Claude Fable 5.1 vs GPT-5.6 Sol
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 | GPT-5.6 Sol | Advantage |
|---|---|---|---|
| Capability | 73% | 60% | +13% (Claude Fable 5.1 leads) |
| Median task time | 1m 46s | 2m 50s | 1m 4s faster (Claude Fable 5.1 leads) |
| Approx. task cost | $0.026 / task | $0.039 / task | $0.013 / task lower (Claude Fable 5.1 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. GPT-5.6 Sol: 12.6% of ChatGPT Plus (75.5% / 5h, 12.6% / 1w) per run. Its weekly limit holds about 6 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.
| Dimension | Claude Fable 5.1 | GPT-5.6 Sol | Advantage |
|---|---|---|---|
| Capability | 74% | 74% | +1% (Claude Fable 5.1 leads) |
| Median task time | 6m 51s | 4m 46s | 2m 5s faster (GPT-5.6 Sol leads) |
| Approx. task cost | $0.051 / task | $0.033 / task | $0.018 / task lower (GPT-5.6 Sol 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. GPT-5.6 Sol: 2.9% of ChatGPT Plus (17.1% / 5h, 2.9% / 1w) per run. Its weekly limit holds about 6 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.
| Dimension | Claude Fable 5.1 | GPT-5.6 Sol | Advantage |
|---|---|---|---|
| Capability | 85% | 56% | +28% (Claude Fable 5.1 leads) |
| Median task time | 3m 48s | 6m 10s | 2m 22s faster (Claude Fable 5.1 leads) |
| Approx. task cost | $0.025 / task | $0.032 / task | $0.007 / 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. GPT-5.6 Sol: 0.7% of ChatGPT Plus (4.1% / 5h, 0.7% / 1w) per good solve. Its weekly limit holds about 6 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.
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 GPT-5.6 Sol?
Both clear tier 4 of 5, but Claude Fable 5.1 scores higher on capability: 73% versus 60% on real-world@v3, our private suite of real-world coding problems. Latest measurement 2026-09-01.
How much do Claude Fable 5.1 and GPT-5.6 Sol cost?
Claude Fable 5.1 runs on Claude Max 20x at $200/month (public price as of 2026-08-05). GPT-5.6 Sol runs on ChatGPT Plus at $20/month (public price as of 2026-07-20).