M4 solution

The expected, fully-commented artifacts for M4's lab. Peek only after you've tried the lab.

File	What it is
check_setup.py	The smallest possible call, loads .env, validates the key, makes one tiny request. Run this first.
chatbot.py	The minimal chatbot: a system personality, a running messages list, and a loop that remembers the conversation.
.env.example	Template for your secret key. Copy to .env (which is git-ignored) and paste your real key. Never commit .env.

Run it

On your own machine, with your virtual environment active and your key in .env:

pip install anthropic python-dotenv     # once (or: pip install -r ../../requirements.txt)
python check_setup.py                   # confirm the key works
python chatbot.py                       # chat (type 'quit' to leave)

How this was verified

Everything except the live billed call was verified on Python 3 with anthropic 0.109.2 and python-dotenv in a fresh virtual environment: - all three files compile; - python-dotenv loads a placeholder key from .env and anthropic.Anthropic() constructs against it; - the chatbot loop was exercised end-to-end with the API mocked: it sends model, system, and the growing messages list, reads response.content[0].text, and appends the reply so the bot remembers.

The single thing only a real key can confirm is the live response text, that's the learner's Step 6 (check_setup.py), and it's the one item flagged for a human pilot. No real API key or billed call was used in preparing this module.