diff --git a/claude-code-extension/src/lib.rs b/claude-code-extension/src/lib.rs
index 7044084..0811fc6 100644
--- a/claude-code-extension/src/lib.rs
+++ b/claude-code-extension/src/lib.rs
@@ -88,7 +88,7 @@ impl Extension for ClaudeCodeExtension {
                         "debug": true,
                         "websocket": {
                             "host": "127.0.0.1",
-                            "portRange": [10000, 65535]
+                            "portRange": [59790, 59799]
                         },
                         "auth": {
                             "generateTokens": true
diff --git a/claude-code-server/src/main.rs b/claude-code-server/src/main.rs
index 8c2b8d6..ed8ac44 100644
--- a/claude-code-server/src/main.rs
+++ b/claude-code-server/src/main.rs
@@ -36,13 +36,13 @@ enum Mode {
     },
     /// Run as standalone WebSocket server for Claude Code CLI
     Websocket {
-        /// WebSocket server port (default: 59791)
+        /// WebSocket server port (default: auto-select from 59790-59799)
         #[arg(long, short)]
         port: Option<u16>,
     },
     /// Run both LSP and WebSocket servers
     Hybrid {
-        /// WebSocket server port (default: 59791)
+        /// WebSocket server port (default: auto-select from 59790-59799)
         #[arg(long, short)]
         port: Option<u16>,
         /// Worktree root path
diff --git a/claude-code-server/src/websocket.rs b/claude-code-server/src/websocket.rs
index ec61449..534cfb8 100644
--- a/claude-code-server/src/websocket.rs
+++ b/claude-code-server/src/websocket.rs
@@ -51,48 +51,47 @@ pub async fn run_websocket_server_with_notifications(
 ) -> Result<()> {
     info!("Starting WebSocket server...");
 
-    // Use fixed port or provided port, default to 59792
-    let port = port.unwrap_or(59792);
-
-    // Clean up any existing lock files for this port
-    cleanup_existing_lock_file(port).await?;
-
-    // Create new lock file
-    let auth_token = Uuid::new_v4().to_string();
-    create_lock_file(port, worktree.clone(), &auth_token).await?;
-
-    // Start WebSocket server with proper error handling
-    let addr = format!("127.0.0.1:{}", port);
-
-    // Try to bind to the port, with retry logic
-    let listener = match TcpListener::bind(&addr).await {
-        Ok(listener) => {
-            info!("WebSocket server listening on {}", addr);
-            listener
-        }
-        Err(e) => {
-            error!("Failed to bind to port {}: {}", port, e);
-            info!("Attempting to force cleanup and retry...");
-
-            // Try to cleanup and retry once
-            cleanup_existing_lock_file(port).await?;
-
-            // Wait a moment for the port to be released
-            tokio::time::sleep(tokio::time::Duration::from_millis(500)).await;
-
+    // Port range for multi-instance support (59790-59799, max 10 instances)
+    const PORT_RANGE_START: u16 = 59790;
+    const PORT_RANGE_END: u16 = 59799;
+
+    let (listener, port) = if let Some(port) = port {
+        // Explicit port requested - use it directly
+        let addr = format!("127.0.0.1:{}", port);
+        let listener = TcpListener::bind(&addr)
+            .await
+            .map_err(|e| anyhow!("Failed to bind to requested port {}: {}", port, e))?;
+        info!("WebSocket server listening on {}", addr);
+        (listener, port)
+    } else {
+        // No port specified - find first available port in range
+        let mut bound = None;
+        for p in PORT_RANGE_START..=PORT_RANGE_END {
+            let addr = format!("127.0.0.1:{}", p);
             match TcpListener::bind(&addr).await {
                 Ok(listener) => {
-                    info!("Successfully bound to port {} after cleanup", port);
-                    listener
+                    info!("WebSocket server listening on {} (auto-selected)", addr);
+                    bound = Some((listener, p));
+                    break;
                 }
-                Err(e2) => {
-                    error!("Failed to bind to port {} even after cleanup: {}", port, e2);
-                    return Err(anyhow!("Port {} is unavailable: {}", port, e2));
+                Err(_) => {
+                    info!("Port {} in use, trying next...", p);
                 }
             }
         }
+        bound.ok_or_else(|| {
+            anyhow!(
+                "No available port in range {}-{} (max 10 instances)",
+                PORT_RANGE_START,
+                PORT_RANGE_END
+            )
+        })?
     };
 
+    // Create new lock file
+    let auth_token = Uuid::new_v4().to_string();
+    create_lock_file(port, worktree.clone(), &auth_token).await?;
+
     // Setup graceful shutdown handler
     let port_for_cleanup = port;
     tokio::spawn(async move {