Delved into Cursor 3.0 -- turns out there's some interesting shenanigans going on....
"The most newsworthy finding is that "Cursor Agent" is a rebranded Claude Code running behind a local proxy with a find-and-replace engine that swaps "Claude"→"Cursor" in system prompts and messages.
They bundle the full
@anthropic-ai/claude-agent-sdk and
@anthropic-ai/claude-code packages, plus a custom fine-tuned model (claude-3.7-sonnet-finetuned-cursor-20250514-v1)"
Full report