How to install Firefox DevTools MCP in Codex

To install Firefox DevTools MCP in Codex, run "codex mcp add firefox-devtools-mcp -- npx -y @mozilla/firefox-devtools-mcp" in your terminal, then type /mcp in Codex to check it.

Built from the published package · server updated 6 days ago

Run the install command

In a terminal, run:

codex mcp add firefox-devtools-mcp -- npx -y @mozilla/firefox-devtools-mcp

2
Check it
Inside Codex, type /mcp to see the server and its tools.

MCP servers run with your permissions. If Firefox DevTools MCP needs an API key, add it under env in the config. Check its README.

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Questions

Does Firefox DevTools MCP work in Codex?

Yes. Codex supports mcp servers in the codex cli and ide extension, and Firefox DevTools MCP installs with the steps above.

Firefox DevTools MCP does not show up in Codex. What now?

Restart Codex fully, check the JSON is valid, and make sure Node.js (for npx) is installed. See common MCP errors and fixes.

Is Firefox DevTools MCP safe?

It scores 81 of 100. Review the code before you install it, and only give it the access it needs. Grades and details.