01-agent-loop

01: The Agent Loop — The 17-Line Agent

Key Insight: An AI coding agent is just a loop that lets a model call tools.

What You'll Learn

• The agent loop — the pattern behind every AI coding agent
• That one tool (bash) is enough for full capability
• How simple the "magic" behind Claude Code, Cursor, etc. really is

Prerequisites

• Python 3.10+ installed
• Anthropic API key configured in .env
• make install completed

How to Run

make 01-agent-loop
# or
uv run python 01-agent-loop/agent.py

What to Observe

1. The loop — the agent keeps calling bash until it decides the task is done
2. The model decides — you don't tell it which commands to run, it figures it out
3. One tool is enough — bash gives access to everything: files, search, execution

Key Concept

User → Model → [bash → result]* → Response
                  ^____________|

The asterisk (*) means "repeat until done." That's the whole secret.

Files

File	Lines	Description
agent.py	~130 lines (17-line core loop)	The complete agent

Next Module

Ready for more? → 02: Bash Agent