Secure MCP access to Onyx search, chat, projects, and administration.
To add Onyx MCP to Claude, run the install command below or copy the ready-made config for Claude Code, Claude Desktop, Cursor and VS Code further down. Restart your client after adding it and its tools show up in your next conversation. It needs 5 environment variables, listed below.
Install
npx -y onyx-mcp@0.2.1Environment variables
ONYX_API_URLSet in your MCP configONYX_API_TOKENSet in your MCP configONYX_DEFAULT_PERSONA_IDSet in your MCP configONYX_MCP_ENABLE_WEB_FETCHSet in your MCP configONYX_MCP_WEB_FETCH_ALLOWLISTSet in your MCP configInstall with your client
claude mcp add onyx --env ONYX_API_URL=<YOUR_ONYX_API_URL> --env ONYX_API_TOKEN=<YOUR_ONYX_API_TOKEN> --env ONYX_DEFAULT_PERSONA_ID=<YOUR_ONYX_DEFAULT_PERSONA_ID> --env ONYX_MCP_ENABLE_WEB_FETCH=<YOUR_ONYX_MCP_ENABLE_WEB_FETCH> --env ONYX_MCP_WEB_FETCH_ALLOWLIST=<YOUR_ONYX_MCP_WEB_FETCH_ALLOWLIST> -- npx -y onyx-mcp@0.2.1
Run this in a terminal to add the server to Claude Code.
What this does
Onyx MCP exposes a set of tools to Claude over the Model Context Protocol. After you add it to claude_desktop_config.json (snippet above) and restart Claude Desktop, those tools become callable inside any conversation.
Requirements
This server needs the following environment variables to be set before it can run:
ONYX_API_URL ONYX_API_TOKEN ONYX_DEFAULT_PERSONA_ID ONYX_MCP_ENABLE_WEB_FETCH ONYX_MCP_WEB_FETCH_ALLOWLIST
Set these via the env object in your MCP config (see claude_desktop_config.json snippet above).
Frequently asked questions
How do I install Onyx MCP?
Run the Claude Code command in the install section to add Onyx MCP to Claude Code, or copy the ready-made config for your client from the install section on this page. Restart your client afterwards and the tools appear in your next conversation.
Which clients work with Onyx MCP?
This page carries setup and config for Claude Code, Claude Desktop, Cursor and VS Code. Any other MCP client that accepts a standard server config can connect to Onyx MCP as well.
Does Onyx MCP need an API key?
Yes. Before it can run, set these environment variables: ONYX_API_URL, ONYX_API_TOKEN, ONYX_DEFAULT_PERSONA_ID, ONYX_MCP_ENABLE_WEB_FETCH, ONYX_MCP_WEB_FETCH_ALLOWLIST. They go in the env block of your MCP config.
Imported from the Official MCP Registry. The details above come from the registry entry; the maker can claim this listing to correct them, add docs, and see its traffic.
Is this your MCP server?
Claim this listing to see its traffic, fix details yourself, and skip the review queue on future updates.
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