Gerrit Code Review

What the Gerrit Code Review MCP server does

The Gerrit Code Review MCP server connects an MCP-compatible agent to a Gerrit 3.13 or newer instance. It lets an agent find changes, inspect review metadata and revisions, examine changed files and diffs, read comment threads, publish review comments, set label votes, and change review state.

Read operations include paginated searches using Gerrit's change query syntax, detailed change records, per-revision file statistics, individual file diffs, and comment history. Write operations cover consolidated reviews, label votes, and transitions such as submit, abandon, restore, work in progress, and ready.

How it works

The Gerrit Code Review MCP server uses the stdio transport. It authenticates with the Gerrit base URL, username, and HTTP credential supplied in the process environment. Its output uses llmxml, a semantically tagged text format intended for model consumption.

Capabilities are selected at startup with a comma-separated --groups value. The read group enables inspection tools. comment enables comment-related access, while transition enables voting and state changes. Groups can be combined, and each write group includes the read operations it needs.

With default settings, only read tools are exposed. Trail-leaving actions are also limited to changes owned by the authenticated account. Operators can explicitly widen access with --own-changes-only=false and can restrict activity to selected projects with --projects.

Setup and configuration

Install the binary from a GitHub release, use the published container image, or install it with go install. Register the executable as a stdio MCP server in the chosen client. Docker registrations pass the same environment variables into the container.

Set GERRIT_URL, GERRIT_USERNAME, and GERRIT_TOKEN. The credential is generated in Gerrit under Settings → HTTP Credentials; all three variables are required, and startup reports missing values. Flags also have GERRIT_MCP_* environment mirrors, which support per-project configuration in Claude Code and other environments that provide distinct process settings.

Tools and capabilities

The Gerrit Code Review MCP server provides these review functions:

• Search changes with Gerrit query syntax and pagination.
• Retrieve change status, ownership, labels, current revision, and messages.
• List files and change statistics for a revision, or fetch one file's diff.
• Read unresolved comment threads by default, or request all or resolved threads.
• Publish top-level, inline, range, file-level, and reply comments in one call.
• Set label values, including clearing the authenticated user's own vote with 0.
• Submit, abandon, restore, mark work in progress, or mark ready.

Optional review notifications add subscription tools for change activity. They require the server-side notification flag and Claude Code's channels contract, and poll Gerrit at a configurable interval. Subscriptions remain in memory for the session and are not recorded in Gerrit.

Limitations and notes

The target platform is Gerrit 3.13 or newer, and authentication uses HTTP credentials rather than flags. Write access is intentionally opt-in. Enabling a write group does not by itself remove the own-change restriction.

Review notifications are disabled by default. When enabled, they depend on Claude Code 2.1.80 or newer and its research-preview channels contract. Subscriptions end with the session, disappear after a server restart, and must be created again. Merged, abandoned, deleted, or no-longer-visible changes end their subscriptions with a final notification.