Roles and the system message

Three roles

Each message has a role. There are three roles.

Role	Who writes it	What it is for
system	You, the developer.	Instructions that stay the same for every call: the job, the rules, and the form of the answer.
user	The person who uses your program, or your program.	The text for this call: a question, or the data to work on.
assistant	The model.	An answer that the model gave before. Lesson 5 uses it.

A system message is always the first message of the list.

RULES = "Summarize the text in 8 words."
comment = "The dock at Town Hall was full."

messages = [
    {"role": "system", "content": RULES},
    {"role": "user", "content": comment},
]

Why two messages

You can put the instructions and the data in one user message, as you did in lesson 1. Two messages are better for a program.

• The instructions are in one place. You write them one time, and each call uses them.
• The data stays data. Your program puts the comment of a rider in the user message, and it does not mix the comment with your instructions.
• You can change the instructions and test them without a change to the rest of the program.

Say what you want

A model does what the messages say, and nothing tells it what you have in your head. If you send only a comment, the model does not know that you want a label. If you ask for a label but not for the form, you get a full sentence. A program cannot work with a sentence as well as with one word.

Compare these instructions. The answers are those of the simulated model of this course.

Instructions	Answer
Classify the comment.	I think this comment is a complaint. It has the word "full".
Classify the comment as one of: praise, complaint, question, other. Answer with one word.	complaint

The second form names the allowed labels and the form of the answer. Your code can compare the answer with a label directly.

Your turn

main.py has four comments of riders. Do the tasks in order.