Codex CLI

For developers using the Codex CLI.

Confirmed as of v0.146.0 · August 4, 2026

Open your terminal
Add the Valency MCP server, pinning the sign-in port:
```
codex mcp add valency-mcp --url https://labs.valency.io/mcp/ \
  -c mcp_oauth_callback_port=33418
```
Codex detects that the server uses OAuth and starts sign-in straight away. Complete it when the browser opens, then return to the terminal.
If you ever need to sign in again — after a token expires, or if you clear credentials:
```
codex mcp login valency-mcp -c mcp_oauth_callback_port=33418
```
Valency only accepts sign-in redirects on a fixed list of local ports, so the port has to be pinned on the command that signs you in — which is codex mcp add itself. Without mcp_oauth_callback_port, Codex picks a random one and sign-in fails with redirect_uri is not registered. Codex also builds its callback address from the server URL, so keep the trailing slash on /mcp/.
If Codex reports the port is already in use, see what to do when the callback port is busy. You can also set the port once in ~/.codex/config.toml instead of on every sign-in.

OAuth login is only supported for streamable HTTP MCP servers. Sign in with the email you used to register at app.valency.io — it does not have to match the email on your ChatGPT account.
Start Codex:
```
codex
```
Run /mcp inside Codex to confirm Valency is listed with its tools.
Start a new conversation and ask: "Search for papers about quantum computing" (more prompt ideas)

Success: You see paper results in your terminal. You can also explicitly invoke Valency tool calls.

Need help?

If something isn't working, check Troubleshooting for common fixes. See the FAQ for general questions, or report an issue if you're still stuck.