PydanticAI Tool System Tool Registration Two decorators based on whether you need context: Critical Rules 1. @agent.tool : First parameter MUST be 2. @agent.tool plain : MUST NOT have parameter 3. Docstrings : Required for LLM to understand tool purpose 4. Google-style docstrings : Used for parameter descriptions Gates (verify in the file, not from memory) 1. Decorator matches signature — If the first parameter is , the decorator must be (not ). Pass: the same line’s decorator stack includes , and the first parameter is typed . 2. Plain tools — With , the parameter list must not include . Pas…