feat(01.1-06): add tRPC HTTP adapter and CLI client

- Create src/server/trpc-adapter.ts with fetch adapter for node:http
- Create src/cli/trpc-client.ts with typed client factory functions
- Update CoordinationServer to route /trpc/* to tRPC handler
- Move @trpc/client from devDeps to regular deps
- Keep /health and /status HTTP endpoints for backwards compatibility

src/cli/trpc-client.ts

@@ -0,0 +1,54 @@
+/**
+ * tRPC Client for CLI
+ *
+ * Type-safe client for communicating with the coordination server.
+ * Uses httpBatchLink for efficient request batching.
+ */
+
+import { createTRPCClient, httpBatchLink } from '@trpc/client';
+import type { AppRouter } from '../trpc/index.js';
+
+/** Default server port */
+const DEFAULT_PORT = 3847;
+
+/** Default server host */
+const DEFAULT_HOST = '127.0.0.1';
+
+/**
+ * Type-safe tRPC client for the coordination server.
+ */
+export type TrpcClient = ReturnType<typeof createTRPCClient<AppRouter>>;
+
+/**
+ * Creates a tRPC client for the coordination server.
+ *
+ * @param port - Server port (default: 3847)
+ * @param host - Server host (default: 127.0.0.1)
+ * @returns Type-safe tRPC client
+ */
+export function createTrpcClient(
+  port: number = DEFAULT_PORT,
+  host: string = DEFAULT_HOST
+): TrpcClient {
+  return createTRPCClient<AppRouter>({
+    links: [
+      httpBatchLink({
+        url: `http://${host}:${port}/trpc`,
+      }),
+    ],
+  });
+}
+
+/**
+ * Creates a tRPC client using environment variables or defaults.
+ *
+ * Uses CW_PORT and CW_HOST environment variables if available,
+ * falling back to defaults (127.0.0.1:3847).
+ *
+ * @returns Type-safe tRPC client
+ */
+export function createDefaultTrpcClient(): TrpcClient {
+  const port = process.env.CW_PORT ? parseInt(process.env.CW_PORT, 10) : DEFAULT_PORT;
+  const host = process.env.CW_HOST ?? DEFAULT_HOST;
+  return createTrpcClient(port, host);
+}

src/server/index.ts

@@ -3,6 +3,7 @@
  *
  * HTTP server with health endpoint for agent coordination.
  * Uses native node:http for minimal dependencies.
+ * Supports both traditional HTTP endpoints and tRPC for type-safe client communication.
  */
 
 import { createServer, type Server, type IncomingMessage, type ServerResponse } from 'node:http';
@@ -14,6 +15,7 @@ import type { ServerConfig, ServerState, HealthResponse, StatusResponse } from '
 import type { ProcessManager } from '../process/index.js';
 import type { LogManager } from '../logging/index.js';
 import type { EventBus, ServerStartedEvent, ServerStoppedEvent } from '../events/index.js';
+import { createTrpcHandler } from './trpc-adapter.js';
 
 /** Default port for the coordination server */
 const DEFAULT_PORT = 3847;
@@ -180,14 +182,22 @@ export class CoordinationServer {
    * Handles incoming HTTP requests with simple path matching.
    */
   private handleRequest(req: IncomingMessage, res: ServerResponse): void {
-    // Only accept GET requests
+    const url = req.url ?? '/';
+
+    // Route tRPC requests to tRPC handler
+    if (url.startsWith('/trpc')) {
+      this.handleTrpc(req, res);
+      return;
+    }
+
+    // Only accept GET requests for non-tRPC routes
     if (req.method !== 'GET') {
       this.sendJson(res, 405, { error: 'Method not allowed' });
       return;
     }
 
-    // Simple path routing
-    switch (req.url) {
+    // Simple path routing for backwards-compatible HTTP endpoints
+    switch (url) {
       case '/health':
         this.handleHealth(res);
         break;
@@ -199,6 +209,27 @@ export class CoordinationServer {
     }
   }
 
+  /**
+   * Handles tRPC requests via the fetch adapter.
+   */
+  private handleTrpc(req: IncomingMessage, res: ServerResponse): void {
+    if (!this.state || !this.eventBus) {
+      this.sendJson(res, 500, { error: 'Server not initialized or missing eventBus' });
+      return;
+    }
+
+    const trpcHandler = createTrpcHandler({
+      eventBus: this.eventBus,
+      serverStartedAt: this.state.startedAt,
+      processCount: this.state.processCount,
+    });
+
+    trpcHandler(req, res).catch((error: Error) => {
+      console.error('tRPC handler error:', error);
+      this.sendJson(res, 500, { error: 'Internal server error' });
+    });
+  }
+
   /**
    * Handles GET /health endpoint.
    */

src/server/trpc-adapter.ts

@@ -0,0 +1,99 @@
+/**
+ * tRPC HTTP Adapter
+ *
+ * Handles tRPC requests over HTTP using node:http.
+ * Routes /trpc/* requests to the tRPC router.
+ */
+
+import type { IncomingMessage, ServerResponse } from 'node:http';
+import { fetchRequestHandler } from '@trpc/server/adapters/fetch';
+import { appRouter, createContext } from '../trpc/index.js';
+import type { EventBus } from '../events/index.js';
+
+/**
+ * Options for creating the tRPC request handler.
+ */
+export interface TrpcAdapterOptions {
+  /** Event bus for inter-module communication */
+  eventBus: EventBus;
+  /** When the server started */
+  serverStartedAt: Date;
+  /** Number of managed processes */
+  processCount: number;
+}
+
+/**
+ * Creates a tRPC request handler for node:http.
+ *
+ * Converts IncomingMessage/ServerResponse to fetch Request/Response
+ * and delegates to the tRPC fetch adapter.
+ *
+ * @param options - Adapter options with context values
+ * @returns Request handler function
+ */
+export function createTrpcHandler(options: TrpcAdapterOptions) {
+  return async (req: IncomingMessage, res: ServerResponse): Promise<void> => {
+    // Build full URL from request
+    const protocol = 'http';
+    const host = req.headers.host ?? 'localhost';
+    const url = new URL(req.url ?? '/', `${protocol}://${host}`);
+
+    // Read request body if present
+    let body: string | undefined;
+    if (req.method !== 'GET' && req.method !== 'HEAD') {
+      body = await new Promise<string>((resolve) => {
+        let data = '';
+        req.on('data', (chunk: Buffer) => {
+          data += chunk.toString();
+        });
+        req.on('end', () => {
+          resolve(data);
+        });
+      });
+    }
+
+    // Convert headers to fetch Headers
+    const headers = new Headers();
+    for (const [key, value] of Object.entries(req.headers)) {
+      if (value) {
+        if (Array.isArray(value)) {
+          value.forEach((v) => headers.append(key, v));
+        } else {
+          headers.set(key, value);
+        }
+      }
+    }
+
+    // Create fetch Request
+    const fetchRequest = new Request(url.toString(), {
+      method: req.method,
+      headers,
+      body: body ?? undefined,
+    });
+
+    // Handle with tRPC fetch adapter
+    const fetchResponse = await fetchRequestHandler({
+      endpoint: '/trpc',
+      req: fetchRequest,
+      router: appRouter,
+      createContext: () =>
+        createContext({
+          eventBus: options.eventBus,
+          serverStartedAt: options.serverStartedAt,
+          processCount: options.processCount,
+        }),
+    });
+
+    // Send response
+    res.statusCode = fetchResponse.status;
+
+    // Set response headers
+    fetchResponse.headers.forEach((value, key) => {
+      res.setHeader(key, value);
+    });
+
+    // Send body
+    const responseBody = await fetchResponse.text();
+    res.end(responseBody);
+  };
+}