Barbel is a self-hosted GitLab bot that helps people review merge requests. The part that matters is what it will not do: it never approves or blocks anything. It stays an assistant, not a required approver.
On each merge request it keeps one comment up to date with three things: a plain-language summary of what changed, the parts worth a closer look, and whether the changelog was updated (checked against Keep a Changelog 1.1). The reviewer still makes every call. Barbel just gets them oriented faster.
It is written in Go and runs on your own infrastructure. It needs a GitLab project access token scoped to the API and nothing more, granted per project rather than as a personal token, and every secret (the token, the LLM key, database and webhook credentials) comes from the environment or a secret manager. It is licensed AGPL-3.0, so anyone who runs a modified copy as a network service owes their users the source.
Still early. The design and roadmap live in the project wiki.