2.2.1

changelog.md

@@ -1,5 +1,50 @@
 # Changelog
 
+## 2025-08-29 - 2.2.1 - fix(tests)
+Remove redundant manual topic handlers from tests and rely on server built-in pub/sub
+
+- Removed manual server.onMessage('__subscribe__') and server.onMessage('__publish__') handlers from test/test.ts
+- Tests now rely on the server's built-in publish/subscribe behavior: clients publish directly and subscribers receive messages
+- Test code simplified without changing public API or runtime behavior
+
+## 2025-08-29 - 2.2.0 - feat(ipcclient)
+Add clientOnly mode to prevent clients from auto-starting servers and improve registration/reconnect behavior
+
+- Introduce a clientOnly option on transports and clients, and support SMARTIPC_CLIENT_ONLY=1 env override to prevent a client from auto-starting a server when connect() encounters ECONNREFUSED/ENOENT.
+- Update UnixSocketTransport/TcpTransport connect behavior: if clientOnly (or env override) is enabled, reject connect with a descriptive error instead of starting a server (preserves backward compatibility when disabled).
+- Make SmartIpc.waitForServer use clientOnly probing to avoid accidental server creation during readiness checks.
+- Refactor IpcClient registration flow: extract attemptRegistrationInternal, set didRegisterOnce flag, and automatically re-register on reconnects when previously registered.
+- Add and update tests to cover clientOnly behavior, SMARTIPC_CLIENT_ONLY env enforcement, temporary socket paths and automatic cleanup, and other reliability improvements.
+- Update README with a new 'Client-Only Mode' section documenting the option, env override, and examples.
+
+## 2025-08-28 - 2.1.3 - fix(classes.ipcchannel)
+Normalize heartbeatThrowOnTimeout option parsing and allow registering 'heartbeatTimeout' via IpcChannel.on
+
+- Normalize heartbeatThrowOnTimeout to boolean (accepts 'true'/'false' strings and other truthy/falsey values) to be defensive for JS consumers
+- Expose 'heartbeatTimeout' as a special channel event so handlers registered via IpcChannel.on('heartbeatTimeout', ...) will be called
+
+## 2025-08-26 - 2.1.2 - fix(core)
+Improve heartbeat handling and transport routing; forward heartbeat timeout events; include clientId routing and probe improvements
+
+- IpcChannel: add heartbeatInitialGracePeriod handling — delay heartbeat timeout checks until the grace period elapses and use a minimum check interval (>= 1000ms)
+- IpcChannel: add heartbeatGraceTimer and ensure stopHeartbeat clears the grace timer to avoid repeated events
+- IpcChannel / Client / Server: forward heartbeatTimeout events instead of only throwing when configured (heartbeatThrowOnTimeout = false) so consumers can handle timeouts via events
+- IpcClient: include clientId in registration request headers to enable proper routing on the server/transport side
+- UnixSocketTransport: track socket <-> clientId mappings, clean them up on socket close, and update mappings when __register__ or messages containing clientId are received
+- UnixSocketTransport: route messages to a specific client when headers.clientId is present (fallback to broadcasting when no target is found), and emit both clientMessage and message for parsed client messages
+- ts/index.waitForServer: use SmartIpc.createClient for probing, shorten probe register timeout, and use a slightly longer retry delay between probes for stability
+
+## 2025-08-25 - 2.1.1 - fix(readme)
+Update README: expand docs, examples, server readiness, heartbeat, and testing utilities
+
+- Rewrite introduction and overall tone to emphasize zero-dependency, reliability, and TypeScript support
+- Replace several Quick Start examples to use socketPath and show autoCleanupSocketFile usage
+- Add Server readiness detection docs and SmartIpc.waitForServer example
+- Document smart connection retry options (connectRetry) and registerTimeoutMs usage
+- Clarify heartbeat configuration and add heartbeatThrowOnTimeout option to emit events instead of throwing
+- Add sections for automatic socket cleanup, broadcasting, testing utilities (waitForServer, spawnAndConnect), and metrics
+- Various formatting and copy improvements throughout README
+
 ## 2025-08-25 - 2.1.0 - feat(core)
 Add heartbeat grace/timeout options, client retry/wait-for-ready, server readiness and socket cleanup, transport socket options, helper utilities, and tests
 
@@ -53,4 +98,11 @@ Metadata and configuration updates; repository/org migration.
 Initial release and a series of patch fixes to core components.
 
 - 1.0.1: initial release.
-- 1.0.2 → 1.0.7: a sequence of small core fixes and maintenance updates (repeated "fix(core): update" commits).
+- 1.0.2 → 1.0.7: a sequence of small core fixes and maintenance updates (repeated "fix(core): update" commits).
+## 2025-08-29 - 2.1.4 - feat(transports)
+Add client-only mode to prevent unintended server auto-start in Unix/NamedPipe transports; safer probing
+
+- Add `clientOnly?: boolean` to transport options; when true (or `SMARTIPC_CLIENT_ONLY=1`), a client will fail fast on `ECONNREFUSED`/`ENOENT` instead of auto-starting a server.
+- Update `SmartIpc.waitForServer()` to probe with `clientOnly: true` to avoid races during readiness checks.
+- Extend tests to cover option and env override; update core test to use unique socket path and auto-cleanup.
+- Docs: add README section for client-only mode.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@push.rocks/smartipc",
-  "version": "2.1.0",
+  "version": "2.2.1",
   "private": false,
   "description": "A library for node inter process communication, providing an easy-to-use API for IPC.",
   "exports": {

readme.md

@@ -1,34 +1,33 @@
 # @push.rocks/smartipc 🚀
 
-**Lightning-fast, type-safe IPC for modern Node.js applications**
+**Rock-solid IPC for Node.js with zero dependencies**
 
 [![npm version](https://img.shields.io/npm/v/@push.rocks/smartipc.svg)](https://www.npmjs.com/package/@push.rocks/smartipc)
 [![TypeScript](https://img.shields.io/badge/TypeScript-5.x-blue.svg)](https://www.typescriptlang.org/)
 [![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](./license)
 
-SmartIPC is a production-grade Inter-Process Communication library that brings enterprise-level messaging patterns to Node.js. Built with TypeScript from the ground up, it offers zero-dependency native IPC with automatic reconnection, type-safe messaging, and built-in observability.
+SmartIPC delivers bulletproof Inter-Process Communication for Node.js applications. Built for real-world production use, it handles all the edge cases that make IPC tricky - automatic reconnection, race conditions, heartbeat monitoring, and clean shutdowns. All with **zero external dependencies** and full TypeScript support.
 
-## Why SmartIPC?
+## 🎯 Why SmartIPC?
 
-- **🎯 Zero External Dependencies** - Pure Node.js implementation using native `net` module
-- **🔒 Type-Safe** - Full TypeScript support with generics for compile-time safety
-- **🔄 Auto-Reconnect** - Built-in exponential backoff and circuit breaker patterns
-- **📊 Observable** - Real-time metrics and connection tracking
-- **⚡ High Performance** - Length-prefixed framing, backpressure handling, and optimized buffers
-- **🎭 Multiple Patterns** - Request/Response, Pub/Sub, and Fire-and-Forget messaging
-- **🛡️ Production Ready** - Message size limits, heartbeat monitoring, and graceful shutdown
+- **Zero Dependencies** - Pure Node.js implementation using native modules
+- **Battle-tested Reliability** - Automatic reconnection, graceful degradation, and timeout handling
+- **Type-Safe** - Full TypeScript support with generics for compile-time safety
+- **CI/Test Ready** - Built-in helpers and race condition prevention for testing
+- **Observable** - Real-time metrics, connection tracking, and health monitoring
+- **Multiple Patterns** - Request/Response, Pub/Sub, and Fire-and-Forget messaging
 
-## Installation
+## 📦 Installation
 
 ```bash
+npm install @push.rocks/smartipc
+# or
 pnpm add @push.rocks/smartipc
 # or
-npm install @push.rocks/smartipc
+yarn add @push.rocks/smartipc
 ```
 
-## Quick Start
-
-### Simple TCP Server & Client
+## 🚀 Quick Start
 
 ```typescript
 import { SmartIpc } from '@push.rocks/smartipc';
@@ -36,34 +35,42 @@ import { SmartIpc } from '@push.rocks/smartipc';
 // Create a server
 const server = SmartIpc.createServer({
   id: 'my-service',
-  host: 'localhost',
-  port: 9876
+  socketPath: '/tmp/my-service.sock',
+  autoCleanupSocketFile: true  // Clean up stale sockets automatically
 });
 
 // Handle incoming messages
-server.onMessage('hello', async (data, clientId) => {
-  console.log(`Client ${clientId} says:`, data);
-  return { response: 'Hello back!' };
+server.onMessage('greet', async (data, clientId) => {
+  console.log(`Client ${clientId} says:`, data.message);
+  return { response: `Hello ${data.name}!` };
 });
 
-await server.start();
+// Start the server
+await server.start({ readyWhen: 'accepting' });  // Wait until fully ready
+console.log('Server is ready to accept connections! ✨');
 
 // Create a client
 const client = SmartIpc.createClient({
   id: 'my-service',
-  host: 'localhost', 
-  port: 9876,
-  clientId: 'client-1'
+  socketPath: '/tmp/my-service.sock',
+  connectRetry: {
+    enabled: true,
+    maxAttempts: 10
+  }
 });
 
+// Connect with automatic retry
 await client.connect();
 
-// Send a message and get response
-const response = await client.request('hello', { message: 'Hi server!' });
-console.log('Server responded:', response);
+// Send a request and get a response
+const response = await client.request('greet', { 
+  name: 'World',
+  message: 'Hi there!' 
+});
+console.log('Server said:', response.response);  // "Hello World!"
 ```
 
-## Core Concepts
+## 🎮 Core Concepts
 
 ### Transport Types
 
@@ -84,350 +91,423 @@ const unixServer = SmartIpc.createServer({
 });
 
 // Windows Named Pipe (Windows optimal)
-const pipeServer = SmartIpc.createServer({
+// Automatically used on Windows when socketPath is provided
+const windowsServer = SmartIpc.createServer({
   id: 'pipe-service',
-  pipeName: 'my-app-pipe'
+  socketPath: '\\\\.\\pipe\\my-app-pipe'
 });
 ```
 
 ### Message Patterns
 
 #### 🔥 Fire and Forget
-Fast, one-way messaging when you don't need a response:
+Send messages without waiting for a response:
 
 ```typescript
 // Server
 server.onMessage('log', (data, clientId) => {
-  console.log(`[${clientId}]:`, data.message);
-  // No return value needed
+  console.log(`[${clientId}] ${data.level}:`, data.message);
+  // No return needed
 });
 
 // Client
 await client.sendMessage('log', { 
+  level: 'info',
   message: 'User logged in',
   timestamp: Date.now()
 });
 ```
 
 #### 📞 Request/Response
-RPC-style communication with timeouts and type safety:
+RPC-style communication with type safety:
 
 ```typescript
-// Server - Define your handler with types
-interface CalculateRequest {
-  operation: 'add' | 'multiply';
-  values: number[];
+interface UserRequest {
+  userId: string;
+  fields?: string[];
 }
 
-interface CalculateResponse {
-  result: number;
-  computedAt: number;
+interface UserResponse {
+  id: string;
+  name: string;
+  email?: string;
+  createdAt: number;
 }
 
-server.onMessage<CalculateRequest, CalculateResponse>('calculate', async (data) => {
-  const result = data.operation === 'add' 
-    ? data.values.reduce((a, b) => a + b, 0)
-    : data.values.reduce((a, b) => a * b, 1);
-    
-  return { 
-    result,
-    computedAt: Date.now()
+// Server
+server.onMessage<UserRequest, UserResponse>('getUser', async (data) => {
+  const user = await db.getUser(data.userId);
+  return {
+    id: user.id,
+    name: user.name,
+    email: data.fields?.includes('email') ? user.email : undefined,
+    createdAt: user.createdAt
   };
 });
 
-// Client - Type-safe request
-const response = await client.request<CalculateRequest, CalculateResponse>(
-  'calculate',
-  { operation: 'add', values: [1, 2, 3, 4, 5] },
+// Client - with timeout
+const user = await client.request<UserRequest, UserResponse>(
+  'getUser',
+  { userId: '123', fields: ['email'] },
   { timeout: 5000 }
 );
-
-console.log(`Sum is ${response.result}`);
 ```
 
 #### 📢 Pub/Sub Pattern
 Topic-based message broadcasting:
 
 ```typescript
-// Server automatically handles subscriptions
-const publisher = SmartIpc.createClient({
-  id: 'events-service',
-  clientId: 'publisher'
-});
-
+// Subscribers
 const subscriber1 = SmartIpc.createClient({
   id: 'events-service',
-  clientId: 'subscriber-1'
+  socketPath: '/tmp/events.sock'
 });
 
-const subscriber2 = SmartIpc.createClient({
-  id: 'events-service',
-  clientId: 'subscriber-2'
-});
-
-// Subscribe to topics
+await subscriber1.connect();
 await subscriber1.subscribe('user.login', (data) => {
   console.log('User logged in:', data);
 });
 
-await subscriber2.subscribe('user.*', (data) => {
-  console.log('User event:', data);
+// Publisher
+const publisher = SmartIpc.createClient({
+  id: 'events-service',
+  socketPath: '/tmp/events.sock'
 });
 
-// Publish events
+await publisher.connect();
 await publisher.publish('user.login', { 
   userId: '123',
+  ip: '192.168.1.1',
   timestamp: Date.now()
 });
 ```
 
-## Advanced Features
+## 💪 Advanced Features
 
-### 🔄 Auto-Reconnection with Exponential Backoff
+### 🏁 Server Readiness Detection
 
-Clients automatically reconnect on connection loss:
+Eliminate race conditions in tests and production:
+
+```typescript
+const server = SmartIpc.createServer({
+  id: 'my-service',
+  socketPath: '/tmp/my-service.sock',
+  autoCleanupSocketFile: true
+});
+
+// Option 1: Wait for full readiness
+await server.start({ readyWhen: 'accepting' });
+// Server is now FULLY ready to accept connections
+
+// Option 2: Use ready event
+server.on('ready', () => {
+  console.log('Server is ready!');
+  startClients();
+});
+
+await server.start();
+
+// Option 3: Check readiness state
+if (server.getIsReady()) {
+  console.log('Ready to rock! 🎸');
+}
+```
+
+### 🔄 Smart Connection Retry
+
+Never lose messages due to temporary connection issues:
 
 ```typescript
 const client = SmartIpc.createClient({
-  id: 'resilient-service',
-  clientId: 'auto-reconnect-client',
-  reconnect: {
+  id: 'resilient-client',
+  socketPath: '/tmp/service.sock',
+  connectRetry: {
     enabled: true,
-    initialDelay: 1000,      // Start with 1 second
-    maxDelay: 30000,         // Cap at 30 seconds
-    factor: 2,               // Double each time
-    maxAttempts: Infinity    // Keep trying forever
-  }
+    initialDelay: 100,      // Start with 100ms
+    maxDelay: 1500,         // Cap at 1.5 seconds
+    maxAttempts: 20,        // Try 20 times
+    totalTimeout: 15000     // Give up after 15 seconds total
+  },
+  registerTimeoutMs: 8000   // Registration handshake timeout
 });
 
-// Monitor connection state
-client.on('connected', () => console.log('Connected! 🟢'));
-client.on('disconnected', () => console.log('Connection lost! 🔴'));
-client.on('reconnecting', (attempt) => console.log(`Reconnecting... Attempt ${attempt} 🟡`));
+// Will retry automatically if server isn't ready yet
+await client.connect({ 
+  waitForReady: true,       // Wait for server to exist
+  waitTimeout: 10000        // Wait up to 10 seconds
+});
 ```
 
-### 💓 Heartbeat Monitoring
+### 🛑 Client-Only Mode (No Auto-Start)
 
-Keep connections alive and detect failures quickly:
+In some setups (CLI + long-running daemon), you want clients to fail fast when no server is available, rather than implicitly becoming the server. Enable client-only mode to prevent the “client becomes server” fallback for Unix domain sockets and Windows named pipes.
+
+```typescript
+// Strict client that never auto-starts a server on connect failure
+const client = SmartIpc.createClient({
+  id: 'my-service',
+  socketPath: '/tmp/my-service.sock',
+  clientId: 'my-cli',
+  clientOnly: true,                 // NEW: disable auto-start fallback
+  connectRetry: { enabled: false }  // optional: fail fast
+});
+
+try {
+  await client.connect();
+} catch (err) {
+  // With clientOnly: true, errors become descriptive
+  // e.g. "Server not available (ENOENT); clientOnly prevents auto-start"
+  console.error(err.message);
+}
+```
+
+- Default: `clientOnly` is `false` to preserve backward compatibility.
+- Env override: set `SMARTIPC_CLIENT_ONLY=1` to enforce client-only behavior without code changes.
+- Note: `SmartIpc.waitForServer()` internally uses `clientOnly: true` for safe probing.
+
+### 💓 Graceful Heartbeat Monitoring
+
+Keep connections alive without crashing on timeouts:
 
 ```typescript
 const server = SmartIpc.createServer({
   id: 'monitored-service',
-  heartbeat: {
-    enabled: true,
-    interval: 5000,      // Send heartbeat every 5 seconds
-    timeout: 15000       // Consider dead after 15 seconds
-  }
+  socketPath: '/tmp/monitored.sock',
+  heartbeat: true,
+  heartbeatInterval: 3000,
+  heartbeatTimeout: 10000,
+  heartbeatInitialGracePeriodMs: 5000,    // Grace period for startup
+  heartbeatThrowOnTimeout: false           // Emit event instead of throwing
 });
 
-// Clients automatically respond to heartbeats
+server.on('heartbeatTimeout', (clientId) => {
+  console.log(`Client ${clientId} heartbeat timeout - will handle gracefully`);
+});
+
+// Client configuration
 const client = SmartIpc.createClient({
   id: 'monitored-service',
-  clientId: 'heartbeat-client',
-  heartbeat: true  // Enable heartbeat responses
+  socketPath: '/tmp/monitored.sock',
+  heartbeat: true,
+  heartbeatInterval: 3000,
+  heartbeatTimeout: 10000,
+  heartbeatInitialGracePeriodMs: 5000,
+  heartbeatThrowOnTimeout: false
+});
+
+client.on('heartbeatTimeout', () => {
+  console.log('Heartbeat timeout detected, reconnecting...');
+  // Handle reconnection logic
 });
 ```
 
-### 📊 Real-time Metrics & Observability
+### 🧹 Automatic Socket Cleanup
 
-Track performance and connection health:
+Never worry about stale socket files:
 
 ```typescript
-// Server metrics
+const server = SmartIpc.createServer({
+  id: 'clean-service',
+  socketPath: '/tmp/service.sock',
+  autoCleanupSocketFile: true,    // Remove stale socket on start
+  socketMode: 0o600               // Set socket permissions (Unix only)
+});
+
+// Socket file will be cleaned up automatically on start
+await server.start();
+```
+
+### 📊 Real-time Metrics
+
+Monitor your IPC performance:
+
+```typescript
+// Server stats
 const serverStats = server.getStats();
 console.log({
   isRunning: serverStats.isRunning,
   connectedClients: serverStats.connectedClients,
   totalConnections: serverStats.totalConnections,
-  uptime: serverStats.uptime,
   metrics: {
     messagesSent: serverStats.metrics.messagesSent,
     messagesReceived: serverStats.metrics.messagesReceived,
-    bytesSent: serverStats.metrics.bytesSent,
-    bytesReceived: serverStats.metrics.bytesReceived,
     errors: serverStats.metrics.errors
   }
 });
 
-// Client metrics
+// Client stats
 const clientStats = client.getStats();
 console.log({
   connected: clientStats.connected,
   reconnectAttempts: clientStats.reconnectAttempts,
-  lastActivity: clientStats.lastActivity,
   metrics: clientStats.metrics
 });
 
-// Track specific clients on server
-const clientInfo = server.getClientInfo('client-1');
+// Get specific client info
+const clientInfo = server.getClientInfo('client-123');
 console.log({
-  clientId: clientInfo.clientId,
-  metadata: clientInfo.metadata,
-  connectedAt: clientInfo.connectedAt,
-  lastActivity: clientInfo.lastActivity,
-  subscriptions: clientInfo.subscriptions
+  connectedAt: new Date(clientInfo.connectedAt),
+  lastActivity: new Date(clientInfo.lastActivity),
+  metadata: clientInfo.metadata
 });
 ```
 
-### 🛡️ Security & Limits
+### 🎯 Broadcasting
 
-Protect against malicious or misbehaving clients:
-
-```typescript
-const secureServer = SmartIpc.createServer({
-  id: 'secure-service',
-  maxMessageSize: 10 * 1024 * 1024,  // 10MB max message size
-  maxConnections: 100,                // Limit concurrent connections
-  connectionTimeout: 60000,            // Drop idle connections after 1 minute
-  
-  // Authentication (coming soon)
-  auth: {
-    required: true,
-    validator: async (token) => {
-      // Validate auth token
-      return validateToken(token);
-    }
-  }
-});
-
-// Rate limiting per client
-secureServer.use(rateLimitMiddleware({
-  windowMs: 60000,  // 1 minute window
-  max: 100          // 100 requests per window
-}));
-```
-
-### 🎯 Broadcast to Specific Clients
-
-Send targeted messages:
+Send messages to multiple clients:
 
 ```typescript
 // Broadcast to all connected clients
-server.broadcast('system-alert', { 
-  message: 'Maintenance in 5 minutes'
+await server.broadcast('announcement', { 
+  message: 'Server will restart in 5 minutes',
+  severity: 'warning'
 });
 
-// Send to specific client
-server.sendToClient('client-1', 'personal-message', {
-  content: 'This is just for you'
-});
+// Send to specific clients
+await server.broadcastTo(
+  ['client-1', 'client-2'],
+  'private-message',
+  { content: 'This is just for you two' }
+);
 
-// Send to multiple specific clients
-server.sendToClients(['client-1', 'client-2'], 'group-message', {
-  content: 'Group notification'
+// Send to one client
+await server.sendToClient('client-1', 'direct', {
+  data: 'Personal message'
 });
-
-// Get all connected client IDs
-const clients = server.getConnectedClients();
-console.log('Connected clients:', clients);
 ```
 
-## Error Handling
+## 🧪 Testing Utilities
 
-Comprehensive error handling with typed errors:
+SmartIPC includes powerful helpers for testing:
+
+### Wait for Server
 
 ```typescript
-import { IpcError, ConnectionError, TimeoutError } from '@push.rocks/smartipc';
+import { SmartIpc } from '@push.rocks/smartipc';
 
-// Client error handling
+// Start your server in another process
+const serverProcess = spawn('node', ['server.js']);
+
+// Wait for it to be ready
+await SmartIpc.waitForServer({
+  socketPath: '/tmp/test.sock',
+  timeoutMs: 10000
+});
+
+// Now safe to connect clients
+const client = SmartIpc.createClient({
+  id: 'test-client',
+  socketPath: '/tmp/test.sock'
+});
+await client.connect();
+```
+
+### Spawn and Connect
+
+```typescript
+// Helper that spawns a server and connects a client
+const { client, serverProcess } = await SmartIpc.spawnAndConnect({
+  serverScript: './server.js',
+  socketPath: '/tmp/test.sock',
+  clientId: 'test-client',
+  connectRetry: {
+    enabled: true,
+    maxAttempts: 10
+  }
+});
+
+// Use the client
+const response = await client.request('ping', {});
+
+// Cleanup
+await client.disconnect();
+serverProcess.kill();
+```
+
+## 🎭 Event Handling
+
+SmartIPC provides comprehensive event emitters:
+
+```typescript
+// Server events
+server.on('start', () => console.log('Server started'));
+server.on('ready', () => console.log('Server ready for connections'));
+server.on('clientConnect', (clientId, metadata) => {
+  console.log(`Client ${clientId} connected with metadata:`, metadata);
+});
+server.on('clientDisconnect', (clientId) => {
+  console.log(`Client ${clientId} disconnected`);
+});
+server.on('error', (error, clientId) => {
+  console.error(`Error from ${clientId}:`, error);
+});
+
+// Client events  
+client.on('connect', () => console.log('Connected to server'));
+client.on('disconnect', () => console.log('Disconnected from server'));
+client.on('reconnecting', (attempt) => {
+  console.log(`Reconnection attempt ${attempt}`);
+});
 client.on('error', (error) => {
-  if (error instanceof ConnectionError) {
-    console.error('Connection failed:', error.message);
-  } else if (error instanceof TimeoutError) {
-    console.error('Request timed out:', error.message);
+  console.error('Client error:', error);
+});
+client.on('heartbeatTimeout', (error) => {
+  console.warn('Heartbeat timeout:', error);
+});
+```
+
+## 🛡️ Error Handling
+
+Robust error handling with detailed error information:
+
+```typescript
+// Client-side error handling
+try {
+  const response = await client.request('riskyOperation', data, {
+    timeout: 5000
+  });
+} catch (error) {
+  if (error.message.includes('timeout')) {
+    console.error('Request timed out');
+  } else if (error.message.includes('Failed to register')) {
+    console.error('Could not register with server');
   } else {
     console.error('Unknown error:', error);
   }
-});
-
-// Server error handling
-server.on('client-error', (clientId, error) => {
-  console.error(`Client ${clientId} error:`, error);
-  
-  // Optionally disconnect misbehaving clients
-  if (error.code === 'INVALID_MESSAGE') {
-    server.disconnectClient(clientId);
-  }
-});
-
-// Request with error handling
-try {
-  const response = await client.request('risky-operation', data, {
-    timeout: 5000,
-    retries: 3
-  });
-} catch (error) {
-  if (error instanceof TimeoutError) {
-    // Handle timeout
-  } else {
-    // Handle other errors
-  }
 }
-```
 
-## Testing
-
-SmartIPC includes comprehensive testing utilities:
-
-```typescript
-import { createTestServer, createTestClient } from '@push.rocks/smartipc/testing';
-
-describe('My IPC integration', () => {
-  let server, client;
-  
-  beforeEach(async () => {
-    server = await createTestServer();
-    client = await createTestClient(server);
-  });
-  
-  afterEach(async () => {
-    await client.disconnect();
-    await server.stop();
-  });
-  
-  it('should handle messages', async () => {
-    server.onMessage('test', (data) => ({ echo: data }));
-    
-    const response = await client.request('test', { value: 42 });
-    expect(response.echo.value).toBe(42);
-  });
+// Server-side error boundaries
+server.onMessage('process', async (data, clientId) => {
+  try {
+    return await riskyProcessing(data);
+  } catch (error) {
+    console.error(`Processing failed for ${clientId}:`, error);
+    throw error;  // Will be sent back to client as error
+  }
 });
 ```
 
-## Performance Benchmarks
+## 🏗️ Architecture
 
-SmartIPC has been optimized for high throughput and low latency:
-
-| Transport | Messages/sec | Avg Latency | Use Case |
-|-----------|-------------|-------------|----------|
-| Unix Socket | 150,000+ | < 0.1ms | Local high-performance IPC |
-| TCP (localhost) | 100,000+ | < 0.2ms | Local network-capable IPC |
-| TCP (network) | 50,000+ | < 1ms | Distributed systems |
-| Named Pipe | 120,000+ | < 0.15ms | Windows local IPC |
-
-*Benchmarked on modern hardware with 1KB message payloads*
-
-## Architecture
-
-SmartIPC uses a layered architecture for maximum flexibility:
+SmartIPC uses a clean, layered architecture:
 
 ```
 ┌─────────────────────────────────────────┐
-│          Application Layer              │
-│   (Your business logic and handlers)    │
+│          Your Application               │
+│        (Business logic)                 │
 └─────────────────────────────────────────┘
-                    ↕
+                   ↕
 ┌─────────────────────────────────────────┐
-│          IPC Client / Server            │
-│   (High-level API, patterns, routing)   │
+│         IpcServer / IpcClient           │
+│   (High-level API, Message routing)     │
 └─────────────────────────────────────────┘
-                    ↕
+                   ↕
 ┌─────────────────────────────────────────┐
-│            IPC Channel                  │
-│  (Connection management, reconnection,  │
-│   heartbeat, request/response)          │
+│            IpcChannel                   │
+│  (Connection management, Heartbeat,     │
+│   Reconnection, Request/Response)       │
 └─────────────────────────────────────────┘
-                    ↕
+                   ↕
 ┌─────────────────────────────────────────┐
 │          Transport Layer                │
 │  (TCP, Unix Socket, Named Pipe)         │
@@ -435,29 +515,98 @@ SmartIPC uses a layered architecture for maximum flexibility:
 └─────────────────────────────────────────┘
 ```
 
-## Comparison with Alternatives
+## 🎯 Common Use Cases
 
-| Feature | SmartIPC | node-ipc | zeromq | |
-|---------|----------|----------|---------|--|
-| Zero Dependencies | ✅ | ❌ | ❌ | |
-| TypeScript Native | ✅ | ❌ | ❌ | |
-| Auto-Reconnect | ✅ | ⚠️ | ✅ | |
-| Request/Response | ✅ | ⚠️ | ✅ | |
-| Pub/Sub | ✅ | ❌ | ✅ | |
-| Built-in Metrics | ✅ | ❌ | ❌ | |
-| Heartbeat | ✅ | ❌ | ✅ | |
-| Message Size Limits | ✅ | ❌ | ✅ | |
-| Type Safety | ✅ | ❌ | ❌ | |
+### Microservices Communication
+```typescript
+// API Gateway
+const gateway = SmartIpc.createServer({
+  id: 'api-gateway',
+  socketPath: '/tmp/gateway.sock'
+});
 
-## Support
+// User Service
+const userService = SmartIpc.createClient({
+  id: 'api-gateway',
+  socketPath: '/tmp/gateway.sock',
+  clientId: 'user-service'
+});
 
-- 📖 [Documentation](https://code.foss.global/push.rocks/smartipc)
-- 🐛 [Issue Tracker](https://code.foss.global/push.rocks/smartipc/issues)
-- 💬 [Discussions](https://code.foss.global/push.rocks/smartipc/discussions)
+// Order Service  
+const orderService = SmartIpc.createClient({
+  id: 'api-gateway',
+  socketPath: '/tmp/gateway.sock',
+  clientId: 'order-service'
+});
+```
+
+### Worker Process Management
+```typescript
+// Main process
+const server = SmartIpc.createServer({
+  id: 'main',
+  socketPath: '/tmp/workers.sock'
+});
+
+server.onMessage('job-complete', (result, workerId) => {
+  console.log(`Worker ${workerId} completed job:`, result);
+});
+
+// Worker process
+const worker = SmartIpc.createClient({
+  id: 'main',
+  socketPath: '/tmp/workers.sock',
+  clientId: `worker-${process.pid}`
+});
+
+await worker.sendMessage('job-complete', {
+  jobId: '123',
+  result: processedData
+});
+```
+
+### Real-time Event Distribution
+```typescript
+// Event bus
+const eventBus = SmartIpc.createServer({
+  id: 'event-bus',
+  socketPath: '/tmp/events.sock'
+});
+
+// Services subscribe to events
+const analyticsService = SmartIpc.createClient({
+  id: 'event-bus',
+  socketPath: '/tmp/events.sock'
+});
+
+await analyticsService.subscribe('user.*', (event) => {
+  trackEvent(event);
+});
+```
+
+## 📈 Performance
+
+SmartIPC is optimized for high throughput and low latency:
+
+| Transport | Messages/sec | Avg Latency | Use Case |
+|-----------|-------------|-------------|----------|
+| Unix Socket | 150,000+ | < 0.1ms | Local high-performance IPC (Linux/macOS) |
+| Named Pipe | 120,000+ | < 0.15ms | Windows local IPC |
+| TCP (localhost) | 100,000+ | < 0.2ms | Local network-capable IPC |
+| TCP (network) | 50,000+ | < 1ms | Distributed systems |
+
+- **Memory efficient**: Streaming support for large payloads
+- **CPU efficient**: Event-driven, non-blocking I/O
+
+## 🔧 Requirements
+
+- Node.js >= 14.x
+- TypeScript >= 4.x (for development)
+- Unix-like OS (Linux, macOS) or Windows
 
 ## License and Legal Information
 
-This repository contains open-source code that is licensed under the MIT License. A copy of the MIT License can be found in the [license](license) file within this repository.
+This repository contains open-source code that is licensed under the MIT License. A copy of the MIT License can be found in the [license](license) file within this repository. 
 
 **Please note:** The MIT License does not grant permission to use the trade names, trademarks, service marks, or product names of the project, except as required for reasonable and customary use in describing the origin of the work and reproducing the content of the NOTICE file.
 
@@ -473,7 +622,3 @@ Registered at District court Bremen HRB 35230 HB, Germany
 For any legal inquiries or if you require further information, please contact us via email at hello@task.vc.
 
 By using this repository, you acknowledge that you have read this section, agree to comply with its terms, and understand that the licensing of the code does not imply endorsement by Task Venture Capital GmbH of any derivative works.
-
----
-
-**Built with ❤️ by Task Venture Capital GmbH**

test/test.improvements.ts

@@ -192,6 +192,61 @@ tap.test('Client retry should work with delayed server', async () => {
   await server.stop();
 });
 
+// Test 7: clientOnly prevents client from auto-starting a server
+tap.test('clientOnly should prevent auto-start and fail fast', async () => {
+  const uniqueSocketPath = path.join(os.tmpdir(), `smartipc-clientonly-${Date.now()}.sock`);
+
+  const client = smartipc.SmartIpc.createClient({
+    id: 'clientonly-test',
+    socketPath: uniqueSocketPath,
+    clientId: 'co-client-1',
+    clientOnly: true,
+    connectRetry: { enabled: false }
+  });
+
+  let failed = false;
+  try {
+    await client.connect();
+  } catch (err: any) {
+    failed = true;
+    expect(err.message).toContain('clientOnly prevents auto-start');
+  }
+  expect(failed).toBeTrue();
+  // Ensure no server-side socket was created
+  expect(fs.existsSync(uniqueSocketPath)).toBeFalse();
+});
+
+// Test 8: env SMARTIPC_CLIENT_ONLY enforces clientOnly behavior
+tap.test('SMARTIPC_CLIENT_ONLY=1 should enforce clientOnly', async () => {
+  const uniqueSocketPath = path.join(os.tmpdir(), `smartipc-clientonly-env-${Date.now()}.sock`);
+  const prev = process.env.SMARTIPC_CLIENT_ONLY;
+  process.env.SMARTIPC_CLIENT_ONLY = '1';
+
+  const client = smartipc.SmartIpc.createClient({
+    id: 'clientonly-test-env',
+    socketPath: uniqueSocketPath,
+    clientId: 'co-client-2',
+    connectRetry: { enabled: false }
+  });
+
+  let failed = false;
+  try {
+    await client.connect();
+  } catch (err: any) {
+    failed = true;
+    expect(err.message).toContain('clientOnly prevents auto-start');
+  }
+  expect(failed).toBeTrue();
+  expect(fs.existsSync(uniqueSocketPath)).toBeFalse();
+
+  // restore env
+  if (prev === undefined) {
+    delete process.env.SMARTIPC_CLIENT_ONLY;
+  } else {
+    process.env.SMARTIPC_CLIENT_ONLY = prev;
+  }
+});
+
 // Cleanup
 tap.test('Cleanup test socket', async () => {
   try {
@@ -201,4 +256,4 @@ tap.test('Cleanup test socket', async () => {
   }
 });
 
-export default tap.start();
+export default tap.start();

test/test.ts

@@ -2,6 +2,10 @@ import { expect, tap } from '@git.zone/tstest/tapbundle';
 import * as smartipc from '../ts/index.js';
 import * as smartdelay from '@push.rocks/smartdelay';
 import * as smartpromise from '@push.rocks/smartpromise';
+import * as path from 'path';
+import * as os from 'os';
+
+const testSocketPath = path.join(os.tmpdir(), `test-smartipc-${Date.now()}.sock`);
 
 let server: smartipc.IpcServer;
 let client1: smartipc.IpcClient;
@@ -11,12 +15,13 @@ let client2: smartipc.IpcClient;
 tap.test('should create and start an IPC server', async () => {
   server = smartipc.SmartIpc.createServer({
     id: 'test-server',
-    socketPath: '/tmp/test-smartipc.sock',
+    socketPath: testSocketPath,
+    autoCleanupSocketFile: true,
     heartbeat: true,
     heartbeatInterval: 2000
   });
 
-  await server.start();
+  await server.start({ readyWhen: 'accepting' });
   expect(server.getStats().isRunning).toBeTrue();
 });
 
@@ -24,11 +29,12 @@ tap.test('should create and start an IPC server', async () => {
 tap.test('should create and connect a client', async () => {
   client1 = smartipc.SmartIpc.createClient({
     id: 'test-server',
-    socketPath: '/tmp/test-smartipc.sock',
+    socketPath: testSocketPath,
     clientId: 'client-1',
     metadata: { name: 'Test Client 1' },
     autoReconnect: true,
-    heartbeat: true
+    heartbeat: true,
+    clientOnly: true
   });
 
   await client1.connect();
@@ -76,9 +82,10 @@ tap.test('should handle request/response pattern', async () => {
 tap.test('should handle multiple clients', async () => {
   client2 = smartipc.SmartIpc.createClient({
     id: 'test-server',
-    socketPath: '/tmp/test-smartipc.sock',
+    socketPath: testSocketPath,
     clientId: 'client-2',
-    metadata: { name: 'Test Client 2' }
+    metadata: { name: 'Test Client 2' },
+    clientOnly: true
   });
 
   await client2.connect();
@@ -154,17 +161,6 @@ tap.test('should handle pub/sub pattern', async () => {
     messageReceived.resolve();
   });
 
-  // Server handles the subscription
-  server.onMessage('__subscribe__', async (payload, clientId) => {
-    expect(payload.topic).toEqual('news');
-  });
-
-  // Server handles publishing
-  server.onMessage('__publish__', async (payload, clientId) => {
-    // Broadcast to all subscribers of the topic
-    await server.broadcast(`topic:${payload.topic}`, payload.payload);
-  });
-
   // Client 2 publishes to the topic
   await client2.publish('news', { headline: 'Breaking news!' });
 
@@ -296,4 +292,4 @@ tap.test('should cleanup and close all connections', async () => {
   expect(client1.getIsConnected()).toBeFalse();
 });
 
-export default tap.start();
+export default tap.start();

ts/00_commitinfo_data.ts

@@ -3,6 +3,6 @@
  */
 export const commitinfo = {
   name: '@push.rocks/smartipc',
-  version: '2.1.0',
+  version: '2.2.1',
   description: 'A library for node inter process communication, providing an easy-to-use API for IPC.'
 }

ts/classes.ipcchannel.ts

@@ -49,6 +49,7 @@ export class IpcChannel<TRequest = any, TResponse = any> extends plugins.EventEm
   private reconnectTimer?: NodeJS.Timeout;
   private heartbeatTimer?: NodeJS.Timeout;
   private heartbeatCheckTimer?: NodeJS.Timeout;
+  private heartbeatGraceTimer?: NodeJS.Timeout;
   private lastHeartbeat: number = Date.now();
   private connectionStartTime: number = Date.now();
   private isReconnecting = false;
@@ -81,6 +82,18 @@ export class IpcChannel<TRequest = any, TResponse = any> extends plugins.EventEm
       ...options
     };
 
+    // Normalize heartbeatThrowOnTimeout to boolean (defensive for JS consumers)
+    const throwOnTimeout = (this.options as any).heartbeatThrowOnTimeout;
+    if (throwOnTimeout !== undefined) {
+      if (throwOnTimeout === 'false') {
+        this.options.heartbeatThrowOnTimeout = false;
+      } else if (throwOnTimeout === 'true') {
+        this.options.heartbeatThrowOnTimeout = true;
+      } else if (typeof throwOnTimeout !== 'boolean') {
+        this.options.heartbeatThrowOnTimeout = Boolean(throwOnTimeout);
+      }
+    }
+
     this.transport = createTransport(this.options);
     this.setupTransportHandlers();
   }
@@ -217,16 +230,27 @@ export class IpcChannel<TRequest = any, TResponse = any> extends plugins.EventEm
       });
     }, this.options.heartbeatInterval!);
 
+    // Delay starting the check until after the grace period
+    const gracePeriod = this.options.heartbeatInitialGracePeriodMs || 0;
+    
+    if (gracePeriod > 0) {
+      // Use a timer to delay the first check
+      this.heartbeatGraceTimer = setTimeout(() => {
+        this.startHeartbeatCheck();
+      }, gracePeriod);
+    } else {
+      // No grace period, start checking immediately
+      this.startHeartbeatCheck();
+    }
+  }
+
+  /**
+   * Start heartbeat timeout checking (separated for grace period handling)
+   */
+  private startHeartbeatCheck(): void {
     // Check for heartbeat timeout
     this.heartbeatCheckTimer = setInterval(() => {
       const timeSinceLastHeartbeat = Date.now() - this.lastHeartbeat;
-      const timeSinceConnection = Date.now() - this.connectionStartTime;
-      const gracePeriod = this.options.heartbeatInitialGracePeriodMs || 0;
-      
-      // Skip timeout check during initial grace period
-      if (timeSinceConnection < gracePeriod) {
-        return;
-      }
       
       if (timeSinceLastHeartbeat > this.options.heartbeatTimeout!) {
         const error = new Error('Heartbeat timeout');
@@ -238,9 +262,11 @@ export class IpcChannel<TRequest = any, TResponse = any> extends plugins.EventEm
         } else {
           // Emit heartbeatTimeout event instead of error
           this.emit('heartbeatTimeout', error);
+          // Clear timers to avoid repeated events
+          this.stopHeartbeat();
         }
       }
-    }, this.options.heartbeatTimeout! / 2);
+    }, Math.max(1000, Math.floor(this.options.heartbeatTimeout! / 2)));
   }
 
   /**
@@ -256,6 +282,11 @@ export class IpcChannel<TRequest = any, TResponse = any> extends plugins.EventEm
       clearInterval(this.heartbeatCheckTimer);
       this.heartbeatCheckTimer = undefined;
     }
+
+    if (this.heartbeatGraceTimer) {
+      clearTimeout(this.heartbeatGraceTimer);
+      this.heartbeatGraceTimer = undefined;
+    }
   }
 
   /**
@@ -430,7 +461,7 @@ export class IpcChannel<TRequest = any, TResponse = any> extends plugins.EventEm
    * Register a message handler
    */
   public on(event: string, handler: (payload: any) => any | Promise<any>): this {
-    if (event === 'message' || event === 'connect' || event === 'disconnect' || event === 'error' || event === 'reconnecting' || event === 'drain') {
+    if (event === 'message' || event === 'connect' || event === 'disconnect' || event === 'error' || event === 'reconnecting' || event === 'drain' || event === 'heartbeatTimeout') {
       // Special handling for channel events
       super.on(event, handler);
     } else {

ts/classes.ipcclient.ts

@@ -45,6 +45,7 @@ export class IpcClient extends plugins.EventEmitter {
   private messageHandlers = new Map<string, (payload: any) => any | Promise<any>>();
   private isConnected = false;
   private clientId: string;
+  private didRegisterOnce = false;
 
   constructor(options: IIpcClientOptions) {
     super();
@@ -66,27 +67,7 @@ export class IpcClient extends plugins.EventEmitter {
 
     // Helper function to attempt registration
     const attemptRegistration = async (): Promise<void> => {
-      const registerTimeoutMs = this.options.registerTimeoutMs || 5000;
-      
-      try {
-        const response = await this.channel.request<any, any>(
-          '__register__',
-          {
-            clientId: this.clientId,
-            metadata: this.options.metadata
-          },
-          { timeout: registerTimeoutMs }
-        );
-
-        if (!response.success) {
-          throw new Error(response.error || 'Registration failed');
-        }
-
-        this.isConnected = true;
-        this.emit('connect');
-      } catch (error) {
-        throw new Error(`Failed to register with server: ${error.message}`);
-      }
+      await this.attemptRegistrationInternal();
     };
 
     // Helper function to attempt connection with retry
@@ -167,6 +148,38 @@ export class IpcClient extends plugins.EventEmitter {
     }
   }
 
+  /**
+   * Attempt to register this client over the current channel connection.
+   * Sets connection flags and emits 'connect' on success.
+   */
+  private async attemptRegistrationInternal(): Promise<void> {
+    const registerTimeoutMs = this.options.registerTimeoutMs || 5000;
+
+    try {
+      const response = await this.channel.request<any, any>(
+        '__register__',
+        {
+          clientId: this.clientId,
+          metadata: this.options.metadata
+        },
+        {
+          timeout: registerTimeoutMs,
+          headers: { clientId: this.clientId }
+        }
+      );
+
+      if (!response.success) {
+        throw new Error(response.error || 'Registration failed');
+      }
+
+      this.isConnected = true;
+      this.didRegisterOnce = true;
+      this.emit('connect');
+    } catch (error: any) {
+      throw new Error(`Failed to register with server: ${error.message}`);
+    }
+  }
+
   /**
    * Disconnect from the server
    */
@@ -185,8 +198,16 @@ export class IpcClient extends plugins.EventEmitter {
    */
   private setupChannelHandlers(): void {
     // Forward channel events
-    this.channel.on('connect', () => {
-      // Don't emit connect here, wait for successful registration
+    this.channel.on('connect', async () => {
+      // On reconnects, re-register automatically when we had connected before
+      if (this.didRegisterOnce && !this.isConnected) {
+        try {
+          await this.attemptRegistrationInternal();
+        } catch (error) {
+          this.emit('error', error);
+        }
+      }
+      // For initial connect(), registration is handled explicitly there
     });
 
     this.channel.on('disconnect', (reason) => {
@@ -194,10 +215,20 @@ export class IpcClient extends plugins.EventEmitter {
       this.emit('disconnect', reason);
     });
 
-    this.channel.on('error', (error) => {
+    this.channel.on('error', (error: any) => {
+      // If heartbeat timeout and configured not to throw, convert to heartbeatTimeout event
+      if (error && error.message === 'Heartbeat timeout' && this.options.heartbeatThrowOnTimeout === false) {
+        this.emit('heartbeatTimeout', error);
+        return;
+      }
       this.emit('error', error);
     });
 
+    this.channel.on('heartbeatTimeout', (error) => {
+      // Forward heartbeatTimeout event (when heartbeatThrowOnTimeout is false)
+      this.emit('heartbeatTimeout', error);
+    });
+
     this.channel.on('reconnecting', (info) => {
       this.emit('reconnecting', info);
     });
@@ -330,4 +361,4 @@ export class IpcClient extends plugins.EventEmitter {
   public getStats(): any {
     return this.channel.getStats();
   }
-}
+}

ts/classes.ipcserver.ts

@@ -200,6 +200,11 @@ export class IpcServer extends plugins.EventEmitter {
       this.emit('error', error, 'server');
     });
 
+    this.primaryChannel.on('heartbeatTimeout', (error) => {
+      // Forward heartbeatTimeout event (when heartbeatThrowOnTimeout is false)
+      this.emit('heartbeatTimeout', error, 'server');
+    });
+
     // Connect the primary channel (will start as server)
     await this.primaryChannel.connect();
     
@@ -339,6 +344,19 @@ export class IpcServer extends plugins.EventEmitter {
       }
       this.emit('error', error, actualClientId);
     });
+
+    channel.on('heartbeatTimeout', (error) => {
+      // Find the actual client ID for this channel
+      let actualClientId = clientId;
+      for (const [id, client] of this.clients) {
+        if (client.channel === channel) {
+          actualClientId = id;
+          break;
+        }
+      }
+      // Forward heartbeatTimeout event (when heartbeatThrowOnTimeout is false)
+      this.emit('heartbeatTimeout', error, actualClientId);
+    });
   }
 
   /**

ts/classes.transports.ts

@@ -18,6 +18,12 @@ export interface IIpcMessageEnvelope<T = any> {
 export interface IIpcTransportOptions {
   /** Unique identifier for this transport */
   id: string;
+  /**
+   * When true, a client transport will NOT auto-start a server when connect()
+   * encounters ECONNREFUSED/ENOENT. Useful for strict client/daemon setups.
+   * Default: false. Can also be overridden by env SMARTIPC_CLIENT_ONLY=1.
+   */
+  clientOnly?: boolean;
   /** Socket path for Unix domain sockets or pipe name for Windows */
   socketPath?: string;
   /** TCP host for network transport */
@@ -169,6 +175,8 @@ export class UnixSocketTransport extends IpcTransport {
   private socket: plugins.net.Socket | null = null;
   private server: plugins.net.Server | null = null;
   private clients: Set<plugins.net.Socket> = new Set();
+  private socketToClientId = new WeakMap<plugins.net.Socket, string>();
+  private clientIdToSocket = new Map<string, plugins.net.Socket>();
 
   /**
    * Connect as client or start as server
@@ -193,7 +201,21 @@ export class UnixSocketTransport extends IpcTransport {
 
       this.socket.on('error', (error: any) => {
         if (error.code === 'ECONNREFUSED' || error.code === 'ENOENT') {
-          // No server exists, we should become the server
+          // Determine if we must NOT auto-start server
+          const envVal = process.env.SMARTIPC_CLIENT_ONLY;
+          const envClientOnly = !!envVal && (envVal === '1' || envVal === 'true' || envVal === 'TRUE');
+          const clientOnly = this.options.clientOnly === true || envClientOnly;
+
+          if (clientOnly) {
+            // Reject instead of starting a server to avoid races
+            const reason = error.code || 'UNKNOWN';
+            const err = new Error(`Server not available (${reason}); clientOnly prevents auto-start`);
+            (err as any).code = reason;
+            reject(err);
+            return;
+          }
+
+          // No server exists and clientOnly is false: become the server (back-compat)
           this.socket = null;
           this.startServer(socketPath).then(resolve).catch(reject);
         } else {
@@ -239,6 +261,12 @@ export class UnixSocketTransport extends IpcTransport {
 
         socket.on('close', () => {
           this.clients.delete(socket);
+          // Clean up clientId mappings
+          const clientId = this.socketToClientId.get(socket);
+          if (clientId && this.clientIdToSocket.get(clientId) === socket) {
+            this.clientIdToSocket.delete(clientId);
+          }
+          this.socketToClientId.delete(socket);
           this.emit('clientDisconnected', socket);
         });
 
@@ -307,7 +335,18 @@ export class UnixSocketTransport extends IpcTransport {
           // Parse and emit the message with socket reference
           try {
             const message = JSON.parse(messageData.toString('utf8')) as IIpcMessageEnvelope;
+            
+            // Update clientId mapping
+            const clientId = message.headers?.clientId ?? 
+              (message.type === '__register__' ? (message.payload as any)?.clientId : undefined);
+            if (clientId) {
+              this.socketToClientId.set(socket, clientId);
+              this.clientIdToSocket.set(clientId, socket);
+            }
+            
+            // Emit both events so IpcChannel can process it
             this.emit('clientMessage', message, socket);
+            this.emit('message', message);
           } catch (error: any) {
             this.emit('error', new Error(`Failed to parse message: ${error.message}`));
           }
@@ -415,27 +454,54 @@ export class UnixSocketTransport extends IpcTransport {
         }
       });
     } else if (this.server && this.clients.size > 0) {
-      // Server mode - broadcast to all clients
-      const promises: Promise<boolean>[] = [];
+      // Server mode - route by clientId if present, otherwise broadcast
+      const targetClientId = message.headers?.clientId;
       
-      for (const client of this.clients) {
-        promises.push(new Promise((resolve) => {
-          const success = client.write(frame, (error) => {
-            if (error) {
-              resolve(false);
-            } else {
-              resolve(true);
+      if (targetClientId && this.clientIdToSocket.has(targetClientId)) {
+        // Send to specific client
+        const targetSocket = this.clientIdToSocket.get(targetClientId)!;
+        if (targetSocket && !targetSocket.destroyed) {
+          return new Promise((resolve) => {
+            const success = targetSocket.write(frame, (error) => {
+              if (error) {
+                resolve(false);
+              } else {
+                resolve(true);
+              }
+            });
+
+            if (!success) {
+              targetSocket.once('drain', () => resolve(true));
             }
           });
+        } else {
+          // Socket is destroyed, remove from mappings
+          this.clientIdToSocket.delete(targetClientId);
+          return false;
+        }
+      } else {
+        // Broadcast to all clients (fallback for messages without specific target)
+        const promises: Promise<boolean>[] = [];
+        
+        for (const client of this.clients) {
+          promises.push(new Promise((resolve) => {
+            const success = client.write(frame, (error) => {
+              if (error) {
+                resolve(false);
+              } else {
+                resolve(true);
+              }
+            });
 
-          if (!success) {
-            client.once('drain', () => resolve(true));
-          }
-        }));
+            if (!success) {
+              client.once('drain', () => resolve(true));
+            }
+          }));
+        }
+
+        const results = await Promise.all(promises);
+        return results.every(r => r);
       }
-
-      const results = await Promise.all(promises);
-      return results.every(r => r);
     }
 
     return false;
@@ -672,4 +738,4 @@ export function createTransport(options: IIpcTransportOptions): IpcTransport {
   } else {
     return new UnixSocketTransport(options);
   }
-}
+}

ts/index.ts

@@ -29,20 +29,28 @@ export class SmartIpc {
     
     while (Date.now() - startTime < timeout) {
       try {
-        // Try to connect as a temporary client
-        const testClient = new IpcClient({
-          id: `test-probe-${Date.now()}`,
+        // Create a temporary client with proper options
+        const testClient = SmartIpc.createClient({
+          id: 'test-probe',
           socketPath: options.socketPath,
-          autoReconnect: false,
-          heartbeat: false
+          clientId: `probe-${process.pid}-${Date.now()}`,
+          heartbeat: false,
+          clientOnly: true,
+          connectRetry: {
+            enabled: false  // Don't retry, we're handling retries here
+          },
+          registerTimeoutMs: 2000  // Short timeout for quick probing
         });
         
+        // Try to connect and register with the server
         await testClient.connect();
+        
+        // Success! Clean up and return
         await testClient.disconnect();
-        return; // Server is ready
+        return;
       } catch (error) {
         // Server not ready yet, wait and retry
-        await new Promise(resolve => setTimeout(resolve, 100));
+        await new Promise(resolve => setTimeout(resolve, 200));
       }
     }
     
@@ -120,4 +128,4 @@ export class SmartIpc {
 }
 
 // Export the main class as default
-export default SmartIpc;
+export default SmartIpc;