Cursor Composer 2 Is Built on Open-Source Kimi K2.5

Melvin Vivas · X post · 2026-03-21 · Open on X

Topics: Industry Trends & Job Market, LLM Fundamentals, AI Dev Tools & Productivity · Level: beginner

Summary

The post says Cursor's Composer 2 coding model uses Moonshot's open-source Kimi K2.5 as its base model. It shows that commercial coding tools are building on open-weight models.

Key points

• Cursor Composer 2 is built on top of Kimi K2.5.
• Kimi K2.5 is an open-source model from Moonshot AI.
• Open-weight base models are now strong enough to power commercial coding agents.

Resources mentioned

• Kimi K2.5 · tool · huggingface.co · free
  An open-source large language model from Moonshot AI.
• Composer 2 · tool · cursor.com · paid
  Cursor's own frontier coding model, built for agentic coding with high limits and fast speeds.
  Also in: Which AI coding model to use for which task (Melvin Vivas on X · notes), Cursor 3: An Agent-First IDE for Local and Cloud Coding Agents (Melvin Vivas on X · notes), Cursor Releases Composer 2, Its Own Coding Model (Melvin Vivas on X · notes)