Chrome 149 DevTools ships several major updates: the DevTools for agents MCP server and CLI are now stable (v1.1.1), with new custom third-party tool support and WebMCP debugging. The AI assistance panel gets a significant UI overhaul including widget-based responses, Lighthouse integration, Gemini 3 under the hood, and a 'Copy to coding agent' button. Experimental WebMCP debugging tools land in the Application panel, letting developers inspect, run, and monitor LLM-callable web tools. CSS code completion powered by Gemini is now available in the Styles tab. APCA color contrast guidelines graduate from experimental to stable settings. The Responsive device mode now uses a dynamic user agent instead of a hardcoded decade-old Android string. Additional fixes cover Console, Network HAR exports for SSE, Performance Core Web Vitals tracking, and more.
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Dev Tools for agentsAI assistanceWebMCPCode completion for CSSAPCA color contrast guidelines promoted to stableDynamic Device Mode user agentOther highlights13.9K Impressions1 Comment