diff --git a/README.md b/README.md
index bac5231..75bae5b 100644
--- a/README.md
+++ b/README.md
@@ -93,6 +93,30 @@ await browser.close()
 server.close()
 ```
 
+### Environment Variables
+
+#### `PLAYWRITER_AUTO_ENABLE`
+
+When set, the MCP will automatically create an initial tab when a Playwright client connects and no tabs are currently enabled. This is useful for fully automated workflows where you don't want to manually click the extension icon.
+
+```json
+{
+  "mcpServers": {
+    "playwriter": {
+      "command": "npx",
+      "args": ["playwriter@latest"],
+      "env": {
+        "PLAYWRITER_AUTO_ENABLE": "1"
+      }
+    }
+  }
+}
+```
+
+With this setting, when your AI agent starts, it will immediately have a page to work with without requiring manual extension activation.
+
+**Note:** The auto-created tab starts at `about:blank`. Your agent can then navigate it to any URL.
+
 ## Comparison
 
 ### vs Playwright MCP
diff --git a/extension/src/background.ts b/extension/src/background.ts
index 9f2db5d..f71b5da 100644
--- a/extension/src/background.ts
+++ b/extension/src/background.ts
@@ -560,6 +560,21 @@ function handleConnectionClose(reason: string, code: number): void {
 }
 
 async function ensureConnection(): Promise<void> {
+  // If already connecting, wait for that connection to complete instead of creating a new one
+  // This prevents "Extension Replaced" errors when multiple callers race to connect
+  if (ws?.readyState === WebSocket.CONNECTING) {
+    logger.debug('Connection already in progress, waiting for it to complete')
+    const existingWs = ws
+    await new Promise<void>((resolve) => {
+      const checkInterval = setInterval(() => {
+        if (existingWs.readyState !== WebSocket.CONNECTING) {
+          clearInterval(checkInterval)
+          resolve()
+        }
+      }, 100)
+    })
+  }
+
   if (ws?.readyState === WebSocket.OPEN) {
     logger.debug('Connection already exists, reusing')
     return