Chapter 4: Tools and file system access

Goal of this chapter: add Tool capabilities so the Agent can access the file system.

Why Tools

In Chapters 1–3, the Agent can only chat; it cannot perform real actions.

Typical limitations without tools:

• Only generates text responses
• Cannot access external resources (files/APIs/databases)
• Cannot execute real tasks (compute/query/modify)

Code location

• Entry code: cmd/ch04/main.go

Full tutorial

• ch04_tool_backend_filesystem.md

What you learn

• How to expose file reads as tools and let the model call them through the Agent.
• How to keep tool boundaries explicit (inputs/outputs) so they are testable and observable.