Claude Fable 5 vs GPT-6 Sol
Claude Fable 5 was superseded by Claude Fable 5.1. GPT-6 Sol was superseded by GPT-6.1 Sol. The grades below are the last ones measured, so read them as history rather than as this week's board. See the current roster.
Claude Fable 5 leads overall, C to C-. GPT-6 Sol is about 10x cheaper per task. By suite, real-world issues is even at C- and Claude Fable 5 takes spec planning (C to C-). Take GPT-6 Sol 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: GPT-6 Sol vs Claude Fable 5
Claude Fable 5 leads overall, C to C-. By suite: real-world issues is even at C- (60% vs 55% capability); Claude Fable 5 takes spec planning, C to C- (63% vs 60% capability); Claude Fable 5 takes vibe coding, C+ to C- (74% vs 61% capability). Claude Fable 5 used 7% of Claude Max 20x's weekly limit per pass, $0.169 per task at the listed price; at the ~$100 tier the board defaults to that is an estimated ~14% of Claude Max 5x's weekly limit (est, about $0.169 per task). GPT-6 Sol used 7% of ChatGPT Plus's weekly limit per pass, $0.017 per task at the listed price; at the ~$100 tier the board defaults to that is an estimated ~1.4% of ChatGPT Pro 5x's weekly limit (est, about $0.017 per task). Per task, GPT-6 Sol is about 10x cheaper ($0.017 vs $0.169). GPT-6 Sol is faster on real-world issues: a median task takes 1m 41s against 2m 37s. Both finished every task on it. Reasons to pick GPT-6 Sol anyway: it is cheaper per task ($0.017 vs $0.169) and it is faster on real-world issues (1m 41s vs 2m 37s median).
Changed since the previous graded week: Claude Fable 5: real-world issues C+ to C-, vibe coding C to C+; GPT-6 Sol: real-world issues D- to C-, real-world issues usage 4% to 5% of the weekly limit, spec planning C to C-, spec planning usage 1% to 2% of the weekly limit, vibe coding D+ to C-.
| Dimension | Claude Fable 5 | GPT-6 Sol | Advantage |
|---|---|---|---|
| Capability | 60% | 55% | +5% (Claude Fable 5 leads) |
| Median task time | 2m 37s | 1m 41s | 56s faster (GPT-6 Sol leads) |
| Approx. task cost | $0.153 / task | $0.015 / task | $0.138 / task lower (GPT-6 Sol leads) |
Claude Fable 5: 33.0% of Claude Max 20x (33.0% / 5h, 5.0% / 1w) per run. Its weekly limit holds about 7 of the week's 33.6 5h windows. GPT-6 Sol: 5.0% of ChatGPT Plus (35.0% / 5h, 5.0% / 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 | GPT-6 Sol | Advantage |
|---|---|---|---|
| Capability | 63% | 60% | +3% (Claude Fable 5 leads) |
| Median task time | 5m 32s | 2m 58s | 2m 34s faster (GPT-6 Sol leads) |
| Approx. task cost | $0.230 / task | $0.023 / task | $0.207 / task lower (GPT-6 Sol leads) |
Claude Fable 5: 10.0% of Claude Max 20x (10.0% / 5h, 2.0% / 1w) per run. Its weekly limit holds about 7 of the week's 33.6 5h windows. GPT-6 Sol: 2.0% of ChatGPT Plus (10.0% / 5h, 2.0% / 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 | GPT-6 Sol | Advantage |
|---|---|---|---|
| Capability | 74% | 61% | +13% (Claude Fable 5 leads) |
| Median task time | 5m 28s | 2m 44s | 2m 44s faster (GPT-6 Sol leads) |
| Approx. task cost | $0.184 / task | $0.018 / task | $0.166 / task lower (GPT-6 Sol 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 of the week's 33.6 5h windows. GPT-6 Sol: 0.4% of ChatGPT Plus (1.8% / 5h, 0.4% / 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 or GPT-6 Sol?
Claude Fable 5 clears higher: tier 4 of 5 versus tier 1 for GPT-6 Sol on real-world@v3, our private suite of real-world coding problems. Latest measurement 2026-08-30.
Which is cheaper per task, Claude Fable 5 or GPT-6 Sol?
Claude Fable 5 used 7% of Claude Max 20x's weekly limit per pass, $0.169 per task at the listed price; at the ~$100 tier the board defaults to that is an estimated ~14% of Claude Max 5x's weekly limit (est, about $0.169 per task). GPT-6 Sol used 7% of ChatGPT Plus's weekly limit per pass, $0.017 per task at the listed price; at the ~$100 tier the board defaults to that is an estimated ~1.4% of ChatGPT Pro 5x's weekly limit (est, about $0.017 per task). Per task, GPT-6 Sol is about 10x cheaper ($0.017 vs $0.169).
What do Claude Fable 5 and GPT-6 Sol cost a month?
Claude Fable 5 runs on Claude Max 20x at $200/month (public price as of 2026-08-05). GPT-6 Sol runs on ChatGPT Plus at $20/month (public price as of 2026-07-20).