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

# Model judges

> Score answers with a model you choose

Use code for exact checks. Add a judge for qualities such as correctness, relevance, or clarity that need interpretation.

```ts theme={null}
import { defineEval, empty } from "anpord";
import { judge } from "anpord/validators";

const correctness = judge({
  name: "correctness",
  harness: "codex",
  model: "gpt-5.6-sol",
  rubric: "The answer explains why the result is correct, without inventing facts.",
  expected: "2 + 2 = 4",
  choices: { correct: 1, partial: 0.5, incorrect: 0 },
  threshold: 1,
});

export default defineEval({
  name: "arithmetic",
  source: empty,
  prompt: "What is 2 + 2? Explain briefly.",
  cases: [{ name: "addition", validate: correctness }],
  tasks: [{ harness: "codex", model: "gpt-5.6-sol", provider: "e2b" }],
  trials: 3,
});
```

No Effect imports or model client setup are needed in the eval file. The judge model is independent of the task model. Anpord requests the exact model you specify; an unavailable model produces an unscored judgment, not a fallback.

## Combine checks

`validate` accepts one validator or an array:

```ts theme={null}
validate: [checkToolCalls, correctness];
```

Code checks run in the task sandbox. Judges run afterward. A case passes only when its code checks pass and every judge meets its threshold. A passing judge cannot override a failed code check.

## Configuration

| Field                   | Meaning                                                        |
| ----------------------- | -------------------------------------------------------------- |
| `name`                  | Unique judge name within the case                              |
| `harness` or `provider` | Agent harness, or `provider: "openai"` for a direct model call |
| `model`                 | Exact model identifier                                         |
| `rubric`                | Instructions for the judgment                                  |
| `expected`              | Optional reference answer                                      |
| `choices`               | Labels mapped to scores between 0 and 1                        |
| `threshold`             | Inclusive pass threshold; defaults to 1                        |
| `timeoutMs`             | Total judging timeout; defaults to 120,000, maximum 300,000    |

A case accepts up to 20 validators. Each judge accepts up to 20 choices. Names, rubrics, and expected answers are checked when the eval compiles.

## Authentication

Agent judges use your organization's connection for that harness. A Codex judge can use a ChatGPT subscription connection; it does not need an OpenAI API key. When the task uses the same harness, the judge reuses its bound connection.

For direct OpenAI calls, replace `harness` with `provider: "openai"`. Configure `OPENAI_API_KEY` in the organization's environment connection, or in the server and worker environment for a self-hosted deployment. A ChatGPT subscription is not an OpenAI API key.

Keep credentials out of eval definitions, rubrics, and fixtures.

## Evidence and isolation

Judges receive the rendered task prompt, final answer, and optional expected answer. They do not receive the task workspace, transcript, MCP or CLI configuration, or task environment.

Agent judges start in a fresh sandbox after the task sandbox closes. They are instructed to grade only the supplied evidence. Tool use invalidates the judgment; it is detected, not prevented by a network firewall. For tool-use assertions, keep a code validator that inspects the mock call log.

Direct OpenAI judges use structured outputs with storage disabled. Both backends validate the response against the declared choices and require a short explanation. Timeouts, refusals, invalid responses, and provider failures produce `score: null` and make the trial `void`.

## Results

Each trial's `judgments` contains `name`, `model`, `evaluator`, `choice`, `score`, `threshold`, `reason`, `durationMs`, and `error`. The dashboard shows these separately from code checks. Judge costs are marked unpriced, so a judged run's cost total is incomplete.

Changing a judge changes the case identity used for baselines. Calibrate each rubric against known good and bad answers before trusting its scores. Repeat trials: model judgments can vary, even with the same model and rubric.