Agent forgets the user's name after about 30 turns

My assistant agent greets the user by name at turn 1 and by turn 30 or so calls them "there". I am passing the whole conversation every time. Context is nowhere near the limit. What gives?

Long conversations dilute early facts. Two things work for us: put stable facts (name, preferences) in the system message rather than an early user turn, and summarise anything older than 20 turns into a short 'what we know' block.

Moved the name into the system prompt — fixed instantly. Embarrassingly simple.

Not embarrassing at all. 'Facts in system, history in messages' should be in the SDK README.