2 min lesson
Post-training pipeline end to end
Explain the order in "Post-training pipeline end to end", then say how you would verify the result.
Step 1 of 2
A state-of-the-art coding agent isn't one training run. It's a pipeline where each stage constrains the next and Cursor research owns decisions across all of them - including which base model to even start from.
Cursor has published that Composer 2Cursor's in-house agentic coding model: frontier-level coding quality at high speed and low cost, built as a software-engineering specialist rather than a general-purpose model. Press Enter for the full definition. continued pretraining on a code-heavy mix before any preference work, which is a real, defensible choice you can speak to. Knowing the order of stages and what each one is good at, lets you reason about where a problem you're handed actually lives.
Interactive diagram. Step through it with the Next and Previous controls below, or Tab to a region to read its detail.
Each stage constrains the next; RL is the optimization gate where reward, not imitation, takes over.