diff --git a/src/store.ts b/src/store.ts
index 12be84b..ccb8cff 100644
--- a/src/store.ts
+++ b/src/store.ts
@@ -817,7 +817,7 @@ export const store = {
     }
     // U4/R5：已保存页面从权威快照重载（刷新/断线恢复；事件流只做增量投影）。
     // surfaceList 返回扁平 SurfaceMeta，不可写入 surfaces；必须经 surfaceGet 水合为 Snapshot。
-    api.projectSurfaces(state.currentProjectId ?? '').then(list => { if (state.currentConvId === convId && conversationEpoch === epoch) set({ projectSurfaces: list ?? [] }) }).catch(() => {})
+    if (state.currentProjectId) api.projectSurfaces(state.currentProjectId).then(list => { if (state.currentConvId === convId && conversationEpoch === epoch) set({ projectSurfaces: list ?? [] }) }).catch(() => {})
     api.surfaceList(convId).then(async list => {
       if (state.currentConvId !== convId || conversationEpoch !== epoch) return
       const metas = list ?? []
diff --git a/test/open-conversation-no-project.test.ts b/test/open-conversation-no-project.test.ts
new file mode 100644
index 0000000..759027e
--- /dev/null
+++ b/test/open-conversation-no-project.test.ts
@@ -0,0 +1,64 @@
+// ps-frontend-no-project-surfaces-r2：openConversation 在 state.currentProjectId 为空时
+// 不再触发 /api/projects/<id>/surfaces 请求（避免被移除项目成员打开历史会话时的 404 噪音）。
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+import { api } from '../src/api'
+import { store } from '../src/store'
+import type { Conversation, Message, SurfaceMeta } from '../src/contracts'
+
+function detail(id: string) {
+  return {
+    conversation: { id, projectId: '', title: id, createdAt: '', updatedAt: '' } as Conversation,
+    messages: [] as Message[], runs: [], activeHitl: [], lastSeq: 0, resumeSeq: 0,
+  }
+}
+class FakeEventSource {
+  onopen = null
+  onerror = null
+  onmessage = null
+  addEventListener() {}
+  close() {}
+}
+
+let projectSurfacesSpy: ReturnType<typeof vi.spyOn>
+
+beforeEach(async () => {
+  vi.stubGlobal('EventSource', FakeEventSource)
+  vi.spyOn(api, 'conversationDetail').mockImplementation(async id => detail(id))
+  vi.spyOn(api, 'getPlan').mockResolvedValue(null)
+  vi.spyOn(api, 'getTodos').mockResolvedValue(null)
+  vi.spyOn(api, 'listCards').mockResolvedValue([])
+  vi.spyOn(api, 'listTasks').mockResolvedValue([])
+  vi.spyOn(api, 'listArtifacts').mockResolvedValue([])
+  vi.spyOn(api, 'surfaceList').mockResolvedValue([])
+  projectSurfacesSpy = vi.spyOn(api, 'projectSurfaces').mockResolvedValue([])
+  vi.spyOn(api, 'listProjectCards').mockResolvedValue([])
+  // 还原至 currentProjectId = null 的干净投影，避免别的套件残留影响本次断言。
+  store.resetIdentity()
+})
+afterEach(() => { vi.useRealTimers(); vi.restoreAllMocks(); vi.unstubAllGlobals() })
+
+describe('openConversation projectSurfaces gating', () => {
+  it('skips the /api/projects/.../surfaces request and keeps projectSurfaces empty when no project is current', async () => {
+    expect(store.getState().currentProjectId).toBeNull()
+    await store.openConversation('cnv_no_project')
+    // 让微任务（包含 surfaceList/Stream 等链）落定，但不改变当前结论。
+    await new Promise(r => setTimeout(r, 0))
+    expect(projectSurfacesSpy).not.toHaveBeenCalled()
+    expect(store.getState().projectSurfaces).toEqual([])
+    expect(store.getState().currentProjectId).toBeNull()
+  })
+
+  it('still requests /api/projects/<id>/surfaces when a project is current', async () => {
+    const metas: SurfaceMeta[] = [{ surfaceId: 'surf_1', title: '页面一', pluginId: 'plg_1', revision: 1, updatedAt: '2026-10-12T00:00:00Z' }]
+    projectSurfacesSpy.mockResolvedValueOnce(metas)
+    await store.openProject('prj_with_surfaces')
+    expect(store.getState().currentProjectId).toBe('prj_with_surfaces')
+    projectSurfacesSpy.mockClear()
+    await store.openConversation('cnv_with_project')
+    expect(projectSurfacesSpy).toHaveBeenCalledTimes(1)
+    expect(projectSurfacesSpy.mock.calls[0][0]).toBe('prj_with_surfaces')
+    // 微任务处理完 .then 后，projectSurfaces 投影被填进服务端的元数据列表。
+    await new Promise(r => setTimeout(r, 0))
+    expect(store.getState().projectSurfaces).toEqual(metas)
+  })
+})