magic-mcp fails with "fetch is not defined": which Node.js version do I need?

3 answers

• Best answerAgentArmor teamTeam3d ago

  Status: explained. A maintainer identified the likely cause, and the standalone server behind this issue has since been retired, so this error no longer applies to the current package.

  The maintainer said the failure was likely caused by the Node.js version running the MCP server: fetch was added in Node.js 18 (2022) but only as an experimental feature, with stable support arriving in Node.js 21 (October 2023). The recommended fix is to run the server on Node.js 21 or newer. The thread does not confirm whether the reporter upgraded, so treat this as the maintainer's diagnosis rather than a verified fix.

  Separately, a contributor's closing comment states that as of v0.2.0 the standalone magic-mcp server is retired and the package is now a thin proxy to the unified 21st MCP server at https://21st.dev/api/mcp. Failures like this one were symptoms of the old backend, and the old API keys were reset. Current setup per that comment: get a new key at https://21st.dev/mcp and run:

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  npx @21st-dev/cli@latest init
  

  Existing @21st-dev/magic configs continue to work because they now proxy to the new server.

  General advice: the new key is a credential, so keep it out of source control and logs. Also note that any magic-mcp keys issued against the old backend no longer work.

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• AgentArmor teamTeam3d ago

  What a GitHub user tried on GitHub (Didn't work)

  The reporter connected to the magic-mcp server and made a tool call that failed with fetch is not defined. The issue body provides no workaround.

  Source: https://github.com/21st-dev/magic-mcp/issues/17 (opens external site) ↗

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• AgentArmor teamTeam3d ago

  What @bunasQ tried on GitHub (Outcome unclear)

  A maintainer suggested upgrading the Node.js runtime to version 21 or newer, where fetch is fully stable instead of experimental as in Node.js 18 (where it was added in 2022). The thread does not record whether this was tested.

  Source: https://github.com/21st-dev/magic-mcp/issues/17#issuecomment-2809535311 (opens external site) ↗

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