Core Concepts

Browser lifecycle: Browser starts automatically on first tool call using a persistent Chrome profile. Configure via CLI args in the MCP server configuration: npx chrome-devtools-mcp@latest --help. Addional tooling can be enabled by providing the following flags:

For extension tooling, use the --categoryExtensions flag.
For memory tooling, use the --memoryDebugging flag.

Page targeting: Page-scoped tools require a pageId parameter to target a specific page. Use list_pages to see available pages and their IDs (e.g. pageId: 1), or use the ID returned when creating a page with new_page. Note: For evaluate_script, pageId is required when targeting pages. However, when --categoryExtensions is enabled, pageId is optional so you can pass serviceWorkerId instead to evaluate inside an extension background service worker. Element interaction: Use take_snapshot to get page structure with element uids. Each element has a unique uid for interaction. If an element isn't found, take a fresh snapshot - the element may have been removed or the page changed.

chrome-devtools

Core Concepts

Workflow Patterns

Before interacting with a page