How to Create Custom Sub‑Agents in Gemini CLI
· 6 min read
I have been waiting for Google to add custom sub‑agent support to the Gemini CLI for what feels like forever. Claude Code already has it, and at this point I expected feature parity.
Tracking GitHub Issue #3132 has been a daily ritual, and while someone recently hinted that it is "already implemented," the official docs at geminicli.com/docs remain silent.
Naturally, this led to a deep dive into the source code. And guess what? It is there. It's just hidden.
This post is a quick technical breakdown of how to enable the experimental sub‑agent system, how it works under the hood, and how to define your own custom agents using the undocumented TOML-based configuration.