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

# Policy rules

> Policy YAML structure — rules, when blocks, then actions, priorities.

## Top-level policy shape

Policies are YAML files. A common layout:

```yaml theme={null}
name: my_policy
version: "1.0.0"
policy:
  environment: prod   # optional context, depending on your setup
  rules:
    - priority: 1
      name: rule_name_snake_case
      when:
        component: retrieval    # optional
        metric: context_relevance
        operator: ">="
        threshold: 0.8
      then:
        action: pass

    - priority: 2
      name: another_rule
      when:
        metric: human_reviewed
        operator: presence
      then:
        action: require_approval
        reason: "Reviewer must acknowledge"
```

## Rule fields

| Field         | Notes                                                                                                           |
| ------------- | --------------------------------------------------------------------------------------------------------------- |
| `priority`    | Integer; **unique** in this policy. **Lower = higher precedence** among matches.                                |
| `name`        | Stable identifier for logs and artifacts.                                                                       |
| `when`        | Condition on signals: at minimum **`metric`**; **`operator`**; **`threshold`** unless `operator` is `presence`. |
| `then.action` | `pass`, `block`, or `require_approval`.                                                                         |
| `then.reason` | Optional human-readable explanation.                                                                            |

## Operators

* **Comparison:** `>`, `<`, `>=`, `<=`, `==` — requires a **numeric** signal value for that metric (and component if specified).
* **`presence`** — true if a matching signal **exists**; value optional.

## Priorities and “winning” rule

All rules that match are considered. The **winning** rule is the one with the **smallest** `priority` value among matches. That rule’s `action` drives the policy outcome before cross-policy merge.

## Validation

Duplicate priorities in one policy file are rejected when the policy is loaded.

## Next

[Signals and rules](/concepts/signals-and-rules) · [validate-contract](/cli/validate-contract)