MCP Authentication | API Keys & Headers | Rime Docs

The MCP server is stateless and never stores your credentials. Instead, it reads your API key from each request and forwards it to the Rime API. Get a key from the API Tokens page. It’s the same key you use for the REST API.

Accepted headers

The MCP server accepts two headers and checks them in this order:

Header	Notes
`Authorization: Bearer <key>`	Preferred
`X-Rime-Api-Key: <key>`	Convenience alternative for clients that reserve the `Authorization` header

Tools that work without a key

Tool	API key
`list_voices`	Not required
`get_voice_details`	Not required
`generate_integration`	Not required
`check_dictionary`	Required
`normalize_text`	Required
`synthesize_speech`	Required

If you call a key-gated tool without a key, the MCP server returns a pointer to sign up rather than an error. Without a key you can still explore the catalog and generate integration code.

synthesize_speech calls the Rime API with your key, so generated samples consume credits like any other API request.