+  4 KiB tool output and more than 100 KiB of cumulative thinking output.
+- `pnpm test`: passed, 218 files / 2316 passed / 2 skipped.
 - `pnpm run typecheck`: passed.
-- `pnpm run lint:check`: passed with 0 errors and six unchanged warnings in `ExecutionGraphCard`, `Home`, and `Makelore`.
-- `pnpm run build:vite`: passed; existing Vite dynamic-import and chunk-size warnings remain.
-- `pnpm exec playwright test tests/e2e/pi-coding-first-chat.spec.ts`: passed, 1/1.
-- `pnpm exec playwright test tests/e2e/pi-coding-first-chat.spec.ts --repeat-each=20 --workers=1`: passed, 20/20 fresh-userData runs. Every sample asserted Composer editability below 500 ms while runtime Snapshot was held, so the measured sample p95 is below the locked 500 ms budget; the same fixture verifies optimistic prompt visibility and HTTP 202 acceptance without a real Provider.
-- `git diff --check`: passed; only repository line-ending conversion notices were printed.
+- `pnpm run lint:check`: passed with 0 errors and six unchanged warnings in
+  `ExecutionGraphCard`, `Home`, and `Makelore`.
+- `pnpm run build:vite`: passed; existing Vite dynamic-import and chunk-size
+  warnings remain.
+- `pnpm exec playwright test tests/e2e/pi-coding-first-chat.spec.ts`: passed,
+  1/1. The post-review real-image fixture also passed 5/5 fresh-userData repeats
+  with one upload, Host readback preview, optimistic message, HTTP 202 and no
+  base64 in later payloads. The earlier text-only first-Conversation fixture
+  passed 20/20 fresh-userData runs below the 500 ms editability budget.
+- `git diff --check`: passed; only repository line-ending conversion notices
+  were printed.
 - Real Provider remains **Explicitly Waived / Accepted Risk** with
   `realTurnVerified=false`; no Provider Account, credential isolation,
   protocol-specific endpoint, rate-limit or real concurrency behavior is
diff --git a/README.md b/README.md
index 63c6c50..a5200f4 100644
--- a/README.md
+++ b/README.md
@@ -128,7 +128,7 @@ Windows 打包脚本会先准备目标架构所需的 Python、uv 与 OpenCode 
 - 核心聊天页左侧按伙伴展示本地 Conversation，并提供新建入口；首次选择没有 Conversation 的伙伴时立即创建本地元数据，同时异步准备对应运行时。即使准备被阻塞或超时，输入框仍可编辑，草稿也不会丢失。
 - Conversation 历史按需从 Main-owned Snapshot 读取。公开 SSE 只交付 Snapshot 与按 Conversation、worker generation 分组的 `patch-batch`；Renderer 整批校验连续 seq 后在一次状态事务中顺序应用，缺口或畸形批次只恢复目标 Conversation，隐藏 Conversation 的流式更新不会提交选中时间线。
 - 核心时间线渲染消息、Markdown、thinking、工具、压缩、轮次边界和通知；默认保留最近 120 个节点的渲染窗口，可按 100 个节点加载更早内容。工具累计输出覆盖同一块而不重复追加。
-- Composer 支持文字、粘贴或选择 PNG/JPEG/WebP/GIF 图片。图片在发送前只保留本地预览，点击发送时才经 Main-owned 有界二进制接口上传一次；状态与事件只保存 attachment id，时间线按需读取二进制并创建临时 object URL，不保存重复 base64。
+- Composer 支持文字、粘贴或选择 PNG/JPEG/WebP/GIF 图片，每条消息最多 16 张、最多并行上传 4 张。图片在发送前只保留本地预览，点击发送时才经 Main-owned 有界二进制接口上传一次；Main 在落盘前核对 MIME 与最小图片签名，状态与事件只保存 attachment id，时间线按需读取二进制并创建临时 object URL，不保存重复 base64。
 - Makelore 在应用侧按 Session 独立提交、跟踪和隔离运行状态，不使用“当前对话正在回复”的全局界面锁；同一 Session 的后续消息仍按顺序排队。共享 runtime/provider 是否真正并发执行不同 Session 尚未经过自动化真实运行 smoke 验证，运行时仍可能自行串行、限流或拒绝请求。
 - 首次发送会立即生成稳定的乐观用户消息；HTTP 202 只表示本地 Agent 已接收。后续失败不会删除已接受消息，不确定交付不会自动重发；准备失败可在目标 Conversation 上手动恢复。
 - 归档、分支、标题、未读、模型/thinking、队列、交互、子任务、changes/files/browser/skills/commands 等完整 Conversation 操作当前不属于核心聊天页。
diff --git a/electron/api/coding-composition.ts b/electron/api/coding-composition.ts
index ba6c9c7..2f59c53 100644
--- a/electron/api/coding-composition.ts
+++ b/electron/api/coding-composition.ts
@@ -81,7 +81,18 @@ export function createCodingComposition(
   });
   const extensionHost = new PiManagedExtensionHost();
   extensionHost.configureProductTools(productTools);
-  const registry = new PiSessionRegistry({ projectStore });
+  const conversationStores = new Map<string, ReturnType<typeof createCodingConversationStore>>();
+  const conversationStoreForProject = (projectPath: string) => {
+    const existing = conversationStores.get(projectPath);
+    if (existing) return existing;
+    const created = createCodingConversationStore(projectPath);
+    conversationStores.set(projectPath, created);
+    return created;
+  };
+  const registry = new PiSessionRegistry({
+    projectStore,
+    createConversationStore: conversationStoreForProject,
+  });
   const revisions = new PiManagedInputRevisionCoordinator();
   const processBudget = new PiProcessBudget();
   const loadProviderInput = async () => ({
@@ -145,15 +156,16 @@ export function createCodingComposition(
     })),
   });
   const projects = new CodingProjectService(projectStore, {
+    createConversationStore: conversationStoreForProject,
     onResourcesChanged: async (project) => {
       runtime.markResourcesStale();
-      const conversations = await createCodingConversationStore(project.path).read()
+      const conversations = await conversationStoreForProject(project.path).read()
         .then((file) => file.conversations)
         .catch(() => []);
       for (const conversation of conversations) registry.forget(conversation.id);
     },
     onProjectDeactivated: async (project) => {
-      const conversations = await createCodingConversationStore(project.path).read()
+      const conversations = await conversationStoreForProject(project.path).read()
         .then((file) => file.conversations)
         .catch(() => []);
       await Promise.allSettled([
diff --git a/electron/api/routes/coding-attachments.ts b/electron/api/routes/coding-attachments.ts
index 1eeb755..4dee2a3 100644
--- a/electron/api/routes/coding-attachments.ts
+++ b/electron/api/routes/coding-attachments.ts
@@ -3,6 +3,7 @@ import type { HostApiContext } from '../context';
 import { sendJson } from '../route-utils';
 
 const MAX_ATTACHMENT_BYTES = 16 * 1024 * 1024;
+const ATTACHMENT_ID_PATTERN = /^[A-Za-z0-9-]{1,64}$/;
 const SUPPORTED_IMAGE_MIMES = new Set([
   'image/png',
   'image/jpeg',
@@ -10,6 +11,37 @@ const SUPPORTED_IMAGE_MIMES = new Set([
   'image/gif',
 ]);
 
+function matchesImageSignature(data: Uint8Array, mime: string): boolean {
+  if (mime === 'image/png') {
+    return data.length >= 8
+      && data[0] === 0x89
+      && data[1] === 0x50
+      && data[2] === 0x4e
+      && data[3] === 0x47
+      && data[4] === 0x0d
+      && data[5] === 0x0a
+      && data[6] === 0x1a
+      && data[7] === 0x0a;
+  }
+  if (mime === 'image/jpeg') {
+    return data.length >= 3
+      && data[0] === 0xff
+      && data[1] === 0xd8
+      && data[2] === 0xff;
+  }
+  if (mime === 'image/gif') {
+    if (data.length < 6) return false;
+    const header = Buffer.from(data.subarray(0, 6)).toString('ascii');
+    return header === 'GIF87a' || header === 'GIF89a';
+  }
+  if (mime === 'image/webp') {
+    return data.length >= 12
+      && Buffer.from(data.subarray(0, 4)).toString('ascii') === 'RIFF'
+      && Buffer.from(data.subarray(8, 12)).toString('ascii') === 'WEBP';
+  }
+  return false;
+}
+
 function contentType(req: IncomingMessage): string {
   const value = req.headers['content-type'];
   return (Array.isArray(value) ? value[0] : value)?.split(';', 1)[0]?.trim().toLowerCase() ?? '';
@@ -17,7 +49,7 @@ function contentType(req: IncomingMessage): string {
 
 async function readBoundedBody(req: IncomingMessage): Promise<Uint8Array> {
   const declared = Number(req.headers['content-length']);
-  if (Number.isFinite(declared) && (declared <= 0 || declared > MAX_ATTACHMENT_BYTES)) {
+  if (Number.isFinite(declared) && declared > MAX_ATTACHMENT_BYTES) {
     throw Object.assign(new Error('Attachment size is invalid'), { status: 413 });
   }
   const chunks: Buffer[] = [];
@@ -86,12 +118,24 @@ export async function handleCodingAttachmentRoutes(
       if (!SUPPORTED_IMAGE_MIMES.has(mime)) {
         throw Object.assign(new Error('Attachment MIME is invalid'), { status: 400 });
       }
-      const attachment = await attachments.put(await readBoundedBody(req), mime);
+      const body = await readBoundedBody(req);
+      if (!matchesImageSignature(body, mime)) {
+        throw Object.assign(new Error('Attachment body is not the declared image type'), { status: 400 });
+      }
+      const attachment = await attachments.put(body, mime);
       sendJson(res, 201, attachment);
       return true;
     }
 
-    const attachmentId = decodeURIComponent(contentMatch?.[1] ?? '');
+    let attachmentId: string;
+    try {
+      attachmentId = decodeURIComponent(contentMatch?.[1] ?? '');
+    } catch {
+      throw Object.assign(new Error('Attachment id is invalid'), { status: 400 });
+    }
+    if (!ATTACHMENT_ID_PATTERN.test(attachmentId)) {
+      throw Object.assign(new Error('Attachment id is invalid'), { status: 400 });
+    }
     const record = await attachments.read(attachmentId);
     if (!SUPPORTED_IMAGE_MIMES.has(record.mime)) {
       throw Object.assign(new Error('Attachment MIME is invalid'), { status: 400 });
diff --git a/electron/api/server.ts b/electron/api/server.ts
index 094410e..d271b2a 100644
--- a/electron/api/server.ts
+++ b/electron/api/server.ts
@@ -56,9 +56,12 @@ export function startHostApiServer(ctx: HostApiContext, port = getPort('NIANCODE
       }
 
       // ── Content-Type gate (anti-CSRF) ──────────────────────────
-      // Mutation requests must use application/json to force a CORS
-      // preflight, preventing "simple request" CSRF attacks.
-      if (!requireJsonContentType(req)) {
+      // Mutation requests use application/json, except the exact authenticated
+      // image-byte upload route. Its supported image MIME types also force a
+      // browser preflight and are validated before storage.
+      const isCodingAttachmentUpload = req.method === 'POST'
+        && requestUrl.pathname === '/api/coding/attachments';
+      if (!isCodingAttachmentUpload && !requireJsonContentType(req)) {
         sendJson(res, 415, { success: false, error: 'Content-Type must be application/json' });
         return;
       }
diff --git a/electron/coding-projects/project-service.ts b/electron/coding-projects/project-service.ts
index eea87db..d159128 100644
--- a/electron/coding-projects/project-service.ts
+++ b/electron/coding-projects/project-service.ts
@@ -56,6 +56,7 @@ export interface CodingProjectConfigSnapshot {
 export interface CodingProjectServiceOptions {
   onResourcesChanged?(project: CodingProject): Promise<void> | void;
   onProjectDeactivated?(project: CodingProject): Promise<void> | void;
+  createConversationStore?: typeof createCodingConversationStore;
   writeConfig?: typeof writeCodingProjectConfigV2;
 }
 
@@ -299,7 +300,7 @@ export class CodingProjectService {
   conversationStore(projectPath: string): ReturnType<typeof createCodingConversationStore> {
     const existing = this.conversationStores.get(projectPath);
     if (existing) return existing;
-    const created = createCodingConversationStore(projectPath);
+    const created = (this.options.createConversationStore ?? createCodingConversationStore)(projectPath);
     this.conversationStores.set(projectPath, created);
     return created;
   }
diff --git a/src/lib/coding-attachments.ts b/src/lib/coding-attachments.ts
index 13d8631..229baa9 100644
--- a/src/lib/coding-attachments.ts
+++ b/src/lib/coding-attachments.ts
@@ -1,6 +1,8 @@
 import { hostApiFetch, hostApiFetchBytes } from './host-api';
 
 export const CODING_ATTACHMENT_MAX_BYTES = 16 * 1024 * 1024;
+export const CODING_ATTACHMENT_MAX_COUNT = 16;
+export const CODING_ATTACHMENT_UPLOAD_CONCURRENCY = 4;
 export const CODING_ATTACHMENT_MIMES = new Set([
   'image/png',
   'image/jpeg',
diff --git a/src/pages/Chat/CodingChatPanel.tsx b/src/pages/Chat/CodingChatPanel.tsx
index 88c14a8..749688c 100644
--- a/src/pages/Chat/CodingChatPanel.tsx
+++ b/src/pages/Chat/CodingChatPanel.tsx
@@ -10,7 +10,9 @@ import {
 import { Button } from '@/components/ui/button';
 import {
   CODING_ATTACHMENT_MAX_BYTES,
+  CODING_ATTACHMENT_MAX_COUNT,
   CODING_ATTACHMENT_MIMES,
+  CODING_ATTACHMENT_UPLOAD_CONCURRENCY,
   uploadCodingAttachment,
   type CodingAttachmentRef,
 } from '@/lib/coding-attachments';
@@ -23,7 +25,7 @@ import {
   useCodingConversationStore,
   type CodingConversationStoreState,
 } from '@/stores/coding-conversations';
-import { useCodingWorkspaceStore } from '@/stores/coding-workspace';
+import { codingWorkspaceStore, useCodingWorkspaceStore } from '@/stores/coding-workspace';
 import type {
   CodingDraftAttachment,
 } from '@/types/coding-conversation';
@@ -66,6 +68,7 @@ function requestCount(
 }
 
 const BLOCKING_REQUEST_STATUSES = new Set(['pending', 'accepted']);
+const SUBMITTING_REQUEST_STATUSES = new Set(['pending']);
 const ACCEPTED_REQUEST_STATUSES = new Set(['accepted']);
 const UNCERTAIN_REQUEST_STATUSES = new Set(['uncertain']);
 
@@ -96,10 +99,8 @@ export function CodingChatPanel({
   const submitPrompt = useCodingConversationStore((state) => state.submitPrompt);
   const recoverConversation = useCodingConversationStore((state) => state.recoverConversation);
 
-  const [provisionalDraft, setProvisionalDraft] = useState('');
-  const [creatingNewConversation, setCreatingNewConversation] = useState(false);
-  const [submitting, setSubmitting] = useState(false);
-  const [submissionError, setSubmissionError] = useState<string | null>(null);
+  const [provisionalDrafts, setProvisionalDrafts] = useState<Record<string, string>>({});
+  const [submissionErrors, setSubmissionErrors] = useState<Record<string, string>>({});
   const [attachmentsByDraftKey, setAttachmentsByDraftKey] = useState<
     Record<string, LocalComposerAttachment[]>
   >({});
@@ -108,6 +109,7 @@ export function CodingChatPanel({
   const attachmentsRef = useRef(attachmentsByDraftKey);
   const uploadedAttachmentsRef = useRef(new Map<string, CodingAttachmentRef>());
   const uploadFlightsRef = useRef(new Map<string, Promise<CodingAttachmentRef>>());
+  const submissionFlightsRef = useRef(new Set<string>());
 
   const agents = useMemo(() => (
     config?.agents.filter((agent) => agent.enabled && !agent.archivedAt) ?? []
@@ -122,11 +124,16 @@ export function CodingChatPanel({
   ), [conversations, selectedAgent]);
   const selectedConversation = conversations.find((conversation) => (
     conversation.id === selectedConversationId
+      && conversation.agentId === selectedAgent?.id
+      && !conversation.archivedAt
   )) ?? null;
+  const targetConversationId = selectedConversation?.id ?? null;
   const provisionalDraftKey = activeProject && selectedAgent
     ? `new:${activeProject.id}:${selectedAgent.id}`
     : null;
-  const draftKey = selectedConversationId ?? provisionalDraftKey;
+  const draftKey = targetConversationId ?? provisionalDraftKey;
+  const provisionalDraft = provisionalDraftKey ? provisionalDrafts[provisionalDraftKey] ?? '' : '';
+  const submissionError = draftKey ? submissionErrors[draftKey] ?? null : null;
   const localAttachments = useMemo(() => (
     draftKey ? attachmentsByDraftKey[draftKey] ?? [] : []
   ), [attachmentsByDraftKey, draftKey]);
@@ -134,42 +141,47 @@ export function CodingChatPanel({
   attachmentsRef.current = attachmentsByDraftKey;
 
   const selectDraft = useCallback((state: CodingConversationStoreState) => (
-    selectedConversationId
-      ? selectCodingConversationDraft(selectedConversationId)(state)
+    targetConversationId
+      ? selectCodingConversationDraft(targetConversationId)(state)
       : null
-  ), [selectedConversationId]);
+  ), [targetConversationId]);
   const selectedDraft = useCodingConversationStore(selectDraft);
   const selectSnapshot = useCallback((state: CodingConversationStoreState) => (
-    selectedConversationId
-      ? selectCodingConversationSnapshot(selectedConversationId)(state)
+    targetConversationId
+      ? selectCodingConversationSnapshot(targetConversationId)(state)
       : null
-  ), [selectedConversationId]);
+  ), [targetConversationId]);
   const snapshot = useCodingConversationStore(selectSnapshot);
   const entryLoadState = useCodingConversationStore((state) => (
-    selectedConversationId
-      ? state.entriesByConversationId[selectedConversationId]?.loadState ?? 'empty'
+    targetConversationId
+      ? state.entriesByConversationId[targetConversationId]?.loadState ?? 'empty'
       : 'empty'
   ));
   const entryError = useCodingConversationStore((state) => (
-    selectedConversationId
-      ? state.entriesByConversationId[selectedConversationId]?.error ?? null
+    targetConversationId
+      ? state.entriesByConversationId[targetConversationId]?.error ?? null
       : null
   ));
   const blockingRequestCount = useCodingConversationStore((state) => requestCount(
     state,
-    selectedConversationId,
+    targetConversationId,
     BLOCKING_REQUEST_STATUSES,
   ));
   const acceptedRequestCount = useCodingConversationStore((state) => requestCount(
     state,
-    selectedConversationId,
+    targetConversationId,
     ACCEPTED_REQUEST_STATUSES,
   ));
   const uncertainRequestCount = useCodingConversationStore((state) => requestCount(
     state,
-    selectedConversationId,
+    targetConversationId,
     UNCERTAIN_REQUEST_STATUSES,
   ));
+  const submittingRequestCount = useCodingConversationStore((state) => requestCount(
+    state,
+    targetConversationId,
+    SUBMITTING_REQUEST_STATUSES,
+  ));
 
   useEffect(() => {
     void loadWorkspace().catch(() => undefined);
@@ -207,7 +219,11 @@ export function CodingChatPanel({
     void ensureConversation(selectedAgent.id)
       .then((conversation) => {
         primeConversation(createLocalConversationSnapshot(activeProject.id, conversation));
-        void selectConversation(conversation.id).catch(() => undefined);
+        const current = codingWorkspaceStore.getState();
+        if (current.activeProjectId === activeProject.id
+          && current.selectedAgentId === selectedAgent.id) {
+          void selectConversation(conversation.id).catch(() => undefined);
+        }
       })
       .catch(() => undefined);
   }, [
@@ -225,30 +241,38 @@ export function CodingChatPanel({
     const nextDraft = navigationDraft?.trim();
     if (!nextDraft || appliedNavigationDraftRef.current === nextDraft) return;
     appliedNavigationDraftRef.current = nextDraft;
-    if (selectedConversationId) {
-      setConversationDraft(selectedConversationId, nextDraft);
+    if (targetConversationId) {
+      setConversationDraft(targetConversationId, nextDraft);
+    } else if (provisionalDraftKey) {
+      setProvisionalDrafts((current) => ({ ...current, [provisionalDraftKey]: nextDraft }));
     } else {
-      setProvisionalDraft(nextDraft);
+      return;
     }
-  }, [navigationDraft, selectedConversationId, setConversationDraft]);
+  }, [navigationDraft, provisionalDraftKey, setConversationDraft, targetConversationId]);
 
   useEffect(() => {
-    if (!selectedConversationId) return;
+    if (!targetConversationId) return;
     if (provisionalDraft.trim()) {
-      const current = codingConversationStore.getState().draftsByConversationId[selectedConversationId];
-      if (!current?.text) setConversationDraft(selectedConversationId, provisionalDraft);
-      setProvisionalDraft('');
+      const current = codingConversationStore.getState().draftsByConversationId[targetConversationId];
+      if (!current?.text) setConversationDraft(targetConversationId, provisionalDraft);
+      if (provisionalDraftKey) {
+        setProvisionalDrafts((drafts) => {
+          const next = { ...drafts };
+          delete next[provisionalDraftKey];
+          return next;
+        });
+      }
     }
     if (provisionalDraftKey) {
       setAttachmentsByDraftKey((currentAttachments) => {
         const pending = currentAttachments[provisionalDraftKey];
-        if (!pending?.length || currentAttachments[selectedConversationId]?.length) return currentAttachments;
-        const next = { ...currentAttachments, [selectedConversationId]: pending };
+        if (!pending?.length || currentAttachments[targetConversationId]?.length) return currentAttachments;
+        const next = { ...currentAttachments, [targetConversationId]: pending };
         delete next[provisionalDraftKey];
         return next;
       });
     }
-  }, [provisionalDraft, provisionalDraftKey, selectedConversationId, setConversationDraft]);
+  }, [provisionalDraft, provisionalDraftKey, setConversationDraft, targetConversationId]);
 
   const handleSelectConversation = useCallback((conversation: CodingConversationMetadata) => {
     if (!activeProject) return;
@@ -257,19 +281,20 @@ export function CodingChatPanel({
   }, [activeProject, primeConversation, selectConversation]);
 
   const handleCreateConversation = useCallback(async () => {
-    if (!activeProject || !selectedAgent || creatingNewConversation) return;
-    setCreatingNewConversation(true);
-    try {
-      const conversation = await createConversation(selectedAgent.id);
-      primeConversation(createLocalConversationSnapshot(activeProject.id, conversation));
+    if (!activeProject || !selectedAgent || creatingAgentIds[selectedAgent.id]) return;
+    const projectId = activeProject.id;
+    const agentId = selectedAgent.id;
+    const conversation = await createConversation(agentId).catch(() => null);
+    if (!conversation) return;
+    primeConversation(createLocalConversationSnapshot(projectId, conversation));
+    const current = codingWorkspaceStore.getState();
+    if (current.activeProjectId === projectId && current.selectedAgentId === agentId) {
       await selectConversation(conversation.id).catch(() => undefined);
-    } finally {
-      setCreatingNewConversation(false);
     }
   }, [
     activeProject,
     createConversation,
-    creatingNewConversation,
+    creatingAgentIds,
     primeConversation,
     selectConversation,
     selectedAgent,
@@ -278,14 +303,18 @@ export function CodingChatPanel({
   const handleAddFiles = useCallback((files: File[]) => {
     if (!draftKey) return;
     const accepted: LocalComposerAttachment[] = [];
-    for (const file of files) {
+    const remaining = Math.max(0, CODING_ATTACHMENT_MAX_COUNT - localAttachments.length);
+    let validationError = files.length > remaining
+      ? `每条消息最多添加 ${CODING_ATTACHMENT_MAX_COUNT} 张图片。`
+      : null;
+    for (const file of files.slice(0, remaining)) {
       const mime = file.type.trim().toLowerCase();
       if (!CODING_ATTACHMENT_MIMES.has(mime)) {
-        setSubmissionError('仅支持 PNG、JPEG、WebP 或 GIF 图片。');
+        validationError = '仅支持 PNG、JPEG、WebP 或 GIF 图片。';
         continue;
       }
       if (file.size <= 0 || file.size > CODING_ATTACHMENT_MAX_BYTES) {
-        setSubmissionError('图片不能超过 16 MB。');
+        validationError = '图片不能超过 16 MB。';
         continue;
       }
       accepted.push({
@@ -295,13 +324,18 @@ export function CodingChatPanel({
         previewUrl: URL.createObjectURL(file),
       });
     }
+    setSubmissionErrors((current) => {
+      const next = { ...current };
+      if (validationError) next[draftKey] = validationError;
+      else delete next[draftKey];
+      return next;
+    });
     if (accepted.length === 0) return;
-    setSubmissionError(null);
     setAttachmentsByDraftKey((current) => ({
       ...current,
       [draftKey]: [...(current[draftKey] ?? []), ...accepted],
     }));
-  }, [draftKey]);
+  }, [draftKey, localAttachments.length]);
 
   const handleRemoveAttachment = useCallback((id: string) => {
     if (!draftKey) return;
@@ -319,37 +353,54 @@ export function CodingChatPanel({
 
   const prepareAttachments = useCallback(async (
     attachments: LocalComposerAttachment[],
-  ): Promise<CodingDraftAttachment[]> => await Promise.all(attachments.map(async (attachment) => {
-    let uploaded = uploadedAttachmentsRef.current.get(attachment.id);
-    if (!uploaded) {
-      let flight = uploadFlightsRef.current.get(attachment.id);
-      if (!flight) {
-        flight = uploadCodingAttachment(attachment.file);
-        uploadFlightsRef.current.set(attachment.id, flight);
-      }
-      try {
-        uploaded = await flight;
-        uploadedAttachmentsRef.current.set(attachment.id, uploaded);
-      } finally {
-        if (uploadFlightsRef.current.get(attachment.id) === flight) {
-          uploadFlightsRef.current.delete(attachment.id);
+  ): Promise<CodingDraftAttachment[]> => {
+    const prepared = new Array<CodingDraftAttachment>(attachments.length);
+    let nextIndex = 0;
+    const workers = Array.from({
+      length: Math.min(CODING_ATTACHMENT_UPLOAD_CONCURRENCY, attachments.length),
+    }, async () => {
+      while (nextIndex < attachments.length) {
+        const index = nextIndex++;
+        const attachment = attachments[index];
+        let uploaded = uploadedAttachmentsRef.current.get(attachment.id);
+        if (!uploaded) {
+          let flight = uploadFlightsRef.current.get(attachment.id);
+          if (!flight) {
+            flight = uploadCodingAttachment(attachment.file);
+            uploadFlightsRef.current.set(attachment.id, flight);
+          }
+          try {
+            uploaded = await flight;
+            uploadedAttachmentsRef.current.set(attachment.id, uploaded);
+          } finally {
+            if (uploadFlightsRef.current.get(attachment.id) === flight) {
+              uploadFlightsRef.current.delete(attachment.id);
+            }
+          }
         }
+        prepared[index] = {
+          attachmentId: uploaded.attachmentId,
+          mime: uploaded.mime,
+          previewUrl: attachment.previewUrl,
+        };
       }
-    }
-    return {
-      attachmentId: uploaded.attachmentId,
-      mime: uploaded.mime,
-      previewUrl: attachment.previewUrl,
-    };
-  })), []);
+    });
+    await Promise.all(workers);
+    return prepared;
+  }, []);
 
   const handleSubmit = useCallback(() => {
-    if (!selectedConversationId || !draftKey || submitting) return;
+    if (!targetConversationId || !draftKey || submissionFlightsRef.current.has(targetConversationId)) return;
+    const conversationId = targetConversationId;
     const attachments = [...localAttachments];
-    setSubmitting(true);
-    setSubmissionError(null);
+    submissionFlightsRef.current.add(conversationId);
+    setSubmissionErrors((current) => {
+      const next = { ...current };
+      delete next[draftKey];
+      return next;
+    });
     void submitPrompt({
-      conversationId: selectedConversationId,
+      conversationId,
       mode: 'prompt',
       prepareAttachments: attachments.length > 0
         ? () => prepareAttachments(attachments)
@@ -365,17 +416,19 @@ export function CodingChatPanel({
         uploadedAttachmentsRef.current.delete(attachment.id);
       }
     }).catch((error) => {
-      setSubmissionError(error instanceof Error ? error.message : String(error));
+      setSubmissionErrors((current) => ({
+        ...current,
+        [draftKey]: error instanceof Error ? error.message : String(error),
+      }));
     }).finally(() => {
-      setSubmitting(false);
+      submissionFlightsRef.current.delete(conversationId);
     });
   }, [
     draftKey,
     localAttachments,
     prepareAttachments,
-    selectedConversationId,
+    targetConversationId,
     submitPrompt,
-    submitting,
   ]);
 
   const runStatus = snapshot?.run.status ?? 'idle';
@@ -392,10 +445,10 @@ export function CodingChatPanel({
   const editable = Boolean(activeProject && selectedAgent);
   const canSend = Boolean(
     editable
-      && selectedConversationId
+      && targetConversationId
       && (draft.trim() || localAttachments.length > 0)
       && !running
-      && !submitting
+      && submittingRequestCount === 0
       && !preparationError
       && blockingRequestCount === 0
       && uncertainRequestCount === 0,
@@ -439,7 +492,10 @@ export function CodingChatPanel({
                   'flex min-h-10 w-full items-center gap-2 rounded-xl px-2.5 text-left text-sm transition-[background-color,scale] duration-150 ease-out active:scale-[0.96]',
                   selectedAgent?.id === agent.id ? 'bg-background font-medium shadow-soft' : 'hover:bg-background/70',
                 )}
-                onClick={() => selectAgent(agent.id)}
+                onClick={() => {
+                  clearConversationSelection();
+                  selectAgent(agent.id);
+                }}
               >
                 <span className="flex h-7 w-7 shrink-0 items-center justify-center rounded-lg bg-foreground text-xs font-semibold text-background">
                   {agent.name.trim().slice(0, 1) || 'A'}
@@ -456,10 +512,10 @@ export function CodingChatPanel({
               size="icon"
               className="h-10 w-10 rounded-xl transition-transform duration-150 ease-out active:scale-[0.96]"
               aria-label="新建对话"
-              disabled={!selectedAgent || creatingNewConversation}
+              disabled={!selectedAgent || Boolean(selectedAgent && creatingAgentIds[selectedAgent.id])}
               onClick={() => void handleCreateConversation()}
             >
-              {creatingNewConversation
+              {selectedAgent && creatingAgentIds[selectedAgent.id]
                 ? <LoaderCircle className="h-4 w-4 animate-spin" aria-hidden="true" />
                 : <MessageSquarePlus className="h-4 w-4" aria-hidden="true" />}
             </Button>
@@ -471,7 +527,7 @@ export function CodingChatPanel({
                 type="button"
                 className={cn(
                   'min-h-10 w-full truncate rounded-xl px-3 text-left text-sm transition-[background-color,scale] duration-150 ease-out active:scale-[0.96]',
-                  selectedConversationId === conversation.id
+                  targetConversationId === conversation.id
                     ? 'bg-background font-medium shadow-soft'
                     : 'text-muted-foreground hover:bg-background/70 hover:text-foreground',
                 )}
@@ -530,11 +586,11 @@ export function CodingChatPanel({
           </div>
         )}
 
-        {selectedConversationId
+        {targetConversationId
           ? (
             <CodingConversationTimeline
-              key={selectedConversationId}
-              conversationId={selectedConversationId}
+              key={targetConversationId}
+              conversationId={targetConversationId}
             />
           )
           : (
@@ -552,17 +608,25 @@ export function CodingChatPanel({
           recoverableError={!submissionError && Boolean(preparationError)}
           acceptedCount={acceptedRequestCount}
           attachments={localAttachments.map(({ id, name, previewUrl }) => ({ id, name, previewUrl }))}
-          submitting={submitting}
+          submitting={submittingRequestCount > 0}
           placeholder={selectedAgent ? '给当前对话发送消息' : '请选择一个伙伴后再发送'}
           onChange={(value) => {
-            setSubmissionError(null);
-            if (selectedConversationId) setConversationDraft(selectedConversationId, value);
-            else setProvisionalDraft(value);
+            if (draftKey) {
+              setSubmissionErrors((current) => {
+                const next = { ...current };
+                delete next[draftKey];
+                return next;
+              });
+            }
+            if (targetConversationId) setConversationDraft(targetConversationId, value);
+            else if (provisionalDraftKey) {
+              setProvisionalDrafts((current) => ({ ...current, [provisionalDraftKey]: value }));
+            }
           }}
           onSubmit={handleSubmit}
           onRecover={() => {
-            if (selectedConversationId) {
-              void recoverConversation(selectedConversationId).catch(() => undefined);
+            if (targetConversationId) {
+              void recoverConversation(targetConversationId).catch(() => undefined);
             }
           }}
           onAddFiles={handleAddFiles}
diff --git a/src/stores/coding-conversations.ts b/src/stores/coding-conversations.ts
index e3591a2..6b45c44 100644
--- a/src/stores/coding-conversations.ts
+++ b/src/stores/coding-conversations.ts
@@ -338,6 +338,7 @@ export function createCodingConversationStore(
   const deps = { ...defaultDependencies(), ...dependencies };
   const snapshotLoads = new Map<string, Promise<ConversationSnapshot>>();
   const recoveryBatches = new Map<string, CodingConversationPatchBatchEvent[]>();
+  const recoveryRefreshKeys = new Map<string, string>();
   let eventSource: EventSource | null = null;
   let connectFlight: Promise<void> | null = null;
   let connectionGeneration = 0;
@@ -375,11 +376,20 @@ export function createCodingConversationStore(
     const items = [...itemsBySeq.values()].sort((left, right) => left.seq - right.seq);
     if (items.length === 0) {
       recoveryBatches.delete(conversationId);
+      recoveryRefreshKeys.delete(conversationId);
       return;
     }
     const continuous = items[0].seq === snapshot.cursor.seq + 1
       && items.every((item, index) => index === 0 || item.seq === items[index - 1].seq + 1);
     if (!continuous) {
+      const lastSeq = items.at(-1)?.seq ?? items[0].seq;
+      const refreshKey = [
+        snapshot.cursor.workerGeneration,
+        snapshot.cursor.seq,
+        items[0].seq,
+        lastSeq,
+      ].join(':');
+      const willRefresh = recoveryRefreshKeys.get(conversationId) !== refreshKey;
       store.setState((state) => {
         const current = state.entriesByConversationId[conversationId] ?? emptyEntry();
         return {
@@ -387,15 +397,24 @@ export function createCodingConversationStore(
             ...state.entriesByConversationId,
             [conversationId]: {
               ...current,
-              loadState: 'recovering',
+              loadState: willRefresh ? 'recovering' : 'error',
               error: 'Conversation patch batch is not continuous',
             },
           },
         };
       });
+      if (willRefresh) {
+        recoveryRefreshKeys.set(conversationId, refreshKey);
+        queueMicrotask(() => {
+          if (!snapshotLoads.has(conversationId)) {
+            void store.getState().loadSnapshot(conversationId, true).catch(() => undefined);
+          }
+        });
+      }
       return;
     }
     recoveryBatches.delete(conversationId);
+    recoveryRefreshKeys.delete(conversationId);
     store.getState().applyPatchBatchEvent({
       type: 'patch-batch',
       conversationId,
@@ -521,6 +540,7 @@ export function createCodingConversationStore(
     },
 
     async recoverConversation(conversationId) {
+      recoveryRefreshKeys.delete(conversationId);
       set((state) => {
         const entry = state.entriesByConversationId[conversationId] ?? emptyEntry();
         return {
diff --git a/tests/e2e/pi-coding-first-chat.spec.ts b/tests/e2e/pi-coding-first-chat.spec.ts
index 2dafb28..4d5aa5f 100644
--- a/tests/e2e/pi-coding-first-chat.spec.ts
+++ b/tests/e2e/pi-coding-first-chat.spec.ts
@@ -5,9 +5,16 @@ type CapturedRequest = {
   path: string;
   method: string;
   body?: Record<string, unknown>;
+  byteLength?: number;
+  contentType?: string;
   at: number;
 };
 
+type HostConnection = {
+  baseUrl: string;
+  token: string;
+};
+
 async function disableCodingEventSource(page: Page): Promise<void> {
   await page.addInitScript(() => {
     class LocalEventSource extends EventTarget {
@@ -43,8 +50,11 @@ async function disableCodingEventSource(page: Page): Promise<void> {
   });
 }
 
-async function installCodingFirstChatHost(electronApp: ElectronApplication): Promise<void> {
-  await electronApp.evaluate(async () => {
+async function installCodingFirstChatHost(
+  electronApp: ElectronApplication,
+  hostConnection: HostConnection,
+): Promise<void> {
+  await electronApp.evaluate(async (_, connection) => {
     const { ipcMain } = process.mainModule!.require('electron') as typeof import('electron');
     type MainState = {
       captured: CapturedRequest[];
@@ -148,14 +158,71 @@ async function installCodingFirstChatHost(electronApp: ElectronApplication): Pro
     ipcMain.removeHandler('hostapi:fetch');
     ipcMain.handle('hostapi:fetch', async (
       _event,
-      request: { path?: string; method?: string; body?: unknown },
+      request: {
+        path?: string;
+        method?: string;
+        headers?: Record<string, string>;
+        body?: unknown;
+      },
     ) => {
       const path = request.path ?? '';
       const method = request.method ?? 'GET';
       const body = typeof request.body === 'string' && request.body
         ? JSON.parse(request.body) as Record<string, unknown>
         : undefined;
-      state.captured.push({ path, method, ...(body ? { body } : {}), at: Date.now() });
+      const binaryBody = request.body instanceof ArrayBuffer
+        ? new Uint8Array(request.body)
+        : ArrayBuffer.isView(request.body)
+          ? new Uint8Array(
+              request.body.buffer,
+              request.body.byteOffset,
+              request.body.byteLength,
+            )
+          : undefined;
+      state.captured.push({
+        path,
+        method,
+        ...(body ? { body } : {}),
+        ...(binaryBody ? { byteLength: binaryBody.byteLength } : {}),
+        ...(request.headers?.['Content-Type']
+          ? { contentType: request.headers['Content-Type'] }
+          : {}),
+        at: Date.now(),
+      });
+
+      if (path === '/api/coding/attachments'
+        || /^\/api\/coding\/attachments\/[^/]+\/content$/.test(path)) {
+        const response = await fetch(`${connection.baseUrl}${path}`, {
+          method,
+          headers: {
+            Authorization: `Bearer ${connection.token}`,
+            ...(request.headers ?? {}),
+          },
+          ...(binaryBody ? { body: binaryBody } : {}),
+        });
+        const responseContentType = response.headers.get('content-type') ?? '';
+        if (responseContentType.includes('application/json')) {
+          return {
+            ok: true,
+            data: {
+              status: response.status,
+              ok: response.ok,
+              json: await response.json(),
+              transport: 'loopback',
+            },
+          };
+        }
+        return {
+          ok: true,
+          data: {
+            status: response.status,
+            ok: response.ok,
+            bytes: new Uint8Array(await response.arrayBuffer()),
+            contentType: responseContentType.split(';', 1)[0]?.trim(),
+            transport: 'loopback',
+          },
+        };
+      }
 
       if (path === '/api/coding/projects') {
         return respond({ projects: [project], activeProjectId: project.id });
@@ -205,7 +272,7 @@ async function installCodingFirstChatHost(electronApp: ElectronApplication): Pro
       }
       return respond({ success: false, error: `Unhandled E2E route: ${method} ${path}` }, 404);
     });
-  });
+  }, hostConnection);
 }
 
 async function readState(electronApp: ElectronApplication): Promise<{
@@ -239,8 +306,12 @@ test('first PI Conversation is editable under 500 ms and submits before runtime
   launchElectronApp,
 }) => {
   const electronApp = await launchElectronApp({ skipSetup: true });
-  await installCodingFirstChatHost(electronApp);
   let page = await getStableWindow(electronApp);
+  const hostConnection = await page.evaluate(async () => ({
+    token: await window.electron.ipcRenderer.invoke('hostapi:token') as string,
+    baseUrl: await window.electron.ipcRenderer.invoke('hostapi:base-url') as string,
+  }));
+  await installCodingFirstChatHost(electronApp, hostConnection);
   await disableCodingEventSource(page);
 
   try {
@@ -260,6 +331,15 @@ test('first PI Conversation is editable under 500 ms and submits before runtime
     ));
     expect(editableMs).toBeLessThan(500);
 
+    const pixelPng = Buffer.from(
+      'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mNk+A8AAQUBAScY42YAAAAASUVORK5CYII=',
+      'base64',
+    );
+    await page.getByTestId('coding-file-attachment-input').setInputFiles({
+      name: 'pixel.png',
+      mimeType: 'image/png',
+      buffer: pixelPng,
+    });
     await composer.fill('Build the first PI scene');
     await expect(page.getByRole('button', { name: '发送' })).toBeEnabled();
     await page.getByTestId('coding-message-composer').evaluate(
@@ -279,7 +359,28 @@ test('first PI Conversation is editable under 500 ms and submits before runtime
     await expect(
       page.getByTestId('coding-conversation-timeline').getByText('Build the first PI scene'),
     ).toBeVisible();
+    await expect(page.getByRole('img', { name: '对话图片附件' })).toBeVisible();
     await expect(page.getByText('1 条消息已被本地 Agent 接收。')).toBeVisible();
+    const state = await readState(electronApp);
+    const uploads = state.captured.filter((request) => (
+      request.path === '/api/coding/attachments' && request.method === 'POST'
+    ));
+    expect(uploads).toHaveLength(1);
+    expect(uploads[0]).toMatchObject({
+      byteLength: pixelPng.byteLength,
+      contentType: 'image/png',
+    });
+    expect(state.captured.some((request) => (
+      /^\/api\/coding\/attachments\/[^/]+\/content$/.test(request.path)
+      && request.method === 'GET'
+    ))).toBe(true);
+    const prompt = state.captured.find((request) => (
+      request.path === '/api/coding/conversations/conversation-pi-first-chat/prompt'
+    ));
+    expect(prompt?.body?.attachments).toEqual([
+      { attachmentId: expect.any(String) },
+    ]);
+    expect(JSON.stringify(state.captured)).not.toContain(pixelPng.toString('base64'));
   } finally {
     await releaseSnapshot(electronApp);
   }
diff --git a/tests/unit/coding-attachments-routes.test.ts b/tests/unit/coding-attachments-routes.test.ts
index 13eaf5f..02408db 100644
--- a/tests/unit/coding-attachments-routes.test.ts
+++ b/tests/unit/coding-attachments-routes.test.ts
@@ -1,9 +1,11 @@
 import { createServer, request as httpRequest } from 'node:http';
+import { once } from 'node:events';
 import { mkdtemp, rm } from 'node:fs/promises';
 import { tmpdir } from 'node:os';
 import path from 'node:path';
 import { afterEach, describe, expect, it } from 'vitest';
 import { handleCodingAttachmentRoutes } from '../../electron/api/routes/coding-attachments';
+import { getHostApiToken, startHostApiServer } from '../../electron/api/server';
 import { CodingAttachmentStore } from '../../electron/coding-projects/attachment-store';
 import type { HostApiContext } from '../../electron/api/context';
 
@@ -36,6 +38,29 @@ async function startAttachmentServer(maxBytes = 16 * 1024 * 1024) {
   return {
     baseUrl: `http://127.0.0.1:${address.port}`,
     close: async () => await new Promise<void>((resolve, reject) => {
+      server.closeAllConnections();
+      server.close((error) => error ? reject(error) : resolve());
+    }),
+  };
+}
+
+async function startAuthenticatedHostServer() {
+  const root = await mkdtemp(path.join(tmpdir(), 'makelore-coding-host-attachments-'));
+  roots.push(root);
+  const attachments = new CodingAttachmentStore(root, { createId: () => 'host-attachment-1' });
+  const context = {
+    opencodeManager: { getStatus: () => ({ url: null }) },
+    codingProducts: { attachments },
+  } as unknown as HostApiContext;
+  const server = startHostApiServer(context, 0);
+  await once(server, 'listening');
+  const address = server.address();
+  if (!address || typeof address === 'string') throw new Error('Host API test server failed');
+  return {
+    baseUrl: `http://127.0.0.1:${address.port}`,
+    token: getHostApiToken(),
+    close: async () => await new Promise<void>((resolve, reject) => {
+      server.closeAllConnections();
       server.close((error) => error ? reject(error) : resolve());
     }),
   };
@@ -66,10 +91,43 @@ async function postDeclaredLength(
 }
 
 describe('coding attachment routes', () => {
+  it('accepts authenticated binary uploads through the production Host API gate', async () => {
+    const server = await startAuthenticatedHostServer();
+    try {
+      const bytes = new Uint8Array([137, 80, 78, 71, 13, 10, 26, 10, 1]);
+      const upload = await fetch(`${server.baseUrl}/api/coding/attachments`, {
+        method: 'POST',
+        headers: {
+          Authorization: `Bearer ${server.token}`,
+          'Content-Type': 'image/png',
+        },
+        body: bytes,
+      });
+      expect(upload.status).toBe(201);
+      await expect(upload.json()).resolves.toEqual({
+        attachmentId: 'host-attachment-1',
+        mime: 'image/png',
+        byteLength: bytes.byteLength,
+      });
+
+      const unrelatedMutation = await fetch(`${server.baseUrl}/api/coding/projects`, {
+        method: 'POST',
+        headers: {
+          Authorization: `Bearer ${server.token}`,
+          'Content-Type': 'image/png',
+        },
+        body: bytes,
+      });
+      expect(unrelatedMutation.status).toBe(415);
+    } finally {
+      await server.close();
+    }
+  });
+
   it('round-trips bounded image bytes through attachment ids', async () => {
     const server = await startAttachmentServer();
     try {
-      const bytes = new Uint8Array([137, 80, 78, 71, 1, 2, 3]);
+      const bytes = new Uint8Array([137, 80, 78, 71, 13, 10, 26, 10, 1, 2, 3]);
       const upload = await fetch(`${server.baseUrl}/api/coding/attachments`, {
         method: 'POST',
         headers: { 'Content-Type': 'image/png' },
@@ -119,6 +177,42 @@ describe('coding attachment routes', () => {
     }
   });
 
+  it('rejects bytes that do not match the declared image MIME', async () => {
+    const server = await startAttachmentServer();
+    try {
+      const upload = await fetch(`${server.baseUrl}/api/coding/attachments`, {
+        method: 'POST',
+        headers: { 'Content-Type': 'image/png' },
+        body: 'not actually a png',
+      });
+      expect(upload.status).toBe(400);
+      await expect(upload.json()).resolves.toMatchObject({
+        code: 'CODING_ATTACHMENT_INVALID',
+      });
+    } finally {
+      await server.close();
+    }
+  });
+
+  it.each([
+    ['image/jpeg', new Uint8Array([0xff, 0xd8, 0xff, 0x01])],
+    ['image/gif', new TextEncoder().encode('GIF89a!')],
+    ['image/webp', new TextEncoder().encode('RIFF\x04\x00\x00\x00WEBP')],
+  ])('accepts the minimal %s image signature', async (mime, bytes) => {
+    const server = await startAttachmentServer();
+    try {
+      const upload = await fetch(`${server.baseUrl}/api/coding/attachments`, {
+        method: 'POST',
+        headers: { 'Content-Type': mime },
+        body: bytes,
+      });
+      expect(upload.status).toBe(201);
+      await expect(upload.json()).resolves.toMatchObject({ mime });
+    } finally {
+      await server.close();
+    }
+  });
+
   it('rejects a declared body larger than the route limit', async () => {
     const server = await startAttachmentServer();
     try {
@@ -134,4 +228,28 @@ describe('coding attachment routes', () => {
       await server.close();
     }
   });
+
+  it('maps empty bodies and invalid opaque ids to stable client errors', async () => {
+    const server = await startAttachmentServer();
+    try {
+      const empty = await fetch(`${server.baseUrl}/api/coding/attachments`, {
+        method: 'POST',
+        headers: { 'Content-Type': 'image/png' },
+      });
+      expect(empty.status).toBe(400);
+      await expect(empty.json()).resolves.toMatchObject({
+        code: 'CODING_ATTACHMENT_INVALID',
+      });
+
+      for (const id of ['bad%2Fid', '%ZZ']) {
+        const invalid = await fetch(`${server.baseUrl}/api/coding/attachments/${id}/content`);
+        expect(invalid.status).toBe(400);
+        await expect(invalid.json()).resolves.toMatchObject({
+          code: 'CODING_ATTACHMENT_INVALID',
+        });
+      }
+    } finally {
+      await server.close();
+    }
+  });
 });
diff --git a/tests/unit/coding-chat-panel.test.tsx b/tests/unit/coding-chat-panel.test.tsx
index 2271054..59619c0 100644
--- a/tests/unit/coding-chat-panel.test.tsx
+++ b/tests/unit/coding-chat-panel.test.tsx
@@ -1,7 +1,7 @@
 import { act, fireEvent, render, screen, waitFor } from '@testing-library/react';
 import { readFile } from 'node:fs/promises';
 import { fileURLToPath } from 'node:url';
-import { afterEach, describe, expect, it, vi } from 'vitest';
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
 import type { ConversationSnapshot } from '@/types/coding-conversation';
 import type {
   CodingConversationMetadata,
@@ -58,7 +58,7 @@ const agent: CodingProjectAgent = {
   createdAt: '2026-08-23T00:00:00.000Z',
   updatedAt: '2026-08-23T00:00:00.000Z',
   model: null,
-  modelResolution: 'default',
+  modelResolution: 'required',
 };
 const config: CodingProjectConfig = {
   schemaVersion: 2,
@@ -79,8 +79,24 @@ const conversation: CodingConversationMetadata = {
   createdAt: '2026-08-23T00:00:00.000Z',
   updatedAt: '2026-08-23T00:00:00.000Z',
   model: null,
-  modelResolution: 'default',
+  modelResolution: 'required',
 };
+const reviewer: CodingProjectAgent = {
+  ...agent,
+  id: 'agent-2',
+  name: 'Reviewer',
+  pinned: false,
+};
+const reviewerConversation: CodingConversationMetadata = {
+  ...conversation,
+  id: 'conversation-2',
+  agentId: reviewer.id,
+  title: 'Reviewer conversation',
+};
+
+function configForAgents(agents: CodingProjectAgent[]): CodingProjectConfig {
+  return { ...config, agents };
+}
 
 const projectApi = vi.hoisted(() => ({
   list: vi.fn(),
@@ -94,6 +110,7 @@ const conversationApi = vi.hoisted(() => ({
   submit: vi.fn(),
   recover: vi.fn(),
 }));
+const attachmentApi = vi.hoisted(() => ({ upload: vi.fn() }));
 
 vi.mock('@/lib/coding-projects', () => ({
   listCodingProjects: projectApi.list,
@@ -109,8 +126,28 @@ vi.mock('@/lib/coding-conversations', () => ({
   recoverCodingConversation: conversationApi.recover,
 }));
 
+vi.mock('@/lib/coding-attachments', async (importOriginal) => ({
+  ...await importOriginal<typeof import('@/lib/coding-attachments')>(),
+  uploadCodingAttachment: attachmentApi.upload,
+}));
+
 describe('CodingChatPanel first Conversation', () => {
-  afterEach(() => vi.restoreAllMocks());
+  beforeEach(() => {
+    Object.defineProperty(URL, 'createObjectURL', {
+      configurable: true,
+      value: vi.fn((file: File) => `blob:${file.name}`),
+    });
+    Object.defineProperty(URL, 'revokeObjectURL', {
+      configurable: true,
+      value: vi.fn(),
+    });
+  });
+
+  afterEach(() => {
+    vi.restoreAllMocks();
+    vi.clearAllMocks();
+    vi.resetModules();
+  });
 
   it('makes the first-Conversation textarea editable while runtime metadata is held', async () => {
     projectApi.list.mockResolvedValue({ projects: [project], activeProjectId: project.id });
@@ -166,6 +203,168 @@ describe('CodingChatPanel first Conversation', () => {
     }
   });
 
+  it('does not let a slow first-Conversation completion steal selection after an Agent switch', async () => {
+    const slowCreate = deferred<CodingConversationMetadata>();
+    projectApi.list.mockResolvedValue({ projects: [project], activeProjectId: project.id });
+    projectApi.config.mockResolvedValue({ project, config: configForAgents([agent, reviewer]) });
+    projectApi.conversations.mockResolvedValue([reviewerConversation]);
+    projectApi.create.mockReturnValue(slowCreate.promise);
+    conversationApi.events.mockResolvedValue(new FakeEventSource() as unknown as EventSource);
+    conversationApi.submit.mockRejectedValue(new Error('Provider is intentionally not used'));
+    conversationApi.recover.mockResolvedValue(undefined);
+    const { CodingChatPanel } = await import('@/pages/Chat/CodingChatPanel');
+    const { createLocalConversationSnapshot } = await import('@/pages/Chat/coding-chat-snapshot');
+    const { codingConversationStore } = await import('@/stores/coding-conversations');
+    conversationApi.snapshot.mockImplementation(async (conversationId: string) => (
+      createLocalConversationSnapshot(
+        project.id,
+        conversationId === reviewerConversation.id ? reviewerConversation : conversation,
+      )
+    ));
+    render(<CodingChatPanel />);
+
+    await screen.findByRole('textbox');
+    await waitFor(() => expect(projectApi.create).toHaveBeenCalledWith({
+      projectId: project.id,
+      agentId: agent.id,
+      title: '新对话',
+    }));
+    fireEvent.click(screen.getByRole('button', { name: /Reviewer/ }));
+    await waitFor(() => expect(codingConversationStore.getState().selectedConversationId)
+      .toBe(reviewerConversation.id));
+
+    await act(async () => {
+      slowCreate.resolve(conversation);
+      await slowCreate.promise;
+    });
+    expect(codingConversationStore.getState().selectedConversationId).toBe(reviewerConversation.id);
+  });
+
+  it('keeps submission state and rejection scoped to the originating Conversation', async () => {
+    const pendingSubmit = deferred<never>();
+    projectApi.list.mockResolvedValue({ projects: [project], activeProjectId: project.id });
+    projectApi.config.mockResolvedValue({ project, config: configForAgents([agent, reviewer]) });
+    projectApi.conversations.mockResolvedValue([conversation, reviewerConversation]);
+    conversationApi.events.mockResolvedValue(new FakeEventSource() as unknown as EventSource);
+    conversationApi.submit.mockReturnValueOnce(pendingSubmit.promise);
+    conversationApi.recover.mockResolvedValue(undefined);
+    const { CodingChatPanel } = await import('@/pages/Chat/CodingChatPanel');
+    const { createLocalConversationSnapshot } = await import('@/pages/Chat/coding-chat-snapshot');
+    const { codingConversationStore } = await import('@/stores/coding-conversations');
+    conversationApi.snapshot.mockImplementation(async (conversationId: string) => (
+      createLocalConversationSnapshot(
+        project.id,
+        conversationId === reviewerConversation.id ? reviewerConversation : conversation,
+      )
+    ));
+    render(<CodingChatPanel />);
+
+    const textbox = await screen.findByRole('textbox');
+    await waitFor(() => expect(codingConversationStore.getState().selectedConversationId)
+      .toBe(conversation.id));
+    fireEvent.change(textbox, { target: { value: 'A prompt' } });
+    await waitFor(() => expect(
+      codingConversationStore.getState().draftsByConversationId[conversation.id]?.text,
+    ).toBe('A prompt'));
+    expect(codingConversationStore.getState().entriesByConversationId[conversation.id])
+      .toMatchObject({ loadState: 'live', error: null });
+    await waitFor(() => expect(screen.getByRole('button', { name: '发送' })).toBeEnabled());
+    fireEvent.click(screen.getByRole('button', { name: '发送' }));
+    await waitFor(() => expect(conversationApi.submit).toHaveBeenCalledOnce());
+
+    fireEvent.click(screen.getByRole('button', { name: /Reviewer/ }));
+    await waitFor(() => expect(screen.getByRole('textbox')).toHaveValue(''));
+    fireEvent.change(screen.getByRole('textbox'), { target: { value: 'B prompt' } });
+    await waitFor(() => expect(screen.getByRole('button', { name: '发送' })).toBeEnabled());
+
+    await act(async () => {
+      pendingSubmit.reject(new Error('A submission failed'));
+      await pendingSubmit.promise.catch(() => undefined);
+    });
+    expect(screen.queryByText('A submission failed')).not.toBeInTheDocument();
+    expect(screen.getByRole('textbox')).toHaveValue('B prompt');
+    expect(screen.getByRole('button', { name: '发送' })).toBeEnabled();
+  });
+
+  it('caps one message at 16 images and uploads at most four concurrently', async () => {
+    projectApi.list.mockResolvedValue({ projects: [project], activeProjectId: project.id });
+    projectApi.config.mockResolvedValue({ project, config });
+    projectApi.conversations.mockResolvedValue([conversation]);
+    conversationApi.events.mockResolvedValue(new FakeEventSource() as unknown as EventSource);
+    conversationApi.recover.mockResolvedValue(undefined);
+    conversationApi.submit.mockImplementation(async (input: {
+      conversationId: string;
+      clientRequestId: string;
+      mode: 'prompt';
+    }) => ({
+      accepted: true,
+      conversationId: input.conversationId,
+      clientRequestId: input.clientRequestId,
+      runId: 'run-1',
+      mode: input.mode,
+    }));
+    const uploadFlights: Array<ReturnType<typeof deferred<{
+      attachmentId: string;
+      mime: string;
+      byteLength: number;
+    }>>> = [];
+    let activeUploads = 0;
+    let maxActiveUploads = 0;
+    attachmentApi.upload.mockImplementation((file: File) => {
+      const flight = deferred<{ attachmentId: string; mime: string; byteLength: number }>();
+      uploadFlights.push(flight);
+      activeUploads += 1;
+      maxActiveUploads = Math.max(maxActiveUploads, activeUploads);
+      return flight.promise.finally(() => {
+        activeUploads -= 1;
+      }).then(() => ({
+        attachmentId: `attachment-${file.name}`,
+        mime: file.type,
+        byteLength: file.size,
+      }));
+    });
+    const { CodingChatPanel } = await import('@/pages/Chat/CodingChatPanel');
+    const { createLocalConversationSnapshot } = await import('@/pages/Chat/coding-chat-snapshot');
+    const { codingConversationStore } = await import('@/stores/coding-conversations');
+    conversationApi.snapshot.mockResolvedValue(createLocalConversationSnapshot(project.id, conversation));
+    render(<CodingChatPanel />);
+    await screen.findByRole('textbox');
+    await waitFor(() => expect(codingConversationStore.getState().selectedConversationId)
+      .toBe(conversation.id));
+
+    const files = Array.from({ length: 17 }, (_, index) => new File(
+      [new Uint8Array([137, 80, 78, 71, 13, 10, 26, 10, index])],
+      `image-${index}.png`,
+      { type: 'image/png' },
+    ));
+    fireEvent.change(screen.getByTestId('coding-file-attachment-input'), {
+      target: { files },
+    });
+    expect(await screen.findByText('每条消息最多添加 16 张图片。')).toBeInTheDocument();
+    expect(screen.getAllByRole('img')).toHaveLength(16);
+    expect(codingConversationStore.getState().entriesByConversationId[conversation.id])
+      .toMatchObject({ loadState: 'live', error: null });
+    await waitFor(() => expect(screen.getByRole('button', { name: '发送' })).toBeEnabled());
+    fireEvent.click(screen.getByRole('button', { name: '发送' }));
+    await waitFor(() => expect(attachmentApi.upload).toHaveBeenCalledTimes(4));
+
+    let resolved = 0;
+    while (resolved < 16) {
+      const available = uploadFlights.slice(resolved);
+      for (const flight of available) flight.resolve({
+        attachmentId: `resolved-${resolved++}`,
+        mime: 'image/png',
+        byteLength: 9,
+      });
+      if (resolved < 16) {
+        await waitFor(() => expect(uploadFlights.length).toBeGreaterThan(resolved));
+      }
+    }
+    await waitFor(() => expect(conversationApi.submit).toHaveBeenCalledOnce());
+    expect(attachmentApi.upload).toHaveBeenCalledTimes(16);
+    expect(maxActiveUploads).toBeLessThanOrEqual(4);
+  });
+
   it('shows the 202 acceptance and preserves Enter versus Shift+Enter behavior', async () => {
     const { CodingComposer } = await import('@/pages/Chat/CodingComposer');
     const onSubmit = vi.fn();
diff --git a/tests/unit/coding-chat-pressure.test.tsx b/tests/unit/coding-chat-pressure.test.tsx
new file mode 100644
index 0000000..348b5b3
--- /dev/null
+++ b/tests/unit/coding-chat-pressure.test.tsx
@@ -0,0 +1,235 @@
+import { act, render } from '@testing-library/react';
+import { mkdtemp, rm } from 'node:fs/promises';
+import { createServer } from 'node:http';
+import { tmpdir } from 'node:os';
+import path from 'node:path';
+import { Profiler } from 'react';
+import { afterEach, describe, expect, it, vi } from 'vitest';
+import type { HostApiContext } from '../../electron/api/context';
+import { handleCodingConversationRoutes } from '../../electron/api/routes/coding-conversations';
+import { CodingProjectService } from '../../electron/coding-projects/project-service';
+import { createCodingProjectAgent } from '../../electron/coding-projects/project-config';
+import {
+  createCodingProjectStore,
+  createLocalCodingProject,
+  createMemoryCodingProjectStorage,
+} from '../../electron/coding-projects/project-store';
+import { CodingConversationService } from '../../electron/coding-runtime/conversation-service';
+import { InMemoryConversationRuntime } from '../../electron/coding-runtime/in-memory-conversation-runtime';
+import type {
+  CodingConversationPatchBatchEvent,
+  CodingConversationSnapshotEvent,
+  ConversationPatch,
+  ConversationPatchEnvelope,
+} from '../../electron/coding-runtime/contracts';
+import { CodingConversationTimeline } from '../../src/pages/Chat/CodingConversationTimeline';
+import { codingConversationStore } from '../../src/stores/coding-conversations';
+
+const roots: string[] = [];
+
+afterEach(async () => {
+  await Promise.all(roots.splice(0).map((root) => rm(root, { recursive: true, force: true })));
+});
+
+function percentile95(values: number[]): number {
+  const ordered = [...values].sort((left, right) => left - right);
+  return ordered[Math.ceil(ordered.length * 0.95) - 1] ?? Number.POSITIVE_INFINITY;
+}
+
+function pressurePatch(seq: number): ConversationPatch {
+  if (seq === 1) {
+    return {
+      op: 'message.upsert',
+      node: {
+        kind: 'message',
+        id: 'assistant-pressure',
+        role: 'assistant',
+        status: 'streaming',
+        blocks: [
+          { kind: 'text', id: 'answer-pressure', text: 'Mixed answer', status: 'complete' },
+          { kind: 'thinking', id: 'thinking-pressure', text: '', status: 'streaming' },
+        ],
+      },
+    };
+  }
+  if (seq === 2) {
+    return {
+      op: 'tool.upsert',
+      node: {
+        kind: 'tool',
+        id: 'tool-pressure',
+        toolCallId: 'call-pressure',
+        toolName: 'read',
+        title: 'Pressure fixture tool output',
+        inputText: 'fixture.txt',
+        status: 'complete',
+        output: [{
+          kind: 'text',
+          id: 'tool-pressure-output',
+          text: 'T'.repeat(4 * 1024),
+          status: 'complete',
+        }],
+      },
+    };
+  }
+  return {
+    op: 'message.block-delta',
+    messageId: 'assistant-pressure',
+    blockId: 'thinking-pressure',
+    delta: `${seq}:`.padEnd(1_100, 'x'),
+  };
+}
+
+describe('REN-008 coding timeline pressure', () => {
+  it('batches 100 KB of mixed output and keeps Main-to-React p95 within 50 ms', async () => {
+    const root = await mkdtemp(path.join(tmpdir(), 'makelore-pi-pressure-'));
+    roots.push(root);
+    const projectStore = createCodingProjectStore(createMemoryCodingProjectStorage(), {
+      createId: () => 'project-pressure',
+      now: () => '2026-08-24T00:00:00.000Z',
+    });
+    await createLocalCodingProject({
+      projectPath: root,
+      now: '2026-08-24T00:00:00.000Z',
+    }, projectStore);
+    await createCodingProjectAgent(root, {
+      id: 'builder',
+      avatarId: 'avatar-01',
+      roleName: '实现者',
+      name: 'Builder',
+      model: { accountId: 'account-a', modelId: 'model-a', thinkingLevel: 'medium' },
+      modelResolution: 'resolved',
+      responsibility: {
+        mission: 'Implement', owns: [], boundaries: [], collaborators: [], principles: [],
+      },
+    }, { now: '2026-08-24T00:00:00.000Z' });
+    const runtime = new InMemoryConversationRuntime();
+    const projects = new CodingProjectService(projectStore);
+    const conversations = new CodingConversationService(projects, runtime, {
+      deliveryBatchWindowMs: 24,
+    });
+    const conversation = await conversations.createConversation({
+      agentId: 'builder',
+      title: 'Pressure',
+    });
+    let publish: ((event: ConversationPatchEnvelope) => void) | undefined;
+    vi.spyOn(runtime, 'subscribe').mockImplementation((listener) => {
+      publish = listener;
+      return () => undefined;
+    });
+    const context = {
+      codingProducts: { projects, conversations, runtime },
+    } as unknown as HostApiContext;
+    const server = createServer((request, response) => {
+      const url = new URL(request.url ?? '/', 'http://127.0.0.1');
+      void handleCodingConversationRoutes(request, response, url, context);
+    });
+    await new Promise<void>((resolve, reject) => {
+      server.once('error', reject);
+      server.listen(0, '127.0.0.1', resolve);
+    });
+    const address = server.address();
+    if (!address || typeof address === 'string') throw new Error('Pressure server did not bind');
+    const controller = new AbortController();
+    const response = await fetch(
+      `http://127.0.0.1:${address.port}/api/coding/events?conversationId=${conversation.id}`,
+      { signal: controller.signal },
+    );
+    const reader = response.body?.getReader();
+    if (!reader) throw new Error('Pressure SSE response has no body');
+    const decoder = new TextDecoder();
+    const encoder = new TextEncoder();
+    let buffered = '';
+    let wireBytes = 0;
+    let sseFrames = 0;
+    const nextFrame = async (): Promise<{ event: string; data: unknown }> => {
+      while (!buffered.includes('\n\n')) {
+        const next = await reader.read();
+        if (next.done) throw new Error('Pressure SSE ended early');
+        buffered += decoder.decode(next.value, { stream: true });
+      }
+      const boundary = buffered.indexOf('\n\n');
+      const frame = buffered.slice(0, boundary);
+      buffered = buffered.slice(boundary + 2);
+      wireBytes += encoder.encode(`${frame}\n\n`).byteLength;
+      sseFrames += 1;
+      const event = frame.split('\n').find((line) => line.startsWith('event: '))?.slice(7) ?? '';
+      const data = frame.split('\n').find((line) => line.startsWith('data: '))?.slice(6) ?? 'null';
+      return { event, data: JSON.parse(data) as unknown };
+    };
+
+    try {
+      const initial = await nextFrame();
+      expect(initial.event).toBe('snapshot');
+      codingConversationStore.getState().applySnapshotEvent(
+        initial.data as CodingConversationSnapshotEvent,
+      );
+      let rendererTransactions = 0;
+      const unsubscribe = codingConversationStore.subscribe(() => {
+        rendererTransactions += 1;
+      });
+      let reactCommits = 0;
+      const view = render(
+        <Profiler id="pressure-timeline" onRender={() => { reactCommits += 1; }}>
+          <CodingConversationTimeline conversationId={conversation.id} />
+        </Profiler>,
+      );
+      const initialCommits = reactCommits;
+      if (!publish) throw new Error('Pressure runtime subscriber was not installed');
+      const latencies: number[] = [];
+      let runtimePatchItems = 0;
+      let patchBatches = 0;
+      for (let burst = 0; burst < 20; burst += 1) {
+        const startedAt = performance.now();
+        for (let offset = 0; offset < 5; offset += 1) {
+          const seq = burst * 5 + offset + 1;
+          runtimePatchItems += 1;
+          publish({
+            conversationId: conversation.id,
+            workerGeneration: 0,
+            seq,
+            at: Date.now(),
+            patch: pressurePatch(seq),
+          });
+        }
+        const frame = await nextFrame();
+        expect(frame.event).toBe('patch-batch');
+        const batch = frame.data as CodingConversationPatchBatchEvent;
+        patchBatches += 1;
+        expect(batch.items).toHaveLength(5);
+        await act(async () => {
+          codingConversationStore.getState().applyPatchBatchEvent(batch);
+        });
+        latencies.push(performance.now() - startedAt);
+      }
+      const measuredReactCommits = reactCommits - initialCommits;
+      const p95Ms = percentile95(latencies);
+      const metrics = {
+        runtimePatchItems,
+        patchBatches,
+        sseFrames,
+        rendererTransactions,
+        reactCommits: measuredReactCommits,
+        wireBytes,
+        mainToReactP95Ms: p95Ms,
+      };
+      console.info('REN-008 metrics', metrics);
+      expect(metrics.runtimePatchItems).toBe(100);
+      expect(metrics.wireBytes).toBeGreaterThan(100 * 1024);
+      expect(metrics.patchBatches).toBeLessThan(metrics.runtimePatchItems);
+      expect(metrics.rendererTransactions).toBe(metrics.patchBatches);
+      expect(metrics.reactCommits).toBeLessThan(metrics.runtimePatchItems);
+      expect(metrics.sseFrames).toBe(metrics.patchBatches + 1);
+      expect(metrics.mainToReactP95Ms).toBeLessThanOrEqual(50);
+      expect(codingConversationStore.getState()
+        .entriesByConversationId[conversation.id]?.reducer.snapshot?.cursor.seq).toBe(100);
+      view.unmount();
+      unsubscribe();
+    } finally {
+      controller.abort();
+      await reader.cancel().catch(() => undefined);
+      server.closeAllConnections();
+      await new Promise<void>((resolve) => server.close(() => resolve()));
+    }
+  });
+});
diff --git a/tests/unit/coding-conversations-store.test.tsx b/tests/unit/coding-conversations-store.test.tsx
index f01ff9d..7025054 100644
--- a/tests/unit/coding-conversations-store.test.tsx
+++ b/tests/unit/coding-conversations-store.test.tsx
@@ -705,6 +705,74 @@ describe('coding Conversation store', () => {
     });
   });
 
+  it('refreshes a target Snapshot once more when the first recovery response is still behind', async () => {
+    const firstRecovery = deferred<ConversationSnapshot>();
+    const secondRecovery = deferred<ConversationSnapshot>();
+    const getSnapshot = vi.fn()
+      .mockImplementationOnce(() => firstRecovery.promise)
+      .mockImplementationOnce(() => secondRecovery.promise);
+    const store = createCodingConversationStore({
+      getSnapshot,
+      openEvents: vi.fn(),
+      submitPrompt: vi.fn(),
+      createId: ids(),
+    });
+    store.getState().applySnapshotEvent(snapshotEvent(snapshot('conversation-a')));
+    store.getState().applyPatchBatchEvent(patchBatch('conversation-a', 3, [
+      { op: 'run.state', run: { status: 'running', runId: 'run-a' } },
+      {
+        op: 'context.replace',
+        context: { usedTokens: 20, contextWindow: 100, compaction: 'idle' },
+      },
+    ]));
+
+    firstRecovery.resolve(snapshot('conversation-a', 1, 1));
+    await waitFor(() => expect(getSnapshot).toHaveBeenCalledTimes(2));
+    expect(store.getState().entriesByConversationId['conversation-a'].loadState).toBe('recovering');
+
+    secondRecovery.resolve(snapshot('conversation-a', 1, 2));
+    await waitFor(() => {
+      expect(selectCodingConversationSnapshot('conversation-a')(store.getState()))
+        .toMatchObject({
+          cursor: { workerGeneration: 1, seq: 4 },
+          context: { usedTokens: 20, contextWindow: 100 },
+          run: { status: 'running', runId: 'run-a' },
+        });
+    });
+    expect(store.getState().entriesByConversationId['conversation-a'].loadState).toBe('live');
+  });
+
+  it('returns a repeatedly stale recovery Snapshot to a retryable error state', async () => {
+    const firstRecovery = deferred<ConversationSnapshot>();
+    const secondRecovery = deferred<ConversationSnapshot>();
+    const getSnapshot = vi.fn()
+      .mockImplementationOnce(() => firstRecovery.promise)
+      .mockImplementationOnce(() => secondRecovery.promise);
+    const store = createCodingConversationStore({
+      getSnapshot,
+      openEvents: vi.fn(),
+      submitPrompt: vi.fn(),
+      createId: ids(),
+    });
+    store.getState().applySnapshotEvent(snapshotEvent(snapshot('conversation-a')));
+    store.getState().applyPatchBatchEvent(patchEvent('conversation-a', 3, {
+      op: 'run.state',
+      run: { status: 'running', runId: 'run-a' },
+    }));
+
+    firstRecovery.resolve(snapshot('conversation-a', 1, 1));
+    await waitFor(() => expect(getSnapshot).toHaveBeenCalledTimes(2));
+    secondRecovery.resolve(snapshot('conversation-a', 1, 1));
+
+    await waitFor(() => {
+      expect(store.getState().entriesByConversationId['conversation-a']).toMatchObject({
+        loadState: 'error',
+        error: 'Conversation patch batch is not continuous',
+      });
+    });
+    expect(getSnapshot).toHaveBeenCalledTimes(2);
+  });
+
   it('does not rerender a selected timeline when a hidden Conversation streams', () => {
     const store = createCodingConversationStore({
       getSnapshot: vi.fn(),
diff --git a/tests/unit/pi-session-registry.test.ts b/tests/unit/pi-session-registry.test.ts
index 9d8bacc..7b2bb51 100644
--- a/tests/unit/pi-session-registry.test.ts
+++ b/tests/unit/pi-session-registry.test.ts
@@ -5,6 +5,7 @@ import { tmpdir } from 'node:os';
 import path from 'node:path';
 import { afterEach, describe, expect, it, vi } from 'vitest';
 import { createCodingConversationStore } from '../../electron/coding-projects/conversation-store';
+import { CodingProjectService } from '../../electron/coding-projects/project-service';
 import { createCodingProjectAgent } from '../../electron/coding-projects/project-config';
 import {
   createCodingProjectStore,
@@ -170,6 +171,74 @@ describe('Pi session registry', () => {
     ]));
   });
 
+  it('shares one project mutation queue with ProjectService metadata writes', async () => {
+    const projectPath = await mkdtemp(path.join(tmpdir(), 'makelore-pi-shared-conversations-'));
+    roots.push(projectPath);
+    const projectStore = createCodingProjectStore(createMemoryCodingProjectStorage(), {
+      createId: () => 'project-shared',
+      now: () => NOW,
+    });
+    await createLocalCodingProject({ projectPath, now: NOW }, projectStore);
+    await createCodingProjectAgent(projectPath, {
+      id: 'agent-a',
+      avatarId: 'avatar-01',
+      roleName: 'Implementer',
+      name: 'Agent A',
+      model: { accountId: 'account-a', modelId: 'model-a', thinkingLevel: 'medium' },
+      modelResolution: 'resolved',
+      responsibility: { mission: 'Implement', owns: [], boundaries: [], collaborators: [], principles: [] },
+    }, { now: NOW });
+    const conversationIds = [
+      'f47ac10b-58cc-4372-a567-0e02b2c3d484',
+      'f47ac10b-58cc-4372-a567-0e02b2c3d485',
+    ];
+    const sharedStore = createCodingConversationStore(projectPath, {
+      createId: () => conversationIds.shift() as string,
+      now: () => NOW,
+    });
+    const left = await sharedStore.create({
+      agentId: 'agent-a',
+      title: 'Left',
+      model: { accountId: 'account-a', modelId: 'model-a', thinkingLevel: 'medium' },
+      modelResolution: 'resolved',
+    });
+    const sharedProvider = vi.fn(() => sharedStore);
+    const projects = new CodingProjectService(projectStore, {
+      createConversationStore: sharedProvider,
+    });
+    const registry = new PiSessionRegistry({
+      projectStore,
+      createConversationStore: sharedProvider,
+    });
+
+    await Promise.all([
+      registry.ensureBinding({
+        conversationId: left.id,
+        projectId: 'project-shared',
+        agentId: 'agent-a',
+        title: left.title,
+        model: { model: left.model, modelResolution: left.modelResolution },
+      }, async () => ({ piSessionId: 'pi-left', sessionKey: 'key-left' })),
+      projects.conversationStore(projectPath).create({
+        agentId: 'agent-a',
+        title: 'Right',
+        model: { accountId: 'account-a', modelId: 'model-a', thinkingLevel: 'medium' },
+        modelResolution: 'resolved',
+      }),
+    ]);
+
+    const persisted = await sharedStore.read();
+    expect(projects.conversationStore(projectPath)).toBe(sharedStore);
+    expect(persisted.conversations).toEqual(expect.arrayContaining([
+      expect.objectContaining({
+        id: left.id,
+        piSessionId: 'pi-left',
+        sessionKey: 'key-left',
+      }),
+      expect.objectContaining({ title: 'Right', agentId: 'agent-a' }),
+    ]));
+  });
+
   it('maps first session binding persistence failure to the stable storage error', async () => {
     const projectPath = await mkdtemp(path.join(tmpdir(), 'makelore-pi-registry-binding-failure-'));
     roots.push(projectPath);