What they are for
Context the next colleague needs and the customer should not see. What has been tried, what has been ruled out, what is agreed, what remains unknown, and any commercial background that changes how the case should be handled.
The rule that keeps them safe
Assume every note will one day be read aloud — in a dispute, in a data-subject access request, or by a new colleague who repeats it to the customer by accident. Write nothing you would not defend in that room.
A good note and a bad note
Bad: “Difficult customer, third time this week, ignore.”
Good: “Third contact this week on the same fault. Replaced the unit on the 4th; issue recurred. Escalating to engineering rather than repeating the swap.”
The second is more useful, entirely defensible, and takes the same time to write.
Making it a habit
Include note quality in your QA rubric. Agents write good notes when notes are read, and notes are read when the team has been burned once by their absence.