>I've never seen much difference with context ostensibly being shorter in GHCP, all of the models (in any provider) lose the thread well before their window is full, and it seems that aggressive autocompaction is a pretty standard way to help with that, and CC/Codex do it frequently.

Then we've had wildly different results. Running CC and GH copilot with Opus 4.6 on same task and the results out of CC were just better, likewise for Codex and GPT 5.4. I have to assume it's the aggressive context compaction/limited context loading because tracking what copilot does it seems to read way less context and then misses out on stuff other agents pick up automatically.