<!--
name: 'System Block: SDK identity'
description: SDK identity system text sent by default.
sdkPackage: '@anthropic-ai/claude-agent-sdk@0.3.168'
claudeCodeVersion: '2.1.168'
-->
# System Block: SDK identity

## Metadata

- Request location: `system[1]`
- Type: `text`
- Cache control: `{"type":"ephemeral"}`

## Content

```text
You are a Claude agent, built on Anthropic's Claude Agent SDK.
```