Cursor Model Selection: Which AI for Which Coding Task

Cursor lets you choose between Claude, GPT-5, Gemini, Grok and its own in-house models. Picking the right one for each task is one of the highest-leverage skills for power users. Here is the complete guide.

One of Cursor's quiet advantages is that it is not locked to a single AI provider. You can use Anthropic's Claude, OpenAI's GPT models, Google's Gemini, xAI's Grok, and Cursor's own in-house models (Composer-1 for low-latency edits, Sonic for fast completions). Each has strengths, and matching the model to the task meaningfully affects both quality and cost.

Auto Mode vs Manual Selection

Cursor's default is Auto mode, which selects the best model for each task automatically. For most users this is the right choice: Cursor's routing logic is reasonably good, and Auto mode requests are unlimited on the Pro tier, meaning they do not draw from your credit pool. Manual selection lets you pick a specific model per request, which costs credits but gives you control when you know a particular model will perform better.

The Task-to-Model Map

Based on extensive testing reported by power users in 2026, clear patterns have emerged. For complex refactoring, Claude Sonnet or Opus excel because they best understand existing code patterns and intent. For algorithm design and novel problems, GPT-5 or Claude Opus offer the strongest reasoning. For quick Tab edits, Cursor's own Composer-1 wins on latency, being optimised specifically for inline editing.

For documentation, Claude Sonnet produces the most readable technical prose. For test generation, GPT-4o is strong at identifying edge cases. For quick, simple questions, Gemini Flash is the cheapest option with acceptable quality. For bug investigation across complex codebases, Claude Sonnet traces through code particularly well. For very long-context tasks, Gemini Pro offers the largest effective context window.

Cursor's In-House Models

Cursor trains its own models for tasks where its data and training process beat general-purpose frontier models. Composer-1 is optimised for low-latency multi-file edits, tuned specifically for the diff format Cursor uses, and Auto mode often selects it for routine Composer work. Sonic powers very fast Tab completions, where latency is critical, which is why most of your Tab interactions come from Sonic rather than a frontier model.

Understanding Credit Costs

Credit costs vary dramatically. The cheap tier (Composer-1, Sonic, Gemini Flash) costs roughly 0.05 to 0.15 credits per request. The medium tier (GPT-4o, Claude Sonnet, Gemini Pro) costs 0.30 to 0.80. The expensive tier (Claude Opus, GPT-5) costs 1.50 to 3.00 per request. Tab completions and Auto mode are unlimited and never burn credits.

The Optimisation Strategy

The pattern that keeps consumption sustainable while using the best model where it matters: use Auto mode for roughly 80% of your work, since it is unlimited on Pro. Switch to specific models manually only when you need their unique strengths, like Claude Opus for architectural decisions or GPT-5 for novel algorithm problems. This approach gives you frontier-model quality on the tasks that need it without burning through your credit pool on routine work.