Add Chrome for Testing support for reliable WebDriver automation

- Add setup script (scripts/setup-chrome-for-testing.sh) that downloads
  matching Chrome and ChromeDriver versions from Google's CDN
- Add chrome_binary config option to specify custom Chrome binary path
- Update ChromeDriver to support custom binary via with_port_headless_and_binary()
- Update README with Chrome for Testing setup instructions
- Update config.example.toml with chrome_binary documentation

Chrome for Testing is Google's dedicated browser for automated testing
that guarantees version compatibility with ChromeDriver, avoiding the
common 'version mismatch' errors when Chrome auto-updates.

README.md

@@ -273,11 +273,25 @@ g3 --webdriver
 g3 --webdriver --safari
 ```
 
-**Chrome Headless Setup**: Install ChromeDriver:
+**Chrome Setup Options**:
+
+*Option 1: Use Chrome for Testing (Recommended)* - Guarantees version compatibility:
+```bash
+./scripts/setup-chrome-for-testing.sh
+```
+Then add to your `~/.config/g3/config.toml`:
+```toml
+[webdriver]
+chrome_binary = "/Users/yourname/.chrome-for-testing/chrome-mac-arm64/Google Chrome for Testing.app/Contents/MacOS/Google Chrome for Testing"
+```
+
+*Option 2: Use system Chrome* - Requires matching ChromeDriver version:
 - macOS: `brew install chromedriver`
 - Linux: `apt install chromium-chromedriver`
 - Or download from: https://chromedriver.chromium.org/downloads
 
+**Note**: If you see "ChromeDriver version doesn't match Chrome version" errors, use Option 1 (Chrome for Testing) which bundles matching versions.
+
 ## macOS Accessibility API Tools
 
 G3 includes support for controlling macOS applications via the Accessibility API, allowing you to automate native macOS apps.

config.example.toml

@@ -110,6 +110,12 @@ chrome_port = 9515
 # Safari opens a visible browser window
 # Chrome headless runs in the background without a visible window
 browser = "chrome-headless"
+# Optional: Path to Chrome binary (e.g., Chrome for Testing)
+# If not set, ChromeDriver will use the default Chrome installation
+# Use this to avoid version mismatch issues between Chrome and ChromeDriver
+# Run: ./scripts/setup-chrome-for-testing.sh to install matching versions
+# chrome_binary = "/Users/yourname/.chrome-for-testing/chrome-mac-arm64/Google Chrome for Testing.app/Contents/MacOS/Google Chrome for Testing"
+# chrome_binary = "/Users/yourname/.chrome-for-testing/chrome-mac-x64/Google Chrome for Testing.app/Contents/MacOS/Google Chrome for Testing"
 
 [macax]
 enabled = false

crates/g3-computer-control/src/webdriver/chrome.rs

@@ -19,8 +19,18 @@ impl ChromeDriver {
         Self::with_port_headless(9515).await
     }
 
+    /// Create a new ChromeDriver instance with Chrome for Testing binary
+    pub async fn new_headless_with_binary(chrome_binary: &str) -> Result<Self> {
+        Self::with_port_headless_and_binary(9515, Some(chrome_binary)).await
+    }
+
     /// Create a new ChromeDriver instance with a custom port in headless mode
     pub async fn with_port_headless(port: u16) -> Result<Self> {
+        Self::with_port_headless_and_binary(port, None).await
+    }
+
+    /// Create a new ChromeDriver instance with a custom port and optional Chrome binary path
+    pub async fn with_port_headless_and_binary(port: u16, chrome_binary: Option<&str>) -> Result<Self> {
         let url = format!("http://localhost:{}", port);
 
         let mut caps = serde_json::Map::new();
@@ -41,6 +51,12 @@ impl ChromeDriver {
                 Value::String("--window-size=1920,1080".to_string()),
             ]),
         );
+
+        // If a custom Chrome binary is specified, use it
+        if let Some(binary) = chrome_binary {
+            chrome_options.insert("binary".to_string(), Value::String(binary.to_string()));
+        }
+
         caps.insert(
             "goog:chromeOptions".to_string(),
             Value::Object(chrome_options),

crates/g3-config/src/lib.rs

@@ -132,6 +132,10 @@ pub struct WebDriverConfig {
     #[serde(default)]
     pub chrome_port: u16,
     #[serde(default)]
+    /// Optional path to Chrome binary (e.g., Chrome for Testing)
+    /// If not set, ChromeDriver will use the default Chrome installation
+    pub chrome_binary: Option<String>,
+    #[serde(default)]
     pub browser: WebDriverBrowser,
 }
 
@@ -152,6 +156,7 @@ impl Default for WebDriverConfig {
             enabled: true,
             safari_port: 4444,
             chrome_port: 9515,
+            chrome_binary: None,
             browser: WebDriverBrowser::ChromeHeadless,
         }
     }

crates/g3-core/src/lib.rs

@@ -5605,8 +5605,13 @@ impl<W: UiWriter> Agent<W> {
                             // Wait before each attempt (200ms between retries, total max ~2s)
                             tokio::time::sleep(tokio::time::Duration::from_millis(200)).await;
                             
-                            // Try to connect to ChromeDriver in headless mode
-                            match g3_computer_control::ChromeDriver::with_port_headless(port).await {
+                            // Try to connect to ChromeDriver in headless mode (with optional custom binary)
+                            let driver_result = match &self.config.webdriver.chrome_binary {
+                                Some(binary) => g3_computer_control::ChromeDriver::with_port_headless_and_binary(port, Some(binary)).await,
+                                None => g3_computer_control::ChromeDriver::with_port_headless(port).await,
+                            };
+                            
+                            match driver_result {
                                 Ok(driver) => {
                                     let session = std::sync::Arc::new(tokio::sync::Mutex::new(WebDriverSession::Chrome(driver)));
                                     *self.webdriver_session.write().await = Some(session);

scripts/setup-chrome-for-testing.sh

@@ -0,0 +1,116 @@
+#!/bin/bash
+# Setup Chrome for Testing with matching ChromeDriver
+# This ensures version compatibility for WebDriver automation
+
+set -e
+
+# Configuration
+INSTALL_DIR="${HOME}/.chrome-for-testing"
+BIN_DIR="${HOME}/.local/bin"
+
+# Detect architecture
+ARCH=$(uname -m)
+if [ "$ARCH" = "arm64" ]; then
+    PLATFORM="mac-arm64"
+elif [ "$ARCH" = "x86_64" ]; then
+    PLATFORM="mac-x64"
+else
+    echo "❌ Unsupported architecture: $ARCH"
+    exit 1
+fi
+
+echo "🔍 Detecting platform: $PLATFORM"
+
+# Get latest stable version info
+echo "📡 Fetching latest Chrome for Testing version..."
+VERSION_JSON=$(curl -s 'https://googlechromelabs.github.io/chrome-for-testing/last-known-good-versions-with-downloads.json')
+VERSION=$(echo "$VERSION_JSON" | python3 -c "import json,sys; print(json.load(sys.stdin)['channels']['Stable']['version'])")
+
+echo "📦 Latest stable version: $VERSION"
+
+# Get download URLs
+CHROME_URL=$(echo "$VERSION_JSON" | python3 -c "
+import json,sys
+data = json.load(sys.stdin)
+for d in data['channels']['Stable']['downloads']['chrome']:
+    if d['platform'] == '$PLATFORM':
+        print(d['url'])
+        break
+")
+
+CHROMEDRIVER_URL=$(echo "$VERSION_JSON" | python3 -c "
+import json,sys
+data = json.load(sys.stdin)
+for d in data['channels']['Stable']['downloads']['chromedriver']:
+    if d['platform'] == '$PLATFORM':
+        print(d['url'])
+        break
+")
+
+# Create directories
+mkdir -p "$INSTALL_DIR"
+mkdir -p "$BIN_DIR"
+
+# Download and extract Chrome for Testing
+echo "⬇️  Downloading Chrome for Testing..."
+cd "$INSTALL_DIR"
+curl -L -o chrome.zip "$CHROME_URL"
+unzip -q -o chrome.zip
+rm chrome.zip
+
+# The extracted folder name varies by platform
+CHROME_APP_DIR="chrome-$PLATFORM"
+if [ -d "$CHROME_APP_DIR" ]; then
+    echo "✅ Chrome for Testing installed to: $INSTALL_DIR/$CHROME_APP_DIR"
+else
+    echo "❌ Chrome extraction failed"
+    exit 1
+fi
+
+# Download and extract ChromeDriver
+echo "⬇️  Downloading ChromeDriver..."
+curl -L -o chromedriver.zip "$CHROMEDRIVER_URL"
+unzip -q -o chromedriver.zip
+rm chromedriver.zip
+
+CHROMEDRIVER_DIR="chromedriver-$PLATFORM"
+if [ -f "$CHROMEDRIVER_DIR/chromedriver" ]; then
+    # Create symlink in bin directory
+    ln -sf "$INSTALL_DIR/$CHROMEDRIVER_DIR/chromedriver" "$BIN_DIR/chromedriver-for-testing"
+    chmod +x "$INSTALL_DIR/$CHROMEDRIVER_DIR/chromedriver"
+    echo "✅ ChromeDriver installed and linked to: $BIN_DIR/chromedriver-for-testing"
+else
+    echo "❌ ChromeDriver extraction failed"
+    exit 1
+fi
+
+# Create a wrapper script that uses Chrome for Testing
+cat > "$BIN_DIR/chrome-for-testing" << 'EOF'
+#!/bin/bash
+INSTALL_DIR="${HOME}/.chrome-for-testing"
+ARCH=$(uname -m)
+if [ "$ARCH" = "arm64" ]; then
+    PLATFORM="mac-arm64"
+else
+    PLATFORM="mac-x64"
+fi
+exec "$INSTALL_DIR/chrome-$PLATFORM/Google Chrome for Testing.app/Contents/MacOS/Google Chrome for Testing" "$@"
+EOF
+chmod +x "$BIN_DIR/chrome-for-testing"
+
+echo ""
+echo "✅ Setup complete!"
+echo ""
+echo "Installed versions:"
+echo "  Chrome for Testing: $VERSION"
+echo "  ChromeDriver: $VERSION"
+echo ""
+echo "Binaries:"
+echo "  Chrome: $BIN_DIR/chrome-for-testing"
+echo "  ChromeDriver: $BIN_DIR/chromedriver-for-testing"
+echo ""
+echo "To use with g3, make sure $BIN_DIR is in your PATH:"
+echo "  export PATH=\"$BIN_DIR:\$PATH\""
+echo ""
+echo "Or add to your shell profile (~/.zshrc or ~/.bashrc):"
+echo "  echo 'export PATH=\"$BIN_DIR:\$PATH\"' >> ~/.zshrc"