fix: improve error messages around --auto-connect (#1075)

Author: OrKoN

README.md

@@ -459,7 +459,7 @@ The Chrome DevTools MCP server supports the following configuration option:
 <!-- BEGIN AUTO GENERATED OPTIONS -->
 
 - **`--autoConnect`/ `--auto-connect`**
-  If specified, automatically connects to a browser (Chrome 144+) running in the user data directory identified by the channel param. Requires the remoted debugging server to be started in the Chrome instance via chrome://inspect/#remote-debugging.
+  If specified, automatically connects to a browser (Chrome 144+) running locally from the user data directory identified by the channel param (default channel is stable). Requires the remoted debugging server to be started in the Chrome instance via chrome://inspect/#remote-debugging.
   - **Type:** boolean
   - **Default:** `false`
 

src/browser.ts

@@ -63,6 +63,7 @@ export async function ensureBrowserConnected(options: {
     handleDevToolsAsPage: true,
   };
 
+  let autoConnect = false;
   if (options.wsEndpoint) {
     connectOptions.browserWSEndpoint = options.wsEndpoint;
     if (options.wsHeaders) {
@@ -73,6 +74,7 @@ export async function ensureBrowserConnected(options: {
   } else if (channel || options.userDataDir) {
     const userDataDir = options.userDataDir;
     if (userDataDir) {
+      autoConnect = true;
       // TODO: re-expose this logic via Puppeteer.
       const portPath = path.join(userDataDir, 'DevToolsActivePort');
       try {
@@ -96,7 +98,7 @@ export async function ensureBrowserConnected(options: {
         connectOptions.browserWSEndpoint = browserWSEndpoint;
       } catch (error) {
         throw new Error(
-          `Could not connect to Chrome in ${userDataDir}. Check if Chrome is running and remote debugging is enabled.`,
+          `Could not connect to Chrome in ${userDataDir}. Check if Chrome is running and remote debugging is enabled by going to chrome://inspect/#remote-debugging.`,
           {
             cause: error,
           },
@@ -121,7 +123,7 @@ export async function ensureBrowserConnected(options: {
     browser = await puppeteer.connect(connectOptions);
   } catch (err) {
     throw new Error(
-      'Could not connect to Chrome. Check if Chrome is running and remote debugging is enabled by going to chrome://inspect/#remote-debugging.',
+      `Could not connect to Chrome. ${autoConnect ? `Check if Chrome is running and remote debugging is enabled by going to chrome://inspect/#remote-debugging.` : `Check if Chrome is running.`}`,
       {
         cause: err,
       },

src/cli.ts

@@ -11,7 +11,7 @@ export const cliOptions = {
   autoConnect: {
     type: 'boolean',
     description:
-      'If specified, automatically connects to a browser (Chrome 144+) running in the user data directory identified by the channel param. Requires the remoted debugging server to be started in the Chrome instance via chrome://inspect/#remote-debugging.',
+      'If specified, automatically connects to a browser (Chrome 144+) running locally from the user data directory identified by the channel param (default channel is stable). Requires the remoted debugging server to be started in the Chrome instance via chrome://inspect/#remote-debugging.',
     conflicts: ['isolated', 'executablePath'],
     default: false,
     coerce: (value: boolean | undefined) => {