Codex CLI

Add the serverCopy Anchor Link

Codex reads MCP servers from ~/.codex/config.toml. Add twin memory with its URL, the environment variable that holds your key, and the end user as a static header:

[mcp_servers.twin-memory]
url = "https://api.twinmemory.dev/v1/mcp"
bearer_token_env_var = "TWIN_MEMORY_API_KEY"
http_headers = { "X-Twin-Account" = "user_42" }

• bearer_token_env_var names an environment variable. Codex sends its value as Authorization: Bearer ....
• http_headers holds headers with fixed values.
• env_http_headers maps a header to an environment variable instead, for example env_http_headers = { "X-Twin-Account" = "TWIN_ACCOUNT" }.

Set the key in the environment Codex runs in:

export TWIN_MEMORY_API_KEY="tm_..."

Use a read key if Codex should only search and read: it cannot write or erase. Use a read and write key if Codex should save what it learns: the server then lists memory_add too.

codex mcp add NAME --url URL also adds a server, but we could not confirm a flag for the bearer variable, so set it in config.toml as above.

If no tools are listed, see Troubleshooting.

Sources checked 2026-10-21: learn.chatgpt.com/docs/extend/mcp?surface=cli.