Week 1 extra: agent loop — bill split and tip

This folder is a Week 1 extra exercise solution (see 1_foundations/5_extra.ipynb): an agent loop built from scratch with todo tools and a safe calculate tool so arithmetic is done in code (not guessed by the model). The scenario (bill + tip + split) is intentionally simple so the notebook stays focused on demonstrating the agent loop—tool schemas, dispatch, todos, and the driver loop—without extra domain noise.

Problem

Given a restaurant bill, tip percentage, and number of people, the agent should report how much each person pays after tip, using the tools until the task is done.

Setup

• Complete the course setup so OPENAI_API_KEY is in your environment (or .env at the repo root).
• Optional: set OPENAI_MODEL (defaults to gpt-4o-mini in the notebook).

Run

Open 5_extra_bill_split_agent.ipynb in Jupyter or Cursor and run all cells. The last cells reset state and run one demo prompt.

Inspired by

1_foundations/5_extra.ipynb — same loop shape (tool schemas → handle_tool_calls → loop until no tool calls).

Next step

• Using the same setup but solving a problem worth using LLMs