---
title: "Judges"
description: "What a judge does and where its labels show up."
sidebar:
  label: "Judges"
seo:
  title: "Judges | Judgment Docs"
  description: "What a judge does and where its labels show up."
---

A judge reads a trace or a session and applies one of two or more labels you define. You pick the **Evaluation method** when you create the judge, and it can't change later:

- **Agentic Judge**: an Agent judge follows your rubric and reads the trace to decide. Most judges are Agent judges.
- **Deterministic conditions**: a Condition judge checks the trace's duration, LLM cost, errors, or the names and attributes of its spans. It has exactly two labels: the first means the conditions matched, the second that they didn't (**Matched** and **Not matched** by default). Use one for cost, latency and error alerts.
- **Custom code**: a Code judge runs Python you upload. You create and update Code judges through the API or MCP, not in the app. See [Code judge bundle](/documentation/reference/code-judge-bundle).

## What judges are for

- **Watch for a known failure.** Turn the judge on for [live traffic](/documentation/judges/run-on-live-traffic) and every new trace gets a label.
- **Alert your team.** An [action](/documentation/judges/judge-actions) sends an email, posts to Slack, adds the trace to a dataset or runs another judge when the judge returns a given label.
- **Grade tests.** The same judges grade each trace when you [run a test](/documentation/tests/overview) over a dataset.
- **Index your data.** Labels let the Judgment Agent answer questions across all your traces without reading every one. [Labels as indexes](/documentation/agents/labels-as-indexes) explains how.

## Where labels live

Labels are stored as judge results next to your traces. You can see them in three places:

- On the judge's **Labels** tab, with the traces each label was applied to.
- In the trace view and as filters on **Traces**.
- In SQL. Judgment's virtual SQL (vsql) exposes judge results in `telemetry.scores` and the label definitions in `config.behaviors`. API and SQL names still say behavior; it means label.

The Judgment Agent and your coding agent (through the MCP `sql_query` tool) both read these tables. See [Query with SQL](/documentation/agents/query-with-sql).

A judge has three tabs: **Details** (run settings, evaluation method and actions), **Labels**, and **Alignment** (see [Align a judge](/documentation/judges/align-a-judge)).