Skip to content
Cursor Handbook

Opus, Fable and Sonnet in Cursor

Anthropic ships three tiers into Cursor's Other Models pool. The choice between them matters less than the reasoning effort you set, which is the variable most comparisons ignore.

  • Other Models pool
  • Three Anthropic tiers
  • Effort dominates cost

Checked against cursor.com on 25 September 2026

The variable everyone skips

Pick any two Anthropic models and the gap between them is smaller than the gap between one model at minimum effort and the same model at maximum. That single fact reframes the whole question.

On Cursor's own benchmark, Opus 5.5 Low scores 43.7 percent at $1.17 a task. Opus 5.5 Max scores 57.8 percent at $13.43. Same weights, same training, 14.1 points apart, and roughly 11 times the money.

So "which model" is the second question. The first is how hard you are asking it to think.

Where the returns stop

The Opus 5.5 rows are unusually instructive because High and Extra High land on the same score. Cost does not: Extra High costs roughly 1.8 times what High does for a result the benchmark cannot distinguish.

That is what a saturated dial looks like. Past a certain point, more thinking produces longer transcripts rather than better answers, and the extra steps are the model second-guessing itself. High is the sensible ceiling for routine work; Max is for the specific task that has already defeated everything else.

When the heavier model actually earns it

Three situations, and they share a shape: the cost of a wrong answer is high and the problem is genuinely underspecified.

  • Ambiguous multi-file refactors. Where the right change depends on reading intent across several files rather than applying a rule. This is precisely what CursorBench measures, which is why the ordering there is worth trusting for this case specifically.
  • A bug that survived two attempts. If a lighter model has already failed twice, a third attempt from it is unlikely to differ. The escalation is cheaper than your time.
  • Design decisions you will live with. Choosing an abstraction, a schema, a migration strategy. The token cost is trivial against the cost of unwinding it in three months.

Everything else, meaning the large majority of agent turns, is a rename, an import fix, a test stub or a file lookup. Paying frontier rates for those is how an allowance disappears by the middle of the month.

The practical pattern

Leave the picker on Auto, which draws from the cheaper Cursor Models pool entirely. When a task resists, switch to an Anthropic model at a middle effort for that task, then switch back. Escalating per task rather than per month is the difference between a Pro plan that lasts and one that does not.

Model list from the models and pricing table, scores from CursorBench, read on 25 September 2026. Benchmarks move; check both before making a spending decision.

Opus 5.5 across effort levels

One model, five configurations. The score barely moves across the top three while the cost multiplies.

Opus 5.5 CursorBench results by effort
ConfigurationScoreCost / taskSteps
Opus 5.5 Max57.8%$13.43185
Opus 5.5 Extra High56%$6.98109
Opus 5.5 High56%$3.9768
Opus 5.5 Medium52.5%$2.9154
Opus 5.5 Low43.7%$1.1728

Fable 5.1 across effort levels

The mid-weight line. Note that Fable at maximum effort costs more per task than Opus at maximum effort while scoring lower, which is the clearest argument against turning the dial up on a lighter model.

Fable 5.1 CursorBench results by effort
ConfigurationScoreCost / taskSteps
Fable 5.1 Max51.8%$17.28128
Fable 5.1 Extra High51.6%$13.01101
Fable 5.1 High49.2%$9.0877
Fable 5.1 Medium46.8%$7.0563
Fable 5.1 Low45.1%$5.4451

Frequently asked questions

Is Sonnet still available in Cursor?
Yes. Cursor's models table lists three Anthropic models in the Other Models pool: Claude Opus 5.5, Claude Fable 5.1 and Claude Sonnet 5. Fable is the newer mid-weight line and sits between the other two in Cursor's ordering.
Should I use Opus or Sonnet in Cursor?
Default to the lighter model and escalate. Most agent turns are edits, renames and lookups where the heavier model produces the same answer for several times the cost. Escalate when a task is genuinely ambiguous, spans many files, or has already failed twice.
How much more expensive is Opus than the lighter Anthropic models?
It depends far more on reasoning effort than on the model name. On CursorBench 4.0, Opus 5.5 Max costs an average $13.43 per task while Opus 5.5 Low costs $1.17: the same model, roughly 11 times the price, 14.1 points apart.
Is Opus worth it for coding in Cursor?
At a sensible effort level, often yes. Opus 5.5 High scores 56 percent for $3.97 a task, which is within 1.8 points of the top of the leaderboard at about a third of the cost. At maximum effort the value case is much weaker.
Do Anthropic models draw from my included usage?
They draw from the Other Models pool, which is separate from the generous Cursor Models pool covering Grok and Composer. That is why a month spent on Anthropic models depletes an allowance far faster than the same month on Auto.
Does Cursor's Auto ever pick an Anthropic model?
Auto routes within the Cursor Models pool, which is Grok and Composer. On Teams and Enterprise plans, Cursor Router can route to third-party models according to the optimisation mode, and those requests bill at the model's list price plus the Cursor Token Rate.
Which reasoning effort should I start with?
The middle. The leaderboard shows Opus 5.5 at High and Extra High scoring identically while cost nearly doubles, which means the top settings buy more thinking rather than more correctness. Start in the middle and move up only for a specific task that failed.