2 min lesson
Two groups of models, two jobs
Use "Two groups of models, two jobs" to tell the cases apart, then choose a response for each one.
Step 1 of 2
Two groups of models, two jobsmatch the model to the task
Before you can reason about which model is best, sort them by what they're for. The cleanest mental model splits the field into two groups. One group is async and high-reasoning - highly intelligent, strong at long-horizon work, more costly - the models you reach for when you're planning, auditing or running plan mode. The other group is fast synchronous executors: near-frontier intelligence at much higher speed, the implementers that do the work once a plan exists.
One is an async and high reasoning group. The next group are fast and synchronous workers. These are like the executors. They're like the implementers.
Strong reasoning, excellent at long-horizon tasks, more costly per token.
Reach for planning, plan mode and auditing - the GPT-5.x line and the current frontier Claude Opus (today Opus 5) sit here.
Near-frontier intelligence at much higher speed - the implementers.
Cursor's in-house ComposerCursor's own fast coding model, tuned for the editor and priced well below frontier models; the recommended day-to-day model for executing a plan. Press Enter for the full definition. models (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. / 2.5) live here; fast and reliable at medium-difficulty work, with frontier fast variants for documentation.
Interactive widget. Tab through its controls; the result updates in the panel below as you change them.
Sort by job first - reasoning for planning, fast executor for implementation - then let Auto mode route per task when you don't want to choose.