A Tool Is Like a Button on a Remote
Ideally a tool you give an Agent is like a button on a remote: you can tell what it does at a glance, and pressing it does just one thing.
Single Responsibility: One Tool Does One Thing
Don't build a "Swiss Army knife" tool. Cram too many functions into one tool and the model struggles to tell when to use it and how to fill in the parameters.
# 不好：一个工具啥都干
def handle_user(action, data): ...
# 好：拆成单一职责
def get_user(user_id: str) -> dict:
"""按用户 ID 查询用户资料。"""
...
def update_user_email(user_id: str, email: str) -> bool:
"""更新指定用户的邮箱。"""
...The Description Is the Manual the Model Reads
The model decides when to call a tool based on its name + description. Write the description clearly and call accuracy jumps right up.
def send_invoice(order_id: str) -> str:
"""给指定订单生成并发送发票。仅在用户明确要发票时调用。"""
...自测 · 学完检查一下
想真正动手做题、记进度、攒连胜？到互动课里练。
What's the benefit of a "single-responsibility" tool?
答案：Clearer purpose and parameters, so the model picks better
A tool that does just one thing makes it easier for the model to judge when to use it and how to fill in the parameters.
Judge: stuffing multiple functions into one "all-purpose tool" helps the model use it more accurately.
答案：False
Piling functions together actually makes it harder for the model to judge when to use it and how to fill in parameters—split into single responsibilities.
Judge: is the tool below well designed?
def do(t, v):
return run(t, v)答案：Not well
The name `do` and parameters `t`/`v` reveal no meaning, and there's no description—the model has no basis to judge when to call it.
Which tool definition best meets the standard of a "good tool"?
答案：def get_order_status(order_id: str) -> str: Query the current status of a given order.
A clear name, single responsibility, meaningful parameters, and a description that states the purpose—that's a good tool.
The model mainly relies on a tool's name and ___ to decide when to call it.
答案：description
Name plus description is the manual the model reads; write it clearly and it calls accurately.
Judge: if a vague tool description leads to misuse, the problem is mainly in the tool design, not the model.
答案：True
The description is the manual for the model; if the manual is vague, the fault for a wrong call lies with the designer.