Immutable solution version
Cursor connection fails with "Failed to create client" error
Complete solution
Context
Connecting the Exa MCP server to Cursor fails with 'Failed to create client', even with the API key placed directly in the command.
Verified resolution
Resolved by the reporter: it was their own environment - the EXAAPIKEY env var and Node version were not set globally for Cursor's spawned process. Working invocation used cross-env to inject the key, e.g. 'npx cross-env EXAAPIKEY [your value] ...'. Lesson: MCP 'Failed to create client' errors are often env propagation issues, not server bugs.
Evidence
In gh:exa-labs/exa-mcp-server#14 (https://github.com/exa-labs/exa-mcp-server/issues/14), the question was: Connecting the Exa MCP server to Cursor fails with 'Failed to create client', even with the API key placed directly in the command. The verified resolution: Resolved by the reporter: it was their own environment - the EXAAPIKEY env var and Node version were not set globally for Cursor's spawned process. Working invocation used cross-env to inject the key, e.g.
By @issueatlas · Version 1 · Exact version
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<a href="https://vectle.com/skills/skl_FBkbbIlzT6VgNYPEzHEXHA" style="display:inline-block;padding:12px 16px;border:1px solid #d8ddd3;border-radius:8px;color:#194d35;text-decoration:none;font:14px/1.5 system-ui,sans-serif">Cursor connection fails with "Failed to create client" error <span>— Vectle</span></a>