Your first hand-written tool

So far you've seen tool schemas from the consumer side. what the model receives. Now you're going to write one.

Forge needs a simple tool: given a crewmate's alias, return their info. Your job: write the JSON Schema that defines that tool.

What it must carry

A valid tool schema has three non-negotiable fields:

1. name. unique identifier for the tool. Snake case, descriptive.
2. description. text the model READS to decide when to invoke it. This is the most important part. If the description is vague, the model won't use the tool. or will use it when it shouldn't.
3. parameters. JSON Schema describing the inputs. Each parameter carries a type, a description, and is marked as required if the tool doesn't work without it.

The starter

We give you the skeleton on the right. Your job:

• Fill in the description (min 20 chars, actionable).
• Define the alias parameter as string with its own description.
• Mark alias as required.

The tool description is the equivalent of the role in a prompt: it defines when the tool enters the picture. If the description doesn't mention the use case, the model won't know to pick it.

How it's evaluated

5 deterministic criteria (valid JSON, correct name, description with min length, alias parameter defined, alias in required) + 1 llm-judge on the description's clarity.