Claude Fable 5.1 vs Kimi K3 256K
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.
| Dimension | Claude Fable 5.1 | Kimi K3 256K | Advantage |
|---|---|---|---|
| Capability | 73% | 57% | +17% (Claude Fable 5.1 leads) |
| Median task time | 1m 46s | 3m 34s | 1m 48s faster (Claude Fable 5.1 leads) |
| Approx. task cost | $0.026 / task | $0.025 / task | $0.001 / task lower (Kimi K3 256K leads) |
Claude Fable 5.1: 28.0% of Claude Max 20x (28.0% / 5h, 5.0% / 1w) per run. Its weekly limit holds about 7.2 of the week's 33.6 5h windows. Kimi K3 256K: 140.0% of Kimi Allegretto (140.0% / 5h, 28.0% / 1w) per run. Its weekly limit holds about 5 of the week's 33.6 5h windows. Each figure is a share of that agent's own plan, so there is no delta to draw.
Work per window: Claude Fable 5.1 522 vs Kimi K3 256K 104 suite runs per month (Claude Fable 5.1 leads); per plan-dollar: 2.61 vs 2.68 (Kimi K3 256K leads). Work figures compare outputs, so unlike quota shares they are comparable across plans.
| Dimension | Claude Fable 5.1 | Kimi K3 256K | Advantage |
|---|---|---|---|
| Capability | 74% | 41% | +33% (Claude Fable 5.1 leads) |
| Median task time | 6m 51s | 6m 34s | 17s faster (Kimi K3 256K leads) |
| Approx. task cost | $0.051 / task | $0.031 / task | $0.021 / task lower (Kimi K3 256K leads) |
Claude Fable 5.1: 15.0% of Claude Max 20x (15.0% / 5h, 2.0% / 1w) per run. Its weekly limit holds about 7.2 of the week's 33.6 5h windows. Kimi K3 256K: 46.0% of Kimi Allegretto (46.0% / 5h, 9.0% / 1w) per run. Its weekly limit holds about 5 of the week's 33.6 5h windows. Each figure is a share of that agent's own plan, so there is no delta to draw.
Work per window: Claude Fable 5.1 974 vs Kimi K3 256K 318 suite runs per month (Claude Fable 5.1 leads); per plan-dollar: 4.87 vs 8.14 (Kimi K3 256K leads). Work figures compare outputs, so unlike quota shares they are comparable across plans.
| Dimension | Claude Fable 5.1 | Kimi K3 256K | Advantage |
|---|---|---|---|
| Capability | 85% | 55% | +30% (Claude Fable 5.1 leads) |
| Median task time | 3m 48s | 6m 31s | 2m 43s faster (Claude Fable 5.1 leads) |
| Approx. task cost | $0.025 / task | $0.029 / task | $0.005 / task lower (Claude Fable 5.1 leads) |
Claude Fable 5.1: 1.8% of Claude Max 20x (1.8% / 5h, 0.2% / 1w) per good solve. Its weekly limit holds about 7.2 of the week's 33.6 5h windows. Kimi K3 256K: 11.0% of Kimi Allegretto (11.0% / 5h, 2.4% / 1w) per good solve. Its weekly limit holds about 5 of the week's 33.6 5h windows. 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 8117 vs Kimi K3 256K 1328 good solves per month (Claude Fable 5.1 leads); per plan-dollar: 40.58 vs 34.06 (Claude Fable 5.1 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 Kimi K3 256K?
Claude Fable 5.1 clears higher: tier 4 of 5 versus tier 2 for Kimi K3 256K on real-world@v3, our private suite of real-world coding problems. Latest measurement 2026-09-01.
Which gives more work per dollar, Claude Fable 5.1 or Kimi K3 256K?
Kimi K3 256K delivers more benchmark work per subscription dollar: 2.68 suite runs per plan-dollar versus 2.61 for Claude Fable 5.1 (at $39/month priced 2026-07-20, and $200/month priced 2026-08-05). Work figures compare outputs, so unlike raw quota shares they are comparable across plans.
How much do Claude Fable 5.1 and Kimi K3 256K cost?
Claude Fable 5.1 runs on Claude Max 20x at $200/month (public price as of 2026-08-05). Kimi K3 256K runs on Kimi Allegretto at $39/month (public price as of 2026-07-20).