Firecrawl MCP server crashes: 'Server does not support completions' on startup
Firecrawl MCP server (firecrawl-mcp, run via npx on macOS with Node v25.2.0) crashes immediately when used with Claude Code CLI: 'Error: Server does not support completions (required for completion/complete)'. The same error appears in VS Code and Claude Desktop with firecrawl-mcp@3.6.0. What version or configuration fixes this?
Originally asked on GitHub: https://github.com/firecrawl/firecrawl-mcp-server/issues/133
6 answers
Fixed in firecrawl-mcp 3.6.1 (released 2025-11-15). The maintainer pinned @modelcontextprotocol/sdk to 1.18 in their fastmcp fork after finding that SDK 1.22 is incompatible; the server crashes during startup when the 1.22 SDK is installed. To fix it, completely reinstall firecrawl-mcp at 3.6.1 or later. With npx, run
npx -y firecrawl-mcp@3.6.1(ornpx -y firecrawl-mcp@latest). For a global install, runnpm install -g firecrawl-mcpafter removing the previous global install, since the maintainer noted you have to reinstall it completely. Several users confirmed that installing the latest version resolved the crash. If you cannot upgrade, one user reported that firecrawl-mcp version 2.0.0 works, and the original reporter used the Firecrawl HTTP API directly as a workaround. The crash occurs even with a valid FIRECRAWL_API_KEY, so it is not an authentication problem. If npx still serves a stale cached copy after reinstalling, clearing the npx cache directory (for example the_npxfolder under your npm cache) and retrying is a general cleanup step, not an official Firecrawl instruction.Did this work for you?What a GitHub user tried on GitHub (Didn't work)
Reporter configured the server with
claude mcp add --transport stdio firecrawl --env FIRECRAWL_API_KEY=fc-xxx -- npx -y firecrawl-mcp, thenclaude mcp listshowed the server as failed with the completions error.Source: https://github.com/firecrawl/firecrawl-mcp-server/issues/133 (opens external site)
Did this work for you?What @treadingcream tried on GitHub (Didn't work)
User installed firecrawl-mcp globally (
npm install -g firecrawl-mcp, resulting in firecrawl-mcp@3.6.0) and ranFIRECRAWL_API_KEY=**** firecrawl-mcp, getting the same immediate crash with the completions error.Did this work for you?What @frost19k tried on GitHub (Didn't work)
User tried versions going back to firecrawl-mcp 3.4.0 and Firecrawl API 2.5.0, but the crash still happened.
Did this work for you?What @coradinibr tried on GitHub (Worked)
User reported that firecrawl-mcp version 2.0.0 works as a workaround.
Did this work for you?What @coradinibr tried on GitHub (Worked)
After the maintainer pinned the MCP SDK to 1.18 and released 3.6.1, the user installed the latest version and confirmed the server started successfully.
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