fix: fail fast on missing host IPC dir for task runtimes

runners/agent-runner/src/ipc-mcp-stdio.ts

@@ -15,9 +15,10 @@ import {
   DEFAULT_WATCH_CI_CONTEXT_MODE,
   normalizeWatchCiIntervalSeconds,
 } from './watch-ci.js';
+import { resolveIpcDirectories } from './ipc-paths.js';
 
-const IPC_DIR = process.env.EJCLAW_IPC_DIR || '/workspace/ipc';
-const HOST_IPC_DIR = process.env.EJCLAW_HOST_IPC_DIR || IPC_DIR;
+const { ipcDir: IPC_DIR, hostIpcDir: HOST_IPC_DIR } =
+  resolveIpcDirectories(process.env);
 const MESSAGES_DIR = path.join(HOST_IPC_DIR, 'messages');
 const TASKS_DIR = path.join(HOST_IPC_DIR, 'tasks');
 

runners/agent-runner/src/ipc-paths.ts

@@ -0,0 +1,29 @@
+import path from 'path';
+
+export interface ResolvedIpcDirectories {
+  ipcDir: string;
+  hostIpcDir: string;
+}
+
+export function isTaskScopedIpcDir(ipcDir: string): boolean {
+  const normalized = path.posix.normalize(ipcDir.replaceAll('\\', '/'));
+  return /\/tasks\/[^/]+\/?$/.test(normalized);
+}
+
+export function resolveIpcDirectories(
+  env: NodeJS.ProcessEnv,
+): ResolvedIpcDirectories {
+  const ipcDir = env.EJCLAW_IPC_DIR || '/workspace/ipc';
+  const hostIpcDir = env.EJCLAW_HOST_IPC_DIR;
+
+  if (!hostIpcDir && isTaskScopedIpcDir(ipcDir)) {
+    throw new Error(
+      'EJCLAW_HOST_IPC_DIR is required for task-scoped IPC runtimes',
+    );
+  }
+
+  return {
+    ipcDir,
+    hostIpcDir: hostIpcDir || ipcDir,
+  };
+}

runners/agent-runner/test/ipc-paths.test.ts

@@ -0,0 +1,45 @@
+import { describe, expect, it } from 'vitest';
+
+import {
+  isTaskScopedIpcDir,
+  resolveIpcDirectories,
+} from '../src/ipc-paths.js';
+
+describe('ipc path helpers', () => {
+  it('detects task-scoped IPC directories', () => {
+    expect(isTaskScopedIpcDir('/data/ipc/group/tasks/task-123')).toBe(true);
+    expect(isTaskScopedIpcDir('C:\\ipc\\group\\tasks\\task-123')).toBe(true);
+    expect(isTaskScopedIpcDir('/data/ipc/group')).toBe(false);
+  });
+
+  it('fails fast when task-scoped IPC is missing host IPC dir', () => {
+    expect(() =>
+      resolveIpcDirectories({
+        EJCLAW_IPC_DIR: '/data/ipc/group/tasks/task-123',
+      }),
+    ).toThrow(/EJCLAW_HOST_IPC_DIR is required/i);
+  });
+
+  it('allows group-scoped IPC to fall back to the local IPC dir', () => {
+    expect(
+      resolveIpcDirectories({
+        EJCLAW_IPC_DIR: '/data/ipc/group',
+      }),
+    ).toEqual({
+      ipcDir: '/data/ipc/group',
+      hostIpcDir: '/data/ipc/group',
+    });
+  });
+
+  it('keeps host and task IPC dirs distinct when both are provided', () => {
+    expect(
+      resolveIpcDirectories({
+        EJCLAW_IPC_DIR: '/data/ipc/group/tasks/task-123',
+        EJCLAW_HOST_IPC_DIR: '/data/ipc/group',
+      }),
+    ).toEqual({
+      ipcDir: '/data/ipc/group/tasks/task-123',
+      hostIpcDir: '/data/ipc/group',
+    });
+  });
+});