Claude Fable 5 vs GPT-6 Astra
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 | GPT-6 Astra | Advantage |
|---|---|---|---|
| Capability | 60% | 57% | +3% (Claude Fable 5 leads) |
| Median task time | 2m 37s | 1m 56s | 40s faster (GPT-6 Astra leads) |
| Approx. task cost | $0.030 / task | $0.046 / task | $0.016 / task lower (Claude Fable 5 leads) |
Claude Fable 5: 33.0% of Claude Max 20x (33.0% / 5h, 5.0% / 1w) per run. Its weekly limit holds about 7.2 of the week's 33.6 5h windows. GPT-6 Astra: 3.0% of ChatGPT Pro $100 (3.0% / 1w) per run. Each figure is a share of that agent's own plan, so there is no delta to draw.
| Dimension | Claude Fable 5 | GPT-6 Astra | Advantage |
|---|---|---|---|
| Capability | 63% | 74% | +11% (GPT-6 Astra leads) |
| Median task time | 5m 32s | 4m 0s | 1m 32s faster (GPT-6 Astra leads) |
| Approx. task cost | $0.034 / task | $0.057 / task | $0.023 / task lower (Claude Fable 5 leads) |
Claude Fable 5: 10.0% of Claude Max 20x (10.0% / 5h, 2.0% / 1w) per run. Its weekly limit holds about 7.2 of the week's 33.6 5h windows. GPT-6 Astra: 1.0% of ChatGPT Pro $100 (1.0% / 1w) per run. Each figure is a share of that agent's own plan, so there is no delta to draw.
| Dimension | Claude Fable 5 | GPT-6 Astra | Advantage |
|---|---|---|---|
| Capability | 74% | 61% | +13% (Claude Fable 5 leads) |
| Median task time | 5m 28s | 2m 54s | 2m 35s faster (GPT-6 Astra leads) |
| Approx. task cost | $0.038 / task | $0.046 / task | $0.008 / task lower (Claude Fable 5 leads) |
Claude Fable 5: 2.8% of Claude Max 20x (2.8% / 5h, 0.4% / 1w) per good solve. Its weekly limit holds about 7.2 of the week's 33.6 5h windows. GPT-6 Astra: 0.2% of ChatGPT Pro $100 (0.2% / 1w) per good solve. 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 or GPT-6 Astra?
Claude Fable 5 clears higher: tier 4 of 5 versus tier 2 for GPT-6 Astra on real-world@v3, our private suite of real-world coding problems. Latest measurement 2026-08-30.
How much do Claude Fable 5 and GPT-6 Astra cost?
Claude Fable 5 runs on Claude Max 20x at $200/month (public price as of 2026-08-05). GPT-6 Astra runs on ChatGPT Pro $100 at $100/month (public price as of 2026-09-05).