Connect Codex to live documentation.

A remote reference inside your coding agent

Codex can connect to remote MCP servers over Streamable HTTP. Docsy resolves documentation libraries, discovers indexed editions and provides source-linked excerpts, while Codex continues to work with your local code. The two systems complement each other; Docsy is not a substitute for reading the primary documentation or running tests.

Use https://docsy.remcp.site/mcp as the hosted MCP URL. Docsy authenticates remote MCP sessions through OAuth. Do not paste private tokens or your Docsy password into a shared config file, chat message or README.

Install using Codex CLI

Open a local terminal with the Codex CLI installed. Add the remote HTTPS endpoint using the documented --url option, and complete the OAuth flow when Codex requests it. A browser will open to authorize Docsy; inspect the permissions, sign in to your own account and allow the requested read-only documentation access.

The add command saves the endpoint configuration and, in recent Codex CLI versions, may immediately start OAuth. Complete that prompt if it appears; otherwise run codex mcp login docsy separately. Use codex mcp list after login to inspect the server; in the interactive Codex terminal, /mcp shows configured server status. The Codex IDE extension shares this MCP configuration with the CLI.

• Add the Docsy server with the remote HTTPS URL, not a local stdio command.
• Complete OAuth automatically after add, or run codex mcp login docsy if no prompt appears.
• Review Docsy's read-only permissions before approving.
• Check codex mcp list or /mcp before relying on the tools.

codex mcp add docsy --url https://docsy.remcp.site/mcp

If Codex did not open the sign-in page

Recent Codex CLI versions may start OAuth automatically as soon as the server is added. Finish that browser flow before running more commands. Only if it was skipped, closed or expired, start the manual login command below. Then check that the server is registered.

Use /mcp inside an interactive Codex session to inspect tool status. A saved server entry or a successful copy to clipboard is not evidence of authenticated access. Run a test query with a source URL to verify retrieval.

codex mcp login docsy
codex mcp list

Or configure Codex manually

Codex also reads MCP server declarations from ~/.codex/config.toml. Add the following table once; do not replace unrelated Codex settings or duplicate an existing docsy entry. The same configuration is shared with the IDE extension.

After saving the file, run codex mcp login docsy to complete authentication. Codex stores OAuth credentials separately; a plain URL entry is sufficient for discovery and does not belong in a public source repository together with personal secrets.

[mcp_servers.docsy]
url = "https://docsy.remcp.site/mcp"

Verify one source-linked retrieval

Ask Codex: 'Use Docsy to find React useEffect cleanup guidance for the indexed React edition and show the original source URL.' Then try: 'Find the official Next.js 16.4.2 revalidation documentation, and verify the source link.'

Useful answers name the resolved library, show which version was selected and link to the primary source. If a requested edition is not indexed, ask Codex to list the available library versions instead of presenting guidance from another edition as though it matched.

For routine development, add an instruction to your project's AGENTS.md telling Codex to consult Docsy for version-sensitive library APIs, while still reading source references and validating code changes with tests.

Troubleshoot authentication or tool discovery

If codex mcp list shows Docsy but authorization is missing, run codex mcp login docsy again and inspect the login result. A direct anonymous HTTP request returning 401 does not prove the service is offline; the correct test uses the authenticated MCP client and an actual tool call.

If Codex shows OAuth registration or callback errors, verify that you installed a current Codex version and that your browser can complete the loopback callback. Do not disable OAuth or put a long-lived bearer token into an AGENTS.md file just to bypass an authentication failure.

If a remote server is visible but no result appears, check the current /mcp status, confirm your connection permissions and retry with a focused package-and-version query. You can revoke access at any time from Docsy's Connected applications dashboard.