L1: Your First Agent

Build a single-tool agent from scratch.

Module: M1 Foundations
Est. Time: 60 min
Files: starter.py, solution.py

Objective

Create an agent that reads a file and answers questions about its contents.

Concepts

• LLM + Tools + Loop = Agent
• Tool definition with input schema
• The agent loop (think → act → observe → repeat)
• The reasoning parameter

Starter

cd course/labs/L1-first-agent/
python starter.py test.txt "What is this file about?"

The starter has TODO markers where you fill in:

1. Define the read_file tool schema
2. Implement the execute_tool function
3. Implement the run_agent loop
4. Wire up the main entry point

Solution

python solution.py test.txt "What is this file about?"

Compare your implementation against the solution. Key differences to check:

• Did you set MAX_ITERATIONS?
• Does every tool call include reasoning?
• Does the loop terminate on end_turn?

Checkpoints

1. Tool call is made correctly (schema matches)
2. Tool result is fed back to the LLM
3. LLM produces final answer using tool result
4. Loop terminates (doesn't run forever)