Mixing models: plan with one, build with another

Plan with one model, build with another

This is the callback that ties the engine dial to the posture dial. Plan mode (from the modes chapter), introduced with Cursor 2.0, lets you plan with one model and build with another - point a frontier reasoning model at the design, where a bad call is most expensive, then hand the approved, written-down plan to a faster, cheaper model to execute. Cursor’s 2.0 changelog frames it directly: create your plan with one model and build the plan with another, in the foreground or background, even planning with parallel agents to have multiple plans to review.

Read through the pricing guidance, that workflow is a cost strategy as much as a quality one. A stronger planner runs for the design, then a lower-cost model can do the bulk typing against a plan that’s already sitting in a markdown file. The exact billing treatment depends on your plan and current routing, so check the usage dashboard rather than assuming a fixed pool. That’s spend-where-it-pays expressed as a two-model loop: heavy reasoning where the fork is, efficient throughput where it’s just execution.

The skill, restated

The model picker isn’t a roster to memorise - the roster will have changed by the time you’ve memorised it. It’s a single dial with a meter attached, and the judgment is the same one this whole course keeps circling:

• Default to Auto. Auto routes routine work without forcing you to memorise the roster. Most of your day belongs here.
• Reach for Composer when you want Cursor’s own agentic model by name, then check its current plan and usage treatment.
• Pin a stronger model only when the reasoning genuinely pays. It may change usage and billing, so check the current pricing for your plan before relying on the pattern.
• Use MAX Mode when the bottleneck is how much the model can see at once - and check the current model and plan details because it can change billing.
• Split the loop when the stakes justify it: a frontier model to plan, a cheap one to build.

The person who’s merely installed Cursor pins their favourite model and pays for unnecessary capability to type out boilerplate. The person who’s good with it lets Auto carry the everyday and spends deliberately on the handful of turns where a stronger engine actually changes the answer.

Which model answers is one dial. What the model knows about budgetcli before it answers is another - and that one you control by writing it down once, in a file the agent reads on every turn. Next: writing rules down once.