Originally published at heyuan110.com
On March 19, Cursor shipped Composer 2 with a triumphant blog post. Three days later, a developer found kimi-k2p5-rl-0317-s515-fast in the API config. That single string unraveled a story about transparency, open-source ethics, and the global nature of AI infrastructure.
Key findings:
- Composer 2 is built on Moonshot AI's Kimi K2.5 (Chinese open-source MoE model)
- Cursor's "75% of compute was ours" defense doesn't hold up
- CursorBench scores (61.3) are home-field advantage; Terminal-Bench gap vs Claude is only 3.7 points
- At $0.50/M input tokens, Composer 2 is 30x cheaper than Opus 4.6
- Most productive devs use both: Cursor for 80% daily tasks, Claude Code for 20% complex work
If you found this useful, check out my blog for more AI engineering guides.
Top comments (0)