GPT 5.5 seems to be degraded

Context comes from a dozen places other than your current thread, so “fairly new convo” is irrelevant. Each and every skill you have installed, your agents.md , each and every MCP you have install, your memories if you have them, your git commits, etc etc… Try using GPT 5.5 via the api with zero context and you will see that this issue is caused by your usage and not GPT 5.5 suddenly not working as well. Its a user issue of course.