Codex

Codex supports Streamable HTTP MCP servers through config.toml. The CLI and IDE extension share this configuration.

Add The Server

For a Dagu server without authentication:

codex mcp add dagu --url "$DAGU_MCP_URL"

For a Dagu server using builtin authentication:

codex mcp add dagu \
  --url "$DAGU_MCP_URL" \
  --bearer-token-env-var DAGU_MCP_API_KEY

--bearer-token-env-var stores the variable name, not the key. Codex reads DAGU_MCP_API_KEY from its own environment when it connects, so export it before starting Codex.

Configuration File

Both commands write to ~/.codex/config.toml:

[mcp_servers.dagu]
url = "https://dagu.example.com/mcp"
bearer_token_env_var = "DAGU_MCP_API_KEY"

Keys accepted for a Streamable HTTP server:

Key	Purpose
url	MCP endpoint. Required.
bearer_token_env_var	Environment variable holding the bearer token.
http_headers	Static request headers.
env_http_headers	Request headers whose values come from environment variables.
auth	OAuth-based authentication instead of a bearer token.
enabled	Set to false to keep the entry but stop connecting.
startup_timeout_sec, tool_timeout_sec	Connection and tool call timeouts.

Codex profiles layer on top of the base user config, so a Dagu entry can be limited to one profile by putting it in $CODEX_HOME/<name>.config.toml.

Verify

codex mcp list
codex mcp get dagu

codex mcp list --json prints the resolved configuration, which is useful when checking that the right URL and token variable were written. In an interactive Codex session, use /mcp to see whether the dagu server is connected and which tools are available.

Remove the server with codex mcp remove dagu.

Reference: Codex MCP documentation.