Connect Codex to Marka's MCP server

To connect an MCP server to Codex, run codex mcp add with Marka's server URL https://joinmarka.com/api/mcp and --bearer-token-env-var MARKA_API_KEY, then restart Codex. Codex reads your API key from that environment variable.

1. Create an API key and set it as MARKA_API_KEY (see Before you start).
2. Run the codex mcp add command under Connect, or add the same entry to ~/.codex/config.toml.
3. Restart Codex, then check that it worked.

Codex talks to Marka's hosted gateway over Streamable HTTP, so there is nothing to install.

How Codex connects to an MCP server

Codex keeps its MCP servers in ~/.codex/config.toml, one [mcp_servers.<name>] table per server, and codex mcp add writes that table for you. It speaks two transports:

• Streamable HTTP, for a remote server: codex mcp add <name> --url <url>. If the server wants a bearer token, --bearer-token-env-var <VAR> names the environment variable Codex reads it from, so the token itself never goes in the file.
• stdio, for a local server that Codex starts itself: codex mcp add <name> -- <command> [args].

Codex has no option for the older SSE transport. Marka's gateway is Streamable HTTP, so it uses the first form.

codex mcp list shows the servers in your config, and /mcp inside a Codex session lists the tools they expose.

Connect

Run the command, or add the equivalent entry to ~/.codex/config.toml by hand. Both do the same thing.

codex mcp add marka --url https://joinmarka.com/api/mcp --bearer-token-env-var MARKA_API_KEY

# Equivalent entry in ~/.codex/config.toml
[mcp_servers.marka]
url = "https://joinmarka.com/api/mcp"
bearer_token_env_var = "MARKA_API_KEY"

Codex stores only the variable's name. It reads MARKA_API_KEY each time it starts and sends the value as a bearer token, so the key itself is never written to Codex's config.

Restart Codex to load the Marka tools.

Check it worked

codex mcp list should now show marka. Then check the key. A good key prints your user and plan as JSON.

curl -sS https://joinmarka.com/api/v1/me -H "x-api-key: $MARKA_API_KEY"

Then ask Codex to search Marka. An answer drawn from the live catalogue proves the MCP connection.

To change the key, change MARKA_API_KEY and restart Codex. Nothing in the config needs editing.

Sign in with your browser instead of an API key

Codex can also sign in to Marka through your browser, with no key. Add the server without a bearer token. Codex checks whether the server supports OAuth when you add it and starts the sign-in; if it does not start, or you need to sign in again, run the login command. If you already added Marka with a key, remove that entry first with codex mcp remove marka.

codex mcp add marka --url https://joinmarka.com/api/mcp

codex mcp login marka

Your browser opens Marka's consent page, which names the client and the address it will return to. Sign in if asked, check both, and press Allow.

To disconnect, clear Codex's stored sign-in:

codex mcp logout marka

Or open Settings → Connected apps on Marka and disconnect the client there. That ends its access immediately and revokes every token it holds.

Common questions

How do I add an MCP server to Codex?

Run codex mcp add <name> --url <url> for a remote server, or codex mcp add <name> -- <command> [args] for a local one that Codex starts itself. For Marka, use the remote form with the command under Connect. Restart Codex afterwards.

Does Codex support remote MCP servers?

Yes, over Streamable HTTP. Codex has no option for the older SSE transport, and Marka's gateway is Streamable HTTP, so it works with --url.

Where does Codex store its MCP servers?

In ~/.codex/config.toml, one [mcp_servers.<name>] table per server. codex mcp add writes the table for you, and you can edit the file by hand instead.

How do I check that Codex sees the Marka tools?

Run codex mcp list, which should show marka, or type /mcp inside a Codex session to list the tools the server exposes. See Check it worked to test the key as well.