Model comparison
Claude Fable 5 vs GPT-5.5 Pro
Head-to-head evidence from 1 shared benchmark result across 1 category. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: Claude Fable 5 #3 (Supported); GPT-5.5 Pro #41 (Estimated). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Claude Fable 5 and GPT-5.5 Pro share 1 comparable benchmark result. 1 of 8 categories are comparable. 33 results are unique to Claude Fable 5; 6 to GPT-5.5 Pro.
Updated July 24, 2026- Shared results
- 1
- Claude Fable 5 only
- 33
- GPT-5.5 Pro only
- 6
- Comparable categories
- 1 / 8
Pick Claude Fable 5 if you want the stronger benchmark profile. GPT-5.5 Pro only becomes the better choice if agentic is the priority.
Confidence note. This is a partial-evidence comparison with 1 shared benchmark result across 1 evidence category; 1 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.
Why this result
Claude Fable 5 is clearly ahead on the BenchAlign aggregate, 82.76 to 62.83. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
GPT-5.5 Pro is also the more expensive model on tokens at $30.00 input / $180.00 output per 1M tokens, versus $10.00 input / $50.00 output per 1M tokens for Claude Fable 5. That is roughly 3.6x on output cost alone. Claude Fable 5 gives you the larger context window at 1M+, compared with 1M for GPT-5.5 Pro.
Category breakdown
Exact category averages are shown below. Not measured means BenchLM does not have enough sourced public coverage for that model and category.
| Category | Claude Fable 5 | Δ | GPT-5.5 Pro |
|---|---|---|---|
| Agentic | Claude Fable 584.6 | Margin→ 5.5 | GPT-5.5 Pro90.1 |
| Coding | Claude Fable 589.2 | MarginNo overlap | GPT-5.5 ProNot measured |
| Knowledge | Claude Fable 5Not measured | MarginNo overlap | GPT-5.5 Pro57.2 |
| Math | Claude Fable 5Not measured | MarginNo overlap | GPT-5.5 Pro48.1 |
| Multimodal | Claude Fable 557.9 | MarginNo overlap | GPT-5.5 ProNot measured |
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | Claude Fable 5 | GPT-5.5 Pro | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Claude Fable 5$10 input / $50 output | GPT-5.5 Pro$30 input / $180 output | Claude Fable 5 has the lower combined listed price. |
| Generation speedtokens per second | Claude Fable 5Not available | GPT-5.5 ProNot available | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | Claude Fable 5Not available | GPT-5.5 ProNot available | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | Claude Fable 51M+ | GPT-5.5 Pro1M | Claude Fable 5 lists the larger context window. |
Benchmark Deep Dive
AgenticGPT-5.5 Pro wins14 benchmarks
| Benchmark | Claude Fable 5 | GPT-5.5 Pro | Result |
|---|---|---|---|
| Terminal-Bench 2.0Source | 84.3% | — | Not comparable |
| OSWorld-VerifiedSource | 85% | — | Not comparable |
| GDPval-AASource | 1747 | — | Not comparable |
| AA Agentic IndexSource | 52.8% | — | Not comparable |
| τ²-bench resultsSource | 98.5% | — | Not comparable |
| GDPval-AASource | 62.3% | — | Not comparable |
| AA BriefcaseSource | 1574 | — | Not comparable |
| AA AutomationBenchSource | 48.6% | — | Not comparable |
| AA EnterpriseOps-GymSource | 51.1% | — | Not comparable |
| AA Harvey LABSource | 93.6% | — | Not comparable |
| AA Tau3 BankingSource | 26.8% | — | Not comparable |
| terminalBenchHardSource | 62.9% | — | Not comparable |
| aaTerminalBench21Source | 84.6% | — | Not comparable |
| BrowseCompSource | — | 90.1% | Not comparable |
Coding9 benchmarks
| Benchmark | Claude Fable 5 | GPT-5.5 Pro | Result |
|---|---|---|---|
| SWE-bench VerifiedSource | 95% | — | Not comparable |
| SWE-bench ProSource | 80% | — | Not comparable |
| FrontierCode 1.1 MainSource | 53.5% | — | Not comparable |
| Terminal-Bench 2.0Source | 84.3% | — | Not comparable |
| cursorBench31Source | 70.6% | — | Not comparable |
| cursorBench32Source | 70.5% | — | Not comparable |
| VulcanBench v3Source | 87.0% | — | Not comparable |
| AA Coding IndexSource | 76.5% | — | Not comparable |
| AA-SciCodeSource | 60.2% | — | Not comparable |
Reasoning2 benchmarks
Knowledge8 benchmarks
| Benchmark | Claude Fable 5 | GPT-5.5 Pro | Result |
|---|---|---|---|
| Artificial Analysis Intelligence IndexSource | 59.9% | — | Not comparable |
| AA-GPQA DiamondSource | 92.6% | — | Not comparable |
| AA-HLESource | 53.3% | — | Not comparable |
| AA-Omniscience IndexSource | 40.2% | — | Not comparable |
| AA-Omniscience AccuracySource | 61.4% | — | Not comparable |
| AA-Omniscience Hallucination RateSource | 54.9% | — | Not comparable |
| HLESource | — | 57.2% | Not comparable |
| HLE w/o toolsSource | — | 43.1% | Not comparable |
Math3 benchmarks
Multimodal3 benchmarks
Inst. Following1 benchmarks
| Benchmark | Claude Fable 5 | GPT-5.5 Pro | Result |
|---|---|---|---|
| AA-IFBenchSource | 63.5% | — | Not comparable |
Frequently Asked Questions (2)
Which is better, Claude Fable 5 or GPT-5.5 Pro?
Claude Fable 5 is ahead on BenchLM's BenchAlign leaderboard, 82.76 to 62.83.
Which is better for agentic tasks, Claude Fable 5 or GPT-5.5 Pro?
GPT-5.5 Pro has the edge for agentic tasks in this comparison, averaging 90.1 versus 84.6. Claude Fable 5 stays close enough that the answer can still flip depending on your workload.