feat(core,desktop): M6-rest part 4 — typed IPC protocol + real handlers + renderer wiring

apps/desktop/electron/main.ts

@@ -16,10 +16,14 @@ import { dirname, join } from 'node:path';
 import { homedir } from 'node:os';
 import {
   CredentialsStore,
+  SessionManager,
+  discoverPlugins,
   loadSettings,
+  loadSkills,
   resolveCredentials,
   VERSION,
 } from '@deepcode/core';
+import { promises as fs } from 'node:fs';
 
 const __filename = fileURLToPath(import.meta.url);
 const __dirname = dirname(__filename);
@@ -82,6 +86,55 @@ ipcMain.handle('settings:load', async () => {
   return merged;
 });
 
+// ──────────────────────────────────────────────────────────────────────────
+// M6-rest IPC handlers — list sessions / plugins / skills / mcp
+// ──────────────────────────────────────────────────────────────────────────
+
+ipcMain.handle('sessions:list', async (_event, args: { limit?: number } = {}) => {
+  const sm = new SessionManager();
+  const all = await sm.list();
+  return all.slice(0, args.limit ?? 50);
+});
+
+ipcMain.handle('plugins:list', async () => {
+  const { plugins, hashMismatches } = await discoverPlugins({ home: homedir() });
+  return plugins.map((p) => ({
+    name: p.manifest.name,
+    version: p.manifest.version,
+    enabled: p.enabled,
+    sourceHash: p.sourceHash,
+    trustedBy: 'user', // proper trust map lookup belongs here once exposed
+    contributedHookEvents: Object.keys(p.manifest.contributes?.hooks ?? {}),
+    warning: hashMismatches.find((m) => m.startsWith(p.manifest.name)),
+  }));
+});
+
+ipcMain.handle('mcp:list', async () => {
+  // The actual MCP connect happens once the agent loop boots; here we surface
+  // the configured servers from settings as 'disabled' until then.
+  const { merged } = await loadSettings({ cwd: process.cwd(), home: homedir() });
+  const servers = merged.mcpServers ?? {};
+  return Object.keys(servers).map((name) => ({ name, status: 'disabled' as const }));
+});
+
+ipcMain.handle('skills:list', async () => {
+  const skills = await loadSkills({ cwd: process.cwd(), home: homedir() });
+  return skills.map((s) => ({
+    name: s.name,
+    description: s.description,
+    source: s.source,
+    path: s.path,
+  }));
+});
+
+ipcMain.handle('skills:body', async (_event, args: { path: string }) => {
+  try {
+    return await fs.readFile(args.path, 'utf8');
+  } catch (err) {
+    return `(error reading skill body: ${(err as Error).message})`;
+  }
+});
+
 // ──────────────────────────────────────────────────────────────────────────
 // electron-updater — lazy import so the skeleton works without the dep
 // ──────────────────────────────────────────────────────────────────────────

apps/desktop/electron/preload.ts

@@ -1,31 +1,109 @@
 // Electron preload — bridges renderer to the trusted main process via
 // contextBridge. The renderer can ONLY call these exposed APIs; raw `require`
 // and Node globals are disabled.
-// Spec: docs/DEVELOPMENT_PLAN.md §4
-// Milestone: M6
+// Spec: docs/DEVELOPMENT_PLAN.md §4 + packages/core/src/ipc/protocol.ts
+// Milestone: M6 + M6-rest
 
 import { contextBridge, ipcRenderer } from 'electron';
 
 const api = {
   version: (): Promise<string> => ipcRenderer.invoke('app:version'),
+
   creds: {
     load: (): Promise<{ hasKey: boolean; baseURL?: string }> =>
       ipcRenderer.invoke('creds:load'),
     save: (args: { apiKey: string; baseURL?: string }): Promise<boolean> =>
       ipcRenderer.invoke('creds:save', args),
   },
+
   settings: {
     load: (): Promise<Record<string, unknown>> => ipcRenderer.invoke('settings:load'),
   },
+
+  sessions: {
+    list: (
+      args: { limit?: number } = {},
+    ): Promise<
+      Array<{ id: string; title?: string; cwd: string; updatedAt: string; model?: string }>
+    > => ipcRenderer.invoke('sessions:list', args),
+    resume: (
+      args: { id: string },
+    ): Promise<{ history: unknown[]; sessionId: string }> =>
+      ipcRenderer.invoke('sessions:resume', args),
+  },
+
+  plugins: {
+    list: (): Promise<
+      Array<{
+        name: string;
+        version: string;
+        enabled: boolean;
+        sourceHash: string;
+        trustedBy: 'user' | 'marketplace' | 'official';
+        contributedHookEvents: string[];
+      }>
+    > => ipcRenderer.invoke('plugins:list'),
+    install: (args: { spec: string }): Promise<{ name: string; version: string }> =>
+      ipcRenderer.invoke('plugins:install', args),
+    setEnabled: (args: { name: string; enabled: boolean }): Promise<boolean> =>
+      ipcRenderer.invoke('plugins:setEnabled', args),
+  },
+
+  mcp: {
+    list: (): Promise<
+      Array<{
+        name: string;
+        status: 'connected' | 'failed' | 'disabled';
+        toolCount?: number;
+        error?: string;
+      }>
+    > => ipcRenderer.invoke('mcp:list'),
+  },
+
+  skills: {
+    list: (): Promise<
+      Array<{
+        name: string;
+        description: string;
+        source: 'builtin' | 'user' | 'project' | 'plugin';
+        path: string;
+      }>
+    > => ipcRenderer.invoke('skills:list'),
+    body: (args: { path: string }): Promise<string> => ipcRenderer.invoke('skills:body', args),
+  },
+
+  agent: {
+    start: (args: {
+      sessionId: string;
+      userMessage: string;
+      mode?: string;
+      model?: string;
+      allowedTools?: string[];
+    }): Promise<{ turnId: string }> => ipcRenderer.invoke('agent:start', args),
+    abort: (args: { turnId: string }): Promise<boolean> =>
+      ipcRenderer.invoke('agent:abort', args),
+    approve: (args: { turnId: string; toolCallId: string; allow: boolean }): Promise<void> =>
+      ipcRenderer.invoke('agent:approve', args),
+    answer: (args: { turnId: string; questionId: string; answer: string }): Promise<void> =>
+      ipcRenderer.invoke('agent:answer', args),
+    onEvent: (cb: (e: unknown) => void): (() => void) => {
+      const listener = (_event: unknown, payload: unknown) => cb(payload);
+      ipcRenderer.on('agent:event', listener);
+      return () => ipcRenderer.removeListener('agent:event', listener);
+    },
+  },
+
   /** Subscribe to "update downloaded" events from the auto-updater. */
-  onUpdateDownloaded: (cb: (info: { version: string; releaseNotes?: string }) => void): (() => void) => {
-    const listener = (_e: unknown, info: { version: string; releaseNotes?: string }) => cb(info);
+  onUpdateDownloaded: (
+    cb: (info: { version: string; releaseNotes?: string }) => void,
+  ): (() => void) => {
+    const listener = (_e: unknown, info: { version: string; releaseNotes?: string }) =>
+      cb(info);
     ipcRenderer.on('updater:update-downloaded', listener);
     return () => ipcRenderer.removeListener('updater:update-downloaded', listener);
   },
 };
 
 contextBridge.exposeInMainWorld('deepcode', api);
 
-// Type declaration for the renderer (mirrored manually in src/types/global.d.ts)
 export type DeepCodeRendererAPI = typeof api;

apps/desktop/src/screens/MCPManager.tsx

@@ -15,8 +15,14 @@ export function MCPManagerScreen(): JSX.Element {
   const [servers, setServers] = useState<McpServerStatus[] | null>(null);
 
   useEffect(() => {
-    // Real impl: window.deepcode.mcp.list() — wired in M6-rest IPC PR.
-    setServers([]);
+    if (window.deepcode?.mcp?.list) {
+      void window.deepcode.mcp
+        .list()
+        .then((rows) => setServers(rows as McpServerStatus[]))
+        .catch(() => setServers([]));
+    } else {
+      setServers([]);
+    }
   }, []);
 
   if (servers === null) {

apps/desktop/src/screens/Plugins.tsx

@@ -21,8 +21,14 @@ export function PluginsScreen(): JSX.Element {
   const [installing, setInstalling] = useState(false);
 
   useEffect(() => {
-    // Real impl: window.deepcode.plugins.list() — wired in IPC PR.
-    setPlugins([]);
+    if (window.deepcode?.plugins?.list) {
+      void window.deepcode.plugins
+        .list()
+        .then((rows) => setPlugins(rows as PluginRow[]))
+        .catch(() => setPlugins([]));
+    } else {
+      setPlugins([]);
+    }
   }, []);
 
   async function handleInstall(): Promise<void> {

apps/desktop/src/screens/Sessions.tsx

@@ -23,9 +23,15 @@ export function SessionsScreen({ onPick, onNew }: SessionsProps): JSX.Element {
   const [filter, setFilter] = useState('');
 
   useEffect(() => {
-    // Real impl wires through window.deepcode.sessions.list — added in
-    // M6-rest IPC PR. For now, render an empty state.
-    setSessions([]);
+    // IPC call; fall back to empty list when main hasn't implemented yet.
+    if (window.deepcode?.sessions?.list) {
+      void window.deepcode.sessions
+        .list()
+        .then((rows) => setSessions(rows as SessionMeta[]))
+        .catch(() => setSessions([]));
+    } else {
+      setSessions([]);
+    }
   }, []);
 
   if (sessions === null) {

apps/desktop/src/screens/Skills.tsx

@@ -19,8 +19,14 @@ export function SkillsScreen(): JSX.Element {
   const [filter, setFilter] = useState('');
 
   useEffect(() => {
-    // Real impl: window.deepcode.skills.list() — wired in IPC PR.
-    setSkills([]);
+    if (window.deepcode?.skills?.list) {
+      void window.deepcode.skills
+        .list()
+        .then((rows) => setSkills(rows as SkillRow[]))
+        .catch(() => setSkills([]));
+    } else {
+      setSkills([]);
+    }
   }, []);
 
   if (skills === null) {

apps/desktop/src/types/global.d.ts

@@ -5,6 +5,37 @@ export interface UpdateInfo {
   releaseNotes?: string;
 }
 
+export interface SessionListEntry {
+  id: string;
+  title?: string;
+  cwd: string;
+  updatedAt: string;
+  model?: string;
+}
+
+export interface PluginRow {
+  name: string;
+  version: string;
+  enabled: boolean;
+  sourceHash: string;
+  trustedBy: 'user' | 'marketplace' | 'official';
+  contributedHookEvents: string[];
+}
+
+export interface McpServerRow {
+  name: string;
+  status: 'connected' | 'failed' | 'disabled';
+  toolCount?: number;
+  error?: string;
+}
+
+export interface SkillRow {
+  name: string;
+  description: string;
+  source: 'builtin' | 'user' | 'project' | 'plugin';
+  path: string;
+}
+
 export interface DeepCodeAPI {
   version: () => Promise<string>;
   creds: {
@@ -14,6 +45,35 @@ export interface DeepCodeAPI {
   settings: {
     load: () => Promise<Record<string, unknown>>;
   };
+  sessions: {
+    list: (args?: { limit?: number }) => Promise<SessionListEntry[]>;
+    resume: (args: { id: string }) => Promise<{ history: unknown[]; sessionId: string }>;
+  };
+  plugins: {
+    list: () => Promise<PluginRow[]>;
+    install: (args: { spec: string }) => Promise<{ name: string; version: string }>;
+    setEnabled: (args: { name: string; enabled: boolean }) => Promise<boolean>;
+  };
+  mcp: {
+    list: () => Promise<McpServerRow[]>;
+  };
+  skills: {
+    list: () => Promise<SkillRow[]>;
+    body: (args: { path: string }) => Promise<string>;
+  };
+  agent: {
+    start: (args: {
+      sessionId: string;
+      userMessage: string;
+      mode?: string;
+      model?: string;
+      allowedTools?: string[];
+    }) => Promise<{ turnId: string }>;
+    abort: (args: { turnId: string }) => Promise<boolean>;
+    approve: (args: { turnId: string; toolCallId: string; allow: boolean }) => Promise<void>;
+    answer: (args: { turnId: string; questionId: string; answer: string }) => Promise<void>;
+    onEvent: (cb: (e: unknown) => void) => () => void;
+  };
   onUpdateDownloaded: (cb: (info: UpdateInfo) => void) => () => void;
 }
 

packages/core/src/index.ts

@@ -241,6 +241,19 @@ export {
   type MarketplaceConfig,
 } from './plugins/index.js';
 
+// IPC protocol (M6-rest — renderer ↔ main process type-safe channels)
+export {
+  newTurnId,
+  newQuestionId,
+  type IpcChannel,
+  type IpcEventChannel,
+  type IpcRequest,
+  type IpcResponse,
+  type IpcRequestMap,
+  type IpcEventMap,
+  type AgentStreamEvent,
+} from './ipc/protocol.js';
+
 // Voice input (M8 — whisper.cpp wrapper + stub provider)
 export {
   WhisperCppProvider,

packages/core/src/ipc/protocol.test.ts

@@ -0,0 +1,24 @@
+import { describe, expect, it } from 'vitest';
+import { newQuestionId, newTurnId } from './protocol.js';
+
+describe('newTurnId', () => {
+  it('returns turn-<base36 ts>-<random>', () => {
+    const id = newTurnId();
+    expect(id).toMatch(/^turn-[0-9a-z]+-[0-9a-z]+$/);
+  });
+  it('produces unique ids across rapid calls', () => {
+    const set = new Set(Array.from({ length: 50 }, newTurnId));
+    expect(set.size).toBe(50);
+  });
+});
+
+describe('newQuestionId', () => {
+  it('returns q-<base36 ts>-<random>', () => {
+    const id = newQuestionId();
+    expect(id).toMatch(/^q-[0-9a-z]+-[0-9a-z]+$/);
+  });
+  it('produces unique ids', () => {
+    const set = new Set(Array.from({ length: 50 }, newQuestionId));
+    expect(set.size).toBe(50);
+  });
+});