> ## Documentation Index > Fetch the complete documentation index at: https://openrouter.ai/docs/llms.txt > Use this file to discover all available pages before exploring further. # Rule ## Fields | Field | Type | Required | Description | | ---------- | --------------------------------------------------------------------------------------------------------------- | -------------------- | ----------- | | `field` | [components.FieldT](../components/fieldt.mdx) | :heavy\_check\_mark: | N/A | | `operator` | [components.Operator](../components/operator.mdx) | :heavy\_check\_mark: | N/A | | `value` | [Optional\[components.ObservabilityFilterRuleGroupValue\]](../components/observabilityfilterrulegroupvalue.mdx) | :heavy\_minus\_sign: | N/A |