There is a Rust crate and a Ruby gem for Gemini Notebook (formerly NotebookLM), both built from this server's REST API. If your language is neither, you do not have to wait for someone to write one. The server publishes a specification, and a specification is a client generator's input.
Search crates.io for a NotebookLM client and you find one crate, nblm-core.
It targets NotebookLM Enterprise — the Google Cloud product, not the
Gemini Notebook you log into with a personal account — it has not been published since
November 2025, and it served 41 downloads in the last ninety days. For the
consumer product, the Rust shelf is empty.
That is not because Rust is unsuited to the job. It is because the hard part of this problem is not HTTP.
MCP gives an agent a server to talk to. UTCP — the Universal Tool Calling Protocol — gives it a description and gets out of the way. There is no protocol server, no wrapper process, no second hop: the client reads a manual once at startup, and from then on it calls your API directly, the way any other HTTP client would.
That difference is the whole protocol, and it decides what "supporting UTCP" means. It is not something you implement. It is something you publish.