# Agent tool correctness

`AgentToolCorrectnessJudge` checks if an agent called the right tools with valid arguments and interpreted the outputs accurately. It’s invaluable for diagnosing production agents that orchestrate APIs, databases, or internal services.

```python title="Inspect tool usage"
from opik.evaluation.metrics import AgentToolCorrectnessJudge

payload = """TOOL weather_api(city='Paris') -> 12°C and raining.
AGENT: Responded "Sunny and warm".
"""

metric = AgentToolCorrectnessJudge()
score = metric.score(output=payload)

print(score.value)   # 0.0–1.0 after normalisation
print(score.reason)
```

## Inputs

| Argument | Type  | Required | Description                                                      |
| -------- | ----- | -------- | ---------------------------------------------------------------- |
| `output` | `str` | **Yes**  | Payload describing the task, tool calls, and observed behaviour. |

## Configuration

| Parameter      | Default      | Notes                                                      |
| -------------- | ------------ | ---------------------------------------------------------- |
| `model`        | `gpt-5-nano` | Upgrade to a larger evaluator if analysing lengthy traces. |
| `temperature`  | `0.0`        | Keep low for repeatable scoring.                           |
| `track`        | `True`       | Controls Opik tracking.                                    |
| `project_name` | `None`       | Override logging destination.                              |

The judge emits an integer between 0 and 10 (scaled to 0–1 by Opik); read `score.reason` to pinpoint incorrect calls, missing validations, or misinterpreted outputs.

## Related pages

- [Overview](./evaluation-metrics-overview.md)
- [Heuristic metrics](./evaluation-metrics-heuristic-metrics.md)
- [Hallucination](./evaluation-metrics-hallucination.md)
- [LLM Juries](./evaluation-metrics-llm-juries.md)
- [G-Eval](./evaluation-metrics-g-eval.md)
- [Conversation-level GEval Metrics](./evaluation-metrics-g-eval-conversation-metrics.md)
- [Compliance risk](./evaluation-metrics-compliance-risk.md)
- [Prompt uncertainty](./evaluation-metrics-prompt-diagnostics.md)
- [Moderation](./evaluation-metrics-moderation.md)
- [Meaning Match](./evaluation-metrics-meaning-match.md)

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