Claude Fable 5.1 vs Composer 2.5
Claude Fable 5.1 leads overall, B- to D. Composer 2.5 is about 4.5x cheaper per task. By suite, Claude Fable 5.1 takes real-world issues (B+ to C-) and spec planning (C+ to D). Take Composer 2.5 anyway when you want the side that is cheaper per task and faster on real-world issues.Measured
Each agent graded on the same private suites, running headless through its own tools. Advantages are oriented so a win is a win, whichever way the metric runs.
Verdict: Composer 2.5 vs Claude Fable 5.1
Claude Fable 5.1 leads overall, B- to D. By suite: Claude Fable 5.1 takes real-world issues, B+ to C- (87% vs 57% capability); Claude Fable 5.1 takes spec planning, C+ to D (71% vs 48% capability); Claude Fable 5.1 takes vibe coding, C+ to F (74% vs 23% capability). Claude Fable 5.1 used 8% of Claude Max 5x's weekly limit per pass, $0.097 per task at the listed price. Composer 2.5 used 2.0% of Cursor Pro's monthly limit per pass, $0.021 per task at the listed price. Per task, Composer 2.5 is about 4.5x cheaper ($0.021 vs $0.097). Composer 2.5 is faster on real-world issues: a median task takes 1m 34s against 3m 38s. Both finished every task on it. Reasons to pick Composer 2.5 anyway: it is cheaper per task ($0.021 vs $0.097) and it is faster on real-world issues (1m 34s vs 3m 38s median).
Changed since W39: Claude Fable 5.1: real-world issues D+ to B+, real-world issues usage 7% to 5% of the weekly limit, spec planning usage 4% to 3% of the weekly limit, vibe coding C- to C+, vibe coding usage 0.6% to 0.4% of the weekly limit; Composer 2.5: real-world issues D+ to C-.
| Dimension | Claude Fable 5.1 | Composer 2.5 | Advantage |
|---|---|---|---|
| Capability | 87% | 57% | +30% (Claude Fable 5.1 leads) |
| Median task time | 3m 38s | 1m 34s | 2m 3s faster (Composer 2.5 leads) |
| Approx. task cost | $0.077 / task | $0.021 / task | $0.056 / task lower (Composer 2.5 leads) |
Claude Fable 5.1: 64.0% of Claude Max 5x (64.0% / 5h, 5.0% / 1w) per run. Its weekly limit holds about 13.8 of the week's 33.6 5h windows. Composer 2.5: 1.6% of Cursor Pro (1.6% / 1m) per run. Each figure is a share of that agent's own plan, so there is no delta to draw.
Work per window: Claude Fable 5.1 228 vs Composer 2.5 63 suite runs per month (Claude Fable 5.1 leads); per plan-dollar: 2.28 vs 3.15 (Composer 2.5 leads). Work figures compare outputs, so unlike quota shares they are comparable across plans.
| Dimension | Claude Fable 5.1 | Composer 2.5 | Advantage |
|---|---|---|---|
| Capability | 71% | 48% | +23% (Claude Fable 5.1 leads) |
| Median task time | 8m 55s | 1m 8s | 7m 47s faster (Composer 2.5 leads) |
| Approx. task cost | $0.172 / task | $0.022 / task | $0.150 / task lower (Composer 2.5 leads) |
Claude Fable 5.1: 33.0% of Claude Max 5x (33.0% / 5h, 3.0% / 1w) per run. Its weekly limit holds about 13.8 of the week's 33.6 5h windows. Composer 2.5: 0.4% of Cursor Pro (0.4% / 1m) per run. Each figure is a share of that agent's own plan, so there is no delta to draw.
Work per window: Claude Fable 5.1 443 vs Composer 2.5 225 suite runs per month (Claude Fable 5.1 leads); per plan-dollar: 4.43 vs 11.23 (Composer 2.5 leads). Work figures compare outputs, so unlike quota shares they are comparable across plans.
| Dimension | Claude Fable 5.1 | Composer 2.5 | Advantage |
|---|---|---|---|
| Capability | 74% | 23% | +52% (Claude Fable 5.1 leads) |
| Median task time | 4m 14s | 1m 37s | 2m 37s faster (Composer 2.5 leads) |
| Approx. task cost | $0.092 / task | $0.022 / task | $0.070 / task lower (Composer 2.5 leads) |
Claude Fable 5.1: 4.2% of Claude Max 5x (4.2% / 5h, 0.4% / 1w) per good solve. Its weekly limit holds about 13.8 of the week's 33.6 5h windows. Composer 2.5: 0.1% of Cursor Pro (0.1% / 1m) per good solve. Each figure is a share of that agent's own plan, so there is no delta to draw.
Work per window: Claude Fable 5.1 3479 vs Composer 2.5 920 good solves per month (Claude Fable 5.1 leads); per plan-dollar: 34.79 vs 46.02 (Composer 2.5 leads). Work figures compare outputs, so unlike quota shares they are comparable across plans.
Grades and deltas are comparable only within a suite version. See methodology.
Frequently asked questions
Which is better for coding, Claude Fable 5.1 or Composer 2.5?
Claude Fable 5.1 clears higher: tier 4 of 5 versus tier 1 for Composer 2.5 on real-world@v3, our private suite of real-world coding problems. Latest measurement 2026-09-27.
Which is cheaper per task, Claude Fable 5.1 or Composer 2.5?
Claude Fable 5.1 used 8% of Claude Max 5x's weekly limit per pass, $0.097 per task at the listed price. Composer 2.5 used 2.0% of Cursor Pro's monthly limit per pass, $0.021 per task at the listed price. Per task, Composer 2.5 is about 4.5x cheaper ($0.021 vs $0.097).
Which gives more coding work per dollar, Claude Fable 5.1 or Composer 2.5?
Composer 2.5 delivers more benchmark work per subscription dollar: 3.15 suite runs per plan-dollar versus 2.28 for Claude Fable 5.1 (at $20/month priced 2026-07-20, and $100/month priced 2026-07-27). Work figures compare outputs, so unlike raw quota shares they are comparable across plans.
What do Claude Fable 5.1 and Composer 2.5 cost a month?
Claude Fable 5.1 runs on Claude Max 5x at $100/month (public price as of 2026-07-27). Composer 2.5 runs on Cursor Pro at $20/month (public price as of 2026-07-20).