> ## Documentation Index
> Fetch the complete documentation index at: https://runmirrors.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# CI gate

> Block agent regressions at the pull request, Vercel-style.

The CI gate replays your eval set against every pull request that touches your agent, and reports a **Mirrors eval gate** status check on the PR. Make the check required and regressions block the merge — before they reach a customer.

## How it works

On each PR against your base branch, Mirrors fetches your agent's code at the configured path, runs the bound eval set against your mirror with the **candidate** agent, and diffs the results against the **baseline** (the current agent). The check lands as in-progress → awaiting review, with a candidate-vs-baseline diff in the dashboard (`/ci/<check-id>`) where you approve or reject — flipping the GitHub check.

## Set it up

<Steps>
  <Step title="Connect GitHub">
    In the dashboard, go to **Quickstart → CI eval gate** and click **Connect GitHub**. This installs the Mirrors GitHub App; GitHub redirects you back with the installation already linked to your workspace.
  </Step>

  <Step title="Bind a repo">
    Pick the repository and bind it to:

    * a **mirror** (the twin to replay against),
    * a **validation eval set** (what runs on each PR),
    * the **agent path** in the repo (e.g. `agent/agent.py`) — the webhook fetches this file on each PR,
    * the **base branch** (default `main`).
  </Step>

  <Step title="Make it required">
    Click **Make required** on the repo row to turn **Mirrors eval gate** into a required status check (needs the App's Administration permission), or add it manually under the repo's **Settings → Branches**. Merges now block until the gate passes review.
  </Step>
</Steps>

## Reviewing a check

Each check links to a dashboard page showing the candidate-vs-baseline diff per eval case. **Approve** marks the check green; **Reject** fails it. A regression is a decision, not a surprise.

<Note>
  An installation can only be linked to one workspace. If you see "already linked to another workspace", the GitHub account was claimed elsewhere — connect from that workspace or use a different GitHub org.
</Note>