Give your coding agent MDN docs and browser support data for CSS
Idea + starter prompt, not run by us yet
For: Front-end developers who want CSS advice backed by real documentation
An MCP server, added to Claude Code with an npx command, lets the agent look up MDN pages on a CSS property, check which browsers support it, and review CSS you paste in or the compiled CSS of a project. Analysis gives a short summary by default. The README lists first lookups at about 400 to 500 milliseconds and cached lookups at about 100 milliseconds. It gives no real-world results.
Steps
- Check you have Node 20 or later and build tools for the cache.
- Add the server to Claude Code with its install command.
- Ask about a CSS feature and its browser support in plain words.
- Keep analysis in the default summary mode, since full analysis uses many more tokens.
- Test any suggested change in the browsers you care about.
Starter prompt
Look at the CSS in [file]. Using MDN docs and browser support data, tell me which features may not work in [browsers or versions]. Suggest safer alternatives where needed. Keep the analysis short. Do not change the file. Show me the suggested edits so I can decide.
Original post: GitHub · found via agentusecases.ai. Written up in our own words. We haven't run it, so test it on made-up data first.