So far it was words. Now come actions.

In the previous tracks you learned to make the model understand: structure prompts, sustain conversations, recover from bad outputs. All that is communication. But there's a huge class of problems where the answer isn't telling you something. it's doing something: looking a record up in a database, assigning a shift, sending a notification, querying inventory.

For that, the model needs tools.

A tool is a function the model can decide to invoke. You define what it does, what it's called, what inputs it accepts. The model decides when to use it based exclusively on what you wrote about it.

Forge is the crew's engineer. the one who builds the tools. In this track she'll teach you the three skills that separate an MCP the model uses from one it ignores:

1. Define the schema. what inputs it accepts and what it guarantees.
2. Write the description. when the model should pick it.
3. Implement the handler. what happens when it's invoked, including the edge cases.

You start in the next step. Forge has things she needs to automate, and you're going to build her the toolkit.