Module 04 Summary

What this module established

Tools handed to an agent are capabilities handed to a model, so make misuse impossible rather than discouraged: read-only where you can, self-validating always, never raising. A refusal string teaches the agent something; an exception teaches it nothing and kills the task.

Carry forward

• Scope tools per agent. A capability the agent does not have is a guarantee; one it is told not to use is a hope.
• Give each knowledge source a staleness budget from how often it changes. Retrieval has no opinion about time.
• Most reported memory failures are facts never extracted into fields, not facts stored and lost.
• Test tools directly with .run() - it is the only part of a crew where testing is free, deterministic and exhaustive.

Before moving on

Move on when every refusal branch has a direct test, exactly one agent holds write access, and each knowledge source has a justified staleness budget.

Mark complete