Codex setup

Codex setup

Codex supports MCP servers in the CLI and IDE extension. Configuration is stored in ~/.codex/config.toml Trusted projects can also use .codex/config.toml inside the repository.

Option 1: OAuth

1. Create an OAuth application — see the OAuth application setup guide with the forms scope.
2. Add the FormDesigner MCP server to config.toml

[mcp_servers.formdesigner]
url = "https://mcp.formdesigner.pro/v1/mcp"

Redirect URI for the OAuth application

By default, Codex uses a local callback on an ephemeral port. If the FormDesigner OAuth application needs a predefined redirect URI, pin the callback port in config.toml

mcp_oauth_callback_port = 5555

[mcp_servers.formdesigner]
url = "https://mcp.formdesigner.pro/v1/mcp"

Add http://127.0.0.1:5555/ to the FormDesigner OAuth application redirect URIs. You can also add http://localhost:5555/ If Codex shows a redirect URI with an extra path or callback ID during login, register the exact full URI shown by Codex.

Log in from the terminal:

codex mcp login formdesigner

After login, start a new Codex chat or check the connection with /mcp in Codex CLI.

Option 2: client credentials

1. Create an OAuth application — see the OAuth application setup guide with the forms scope and enable useClientCredentials.
2. Store client_id and client_secret in the FORMDESIGNER_CLIENT_ID and FORMDESIGNER_CLIENT_SECRET environment variables.
3. Add configuration that sends headers from environment variables:

[mcp_servers.formdesigner]
url = "https://mcp.formdesigner.pro/v1/mcp"
env_http_headers = { "X-Client-Id" = "FORMDESIGNER_CLIENT_ID", "X-Client-Secret" = "FORMDESIGNER_CLIENT_SECRET" }

OAuth is best for personal interactive setup. Client credentials are useful for automation, containers, and team environments where browser OAuth is inconvenient.

Test prompt: ask Codex to create a test form in FormDesigner or list your forms.