Chrome DevTools for agents now supports third-party developer tools, allowing frameworks and libraries to expose their internal runtime state to AI coding assistants via an event-based JavaScript API. Frameworks listen for a `devtoolstooldiscovery` event on the `window` object and respond with a `ToolGroup` defining custom tools. AI agents can then discover and invoke these tools through MCP calls (`list_3p_developer_tools`, `execute_3p_developer_tool`) or via `evaluate_script`. Angular has already implemented two tools — a Signal Graph tool and a Dependency Injection Graph tool — enabling agents to debug runtime-only constructs that static analysis cannot reach. React is also experimenting with the API. The feature is available in Chrome DevTools for agents v0.25.0 behind the `--categoryExperimentalThirdParty` flag.
