# starlette.exceptions.HTTPException: 422 Unprocessable Entity

- **ID:** `python/starlette-request-validation-error`
- **Domain:** python
- **Category:** data_error
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

请求体或参数验证失败，例如缺少必填字段。

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| 3.x | active | — | — |

## Workarounds

1. **** (95% success)
   ```
   from pydantic import BaseModel
class Item(BaseModel):
    name: str
    price: float = Field(..., gt=0)
   ```

## Dead Ends

- **** — 会导致数据不完整，业务逻辑错误 (90% fail)
- **** — 不解决验证问题，只是绕过 (80% fail)