Source: github.com/browserbase/stagehand/releases/tag/stagehand-python%404.2.2a0.dev1605
Browserbase has published stagehand-python@4.2.2a0.dev1605, a prerelease of the Python SDK for Stagehand. The release adds the WebMCP flag to the default local Chrome launch flags. According to the release notes, Chromium versions newer than 157 require enable-features=WebMCP for WebMCP to work.
The default flag changes from --enable-features=WebMCPTesting,DevToolsWebMCPSupport to --enable-features=WebMCP,WebMCPTesting,DevToolsWebMCPSupport. The same update applies to the TypeScript and Go SDKs, and documentation and test fixtures were updated to match.
Why it matters if you build agents
If you launch local Chrome through Stagehand on a Chromium build newer than 157, WebMCP now gets the flag it needs without any extra setup on your side.
If you pass your own launch flags, check that they don't replace the defaults, since that would drop WebMCP from the enabled features.
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