Cursor unveils Composer 2

A developer debugging Cursor’s OpenAI-compatible endpoint captured the internal model identifier accounts/anysphere/models/kimi-k2p5-rl-0317-s515-fast and posted it publicly on March 19, 2026. (analyticsindiamag.com) Moonshot AI’s pretraining lead posted that Composer 2’s tokenizer matched Moonshot’s tokenizer and questioned license compliance before deleting the post and raising the issue on social media. (kucoin.com) Moonshot later posted a public endorsement that its Kimi family “provided the foundation” for the product and congratulated the Cursor team, while noting the integration ran through a commercial inference channel. (analyticsindiamag.com) Cursor cofounder Aman Sanger acknowledged in a March 21 post that the company “missed” naming the base model in its launch blog and said Cursor will correct attribution in future releases. (economictimes.indiatimes.com) Cursor published per‑token pricing at $0.50 per million input tokens and $2.50 per million output tokens and reported benchmark scores including 61.3 on CursorBench, 61.7 on Terminal Bench 2.0, and 73.7 on SWE‑Bench Multilingual. (economictimes.indiatimes.com) Composer 2 is described in company materials as supporting agentic workflows with multi-file edits, terminal operations and a context window on the order of 200,000 tokens. (analyticsindiamag.com) Cursor’s deployment pipeline routes model inference and reinforcement‑learning fine‑tuning through Fireworks AI’s hosted infrastructure as part of the commercial setup cited by both Cursor and third‑party observers. (analyticsindiamag.com) Independent writeups characterise the public record on provenance as community forensics—client traces, output fingerprints and deleted social posts—without a single authoritative, independently verifiable disclosure of the full training lineage. (novaknown.com)