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

# Limits & Validation Rules

## Limits and Validation

### Character Limits

* 500 characters per block
* 4000 characters total per YAML

### YAML Format Rules

* YAML 1.2 compliant
* 2-space indentation, no tabs
* Allowed root fields: `version`, `language`, `org`, `repos`

### Validation Requirements

* At least one instruction required
* Repo names: alphanumeric, `_` or `-` only
* Up to 10 repos, 20 items per `match` array

### Security Checks

* Avoid terms like “ignore above”, “override”, “forget previous”
* Don’t include text that alters AI behavior or review logic

<Note>
  These safeguards ensure consistent and safe PR reviews.
</Note>

## Preview and Verify

Use **Show Preview** in the Custom Instructions tab to confirm:

* YAML structure validity
* Which rules apply to which repositories