--- title: Judge page description: Configure a judge, choose the agents it scores, and read the runs it has judged. editUrl: true head: [] template: doc sidebar: hidden: false attrs: {} pagefind: true draft: false --- A judge scores runs of other agents. You'll come to the Judge page to give a judge its first version, choose which agents it scores and when, and look back at what it has done. Select a judge from the [Judges page](/admin-ui/judges) to open it. **Edit** in the header changes its name, description, team, and owner. The action menu holds **Retire judge**, **Reinstate judge**, and **Delete judge**. A retired judge takes no new runs; Prefactor only retires a judge whose runs have all finished. :::danger **Delete judge** permanently removes the judge after you confirm. You cannot undo it. ::: Above the tabs, the deployment snapshot shows which version of the judge is deployed in each environment. A hosted judge's version can move up to the next environment with **Promote**, after a confirmation, when that environment has an older version or none. A judge has no risk profile and no Activity schema tab. Only a remote judge has a Deployments tab, for the deployment tokens its own code uses, and a **Setup judge** item in the action menu that opens the getting started page. ## What you can do here - Set up the judge with a criterion and a model, and update it later. - Choose which agents the judge scores, and whether it runs on demand or on completion. - Promote a version to the next environment. - Read the judge's runs and see which run each one scored. - Check how the judge's own runs perform. Each of these has a CLI command and an API operation. [Set up a judge from the CLI](/cli/judges#web-app-cli-and-api) lists them next to the controls on this page. ## Overview tab The Overview tab holds the agents the judge scores and a summary of its recent work. The **Judging** box lists the agents whose runs this judge scores, each with its trigger: **On demand** or **On completion**. [Evals](/platform/evals#triggers) explains the difference. **Add agent**, in the box's action menu, opens a dialog where you choose an agent and a trigger. It is unavailable when no agents are registered or every agent is already attached. A row's action menu has **Remove**, which asks you to confirm before the judge stops scoring that agent. Beside it, the **Instances** box counts the judge's own runs by state, using the same states as the [Agent page › Overview tab](/admin-ui/agent/overview#instances-summary). **Recent activity** lists the five most recent judge runs, each naming the agent and run it scored, with **View instance** to open it. ## Configuration tab A hosted judge's configuration is its list of versions. Pick a version from the **Version** dropdown to see the environments it is deployed in, its model, criterion, and system prompt template, and the recent runs on that version. A new judge has no versions, so the tab shows **Create judge**. Once it has one, the button reads **Update judge**. Either opens a dialog with these fields: - A template picker: **Write your own**, or one of the built-in criteria — Completeness, Correctness, Hallucination, Refusal, Tool invocation, Tool response handling, PII detection, and Toxicity — each with a one-line description. Choosing a template fills in the criterion. - **Criterion** — what the judge looks for. - **Model** — one of the models from your [LLM providers](/admin-ui/account/llm-providers), grouped by provider. The dialog asks you to add a provider and a model first when you have none. - **Version identifier** — defaults to the current date and time. - **Use a custom system prompt template** — reveals **System prompt template**. The only variable is `{{ criterion }}`. **Update judge** starts the dialog pre-filled from the selected version, and **Start from a template** brings the template picker back. Submitting saves a new version and deploys it to your lowest environment. If the judge already has a version with the same identifier, template, criterion, and model, Prefactor reuses it. Existing versions never change. To change the criterion, template, or model, update the judge, which creates a new version. ## History tab Each row is one run of the judge, including runs still in progress. The columns are Time, Status, Instance ID, Environment, Version, and Alerts, with **View** to open the run. Under the instance ID, a "Judging" line names the agent and run that judge run scored and links to it. ## Metrics tab Run health for the judge over the time range you choose, with the same figures as the [Agent page › Metrics tab](/admin-ui/agent/quality). ## Related - [Evals](/platform/evals) — the model behind judges, triggers, and judge runs. - [LLM provider](/platform/concepts/llm-provider) — the models a hosted judge runs on. - [Judges page](/admin-ui/judges) — the list of judges. - [Set up a judge from the CLI](/cli/judges) — the same setup from the command line, including remote judges. - [Agent page › Overview tab](/admin-ui/agent/overview#judges) — where an agent's own judges are added. - [Agent › Instance › Quality tab](/admin-ui/agent-instance/quality) — each judge's verdict on a single run.