Model comparison
Claude Fable 5 vs Claude Opus 4.8
Head-to-head evidence from 32 shared benchmark results across 6 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: Claude Fable 5 #3 (Supported); Claude Opus 4.8 #6 (Supported). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Claude Fable 5 and Claude Opus 4.8 share 32 comparable benchmark results. 3 of 8 categories are comparable. 2 results are unique to Claude Fable 5; 23 to Claude Opus 4.8.
Updated July 24, 2026- Shared results
- 32
- Claude Fable 5 only
- 2
- Claude Opus 4.8 only
- 23
- Comparable categories
- 3 / 8
Pick Claude Fable 5 if you want the stronger benchmark profile. Claude Opus 4.8 only becomes the better choice if multimodal & grounded is the priority or you want the cheaper token bill.
Confidence note. This is a partial-evidence comparison with 32 shared benchmark results across 6 evidence categories; 3 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 77.44. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
Claude Fable 5's sharpest advantage is in coding, where it averages 89.2 against 81.1. The single biggest benchmark swing on the page is SWE-bench Pro, 80% to 69.2%. Claude Opus 4.8 does hit back in multimodal & grounded, so the answer changes if that is the part of the workload you care about most.
Claude Fable 5 is also the more expensive model on tokens at $10.00 input / $50.00 output per 1M tokens, versus $5.00 input / $25.00 output per 1M tokens for Claude Opus 4.8. That is roughly 2.0x on output cost alone. Claude Fable 5 gives you the larger context window at 1M+, compared with 1M for Claude Opus 4.8.
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 | Claude Opus 4.8 |
|---|---|---|---|
| Multimodal | Claude Fable 557.9 | Margin→ 19.1 | Claude Opus 4.877.0 |
| Coding | Claude Fable 589.2 | Margin← 8.1 | Claude Opus 4.881.1 |
| Agentic | Claude Fable 584.6 | Margin← 4.3 | Claude Opus 4.880.3 |
| Reasoning | Claude Fable 5Not measured | MarginNo overlap | Claude Opus 4.872.1 |
| Knowledge | Claude Fable 5Not measured | MarginNo overlap | Claude Opus 4.862.7 |
| Math | Claude Fable 5Not measured | MarginNo overlap | Claude Opus 4.853.9 |
Decisive benchmark drivers
The largest measured benchmark gaps in this matchup, with exact reported values.
More
- Source ↗
SWE-bench Pro
CodingA 80%B 69.2%Winner: Claude Fable 5Δ 10.8SWE-bench Pro: Claude Fable 5 scored 80%; Claude Opus 4.8 scored 69.2%. Claude Fable 5 wins this benchmark. - Source ↗
Terminal-Bench 2.0
AgenticA 84.3%B 74.6%Winner: Claude Fable 5Δ 9.7Terminal-Bench 2.0: Claude Fable 5 scored 84.3%; Claude Opus 4.8 scored 74.6%. Claude Fable 5 wins this benchmark. - Source ↗
OfficeQA Pro
MultimodalA 57.9%B 66.2%Winner: Claude Opus 4.8Δ 8.3OfficeQA Pro: Claude Fable 5 scored 57.9%; Claude Opus 4.8 scored 66.2%. Claude Opus 4.8 wins this benchmark. - Source ↗
SWE-bench Verified
CodingA 95%B 88.6%Winner: Claude Fable 5Δ 6.4SWE-bench Verified: Claude Fable 5 scored 95%; Claude Opus 4.8 scored 88.6%. Claude Fable 5 wins this benchmark. - Source ↗
OSWorld-Verified
AgenticA 85%B 83.4%Winner: Claude Fable 5Δ 1.6OSWorld-Verified: Claude Fable 5 scored 85%; Claude Opus 4.8 scored 83.4%. Claude Fable 5 wins this benchmark.
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | Claude Fable 5 | Claude Opus 4.8 | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Claude Fable 5$10 input / $50 output | Claude Opus 4.8$5 input / $25 output | Claude Opus 4.8 has the lower combined listed price. |
| Generation speedtokens per second | Claude Fable 5Not available | Claude Opus 4.8Not available | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | Claude Fable 5Not available | Claude Opus 4.8Not available | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | Claude Fable 51M+ | Claude Opus 4.81M | Claude Fable 5 lists the larger context window. |
Benchmark Deep Dive
AgenticClaude Fable 5 wins21 benchmarks
| Benchmark | Claude Fable 5 | Claude Opus 4.8 | Result |
|---|---|---|---|
| Terminal-Bench 2.0Source | 84.3% | 74.6% | Claude Fable 5 leads |
| OSWorld-VerifiedSource | 85% | 83.4% | Claude Fable 5 leads |
| GDPval-AASource | 1747 | 1593 | Claude Fable 5 leads |
| AA Agentic IndexSource | 52.8% | 47.2% | Claude Fable 5 leads |
| τ²-bench resultsSource | 98.5% | 94.4% | Claude Fable 5 leads |
| GDPval-AASource | 62.3% | 54.6% | Claude Fable 5 leads |
| AA BriefcaseSource | 1574 | 1346 | Claude Fable 5 leads |
| AA AutomationBenchSource | 48.6% | 48.5% | Claude Fable 5 leads |
| AA EnterpriseOps-GymSource | 51.1% | 44.0% | Claude Fable 5 leads |
| AA Harvey LABSource | 93.6% | 91.1% | Claude Fable 5 leads |
| AA Tau3 BankingSource | 26.8% | 27.6% | Claude Opus 4.8 leads |
| terminalBenchHardSource | 62.9% | 58.3% | Claude Fable 5 leads |
| aaTerminalBench21Source | 84.6% | 84.6% | Tie |
| BrowseCompSource | — | 84.3% | Not comparable |
| DeepSearchQASource | — | 93.1% | Not comparable |
| Finance Agent v2Source | — | 53.9% | Not comparable |
| MCP AtlasSource | — | 82.2% | Not comparable |
| ToolathlonSource | — | 59.9% | Not comparable |
| Gert LabsSource | — | 72.97% | Not comparable |
| ResearchClawBenchSource | — | 21.1% | Not comparable |
| OSWorld 2.0Source | — | 20.6% | Not comparable |
CodingClaude Fable 5 wins11 benchmarks
| Benchmark | Claude Fable 5 | Claude Opus 4.8 | Result |
|---|---|---|---|
| SWE-bench VerifiedSource | 95% | 88.6% | Claude Fable 5 leads |
| SWE-bench ProSource | 80% | 69.2% | Claude Fable 5 leads |
| FrontierCode 1.1 MainSource | 53.5% | 46.5% | Claude Fable 5 leads |
| Terminal-Bench 2.0Source | 84.3% | 74.6% | Claude Fable 5 leads |
| cursorBench31Source | 70.6% | 58.4% | Claude Fable 5 leads |
| cursorBench32Source | 70.5% | 62.3% | Claude Fable 5 leads |
| VulcanBench v3Source | 87.0% | — | Not comparable |
| AA Coding IndexSource | 76.5% | 74.3% | Claude Fable 5 leads |
| AA-SciCodeSource | 60.2% | 53.5% | Claude Fable 5 leads |
| SWE MultilingualSource | — | 84.4% | Not comparable |
| SWE MultimodalSource | — | 38.4% | Not comparable |
Reasoning4 benchmarks
Knowledge10 benchmarks
| Benchmark | Claude Fable 5 | Claude Opus 4.8 | Result |
|---|---|---|---|
| Artificial Analysis Intelligence IndexSource | 59.9% | 55.7% | Claude Fable 5 leads |
| AA-GPQA DiamondSource | 92.6% | 92.0% | Claude Fable 5 leads |
| AA-HLESource | 53.3% | 45.7% | Claude Fable 5 leads |
| AA-Omniscience IndexSource | 40.2% | 27.4% | Claude Fable 5 leads |
| AA-Omniscience AccuracySource | 61.4% | 46.6% | Claude Fable 5 leads |
| AA-Omniscience Hallucination RateSource | 54.9% | 35.9% | Claude Opus 4.8 leads |
| GPQASource | — | 93.6% | Not comparable |
| GPQA-DSource | — | 93.6% | Not comparable |
| HLESource | — | 57.9% | Not comparable |
| HLE w/o toolsSource | — | 49.8% | Not comparable |
Math3 benchmarks
Multilingual1 benchmarks
| Benchmark | Claude Fable 5 | Claude Opus 4.8 | Result |
|---|---|---|---|
| INCLUDESource | — | 87.6% | Not comparable |
MultimodalClaude Opus 4.8 wins6 benchmarks
| Benchmark | Claude Fable 5 | Claude Opus 4.8 | Result |
|---|---|---|---|
| Blueprint-Bench 2Source | 38.6% | — | Not comparable |
| OfficeQA ProSource | 57.9% | 66.2% | Claude Opus 4.8 leads |
| Design Arena WebsiteSource | 1332 | 1270 | Claude Fable 5 leads |
| ScreenSpot ProSource | — | 87.9% | Not comparable |
| CharXivSource | — | 89.9% | Not comparable |
| CharXiv w/o toolsSource | — | 80.5% | Not comparable |
Inst. Following1 benchmarks
| Benchmark | Claude Fable 5 | Claude Opus 4.8 | Result |
|---|---|---|---|
| AA-IFBenchSource | 63.5% | 62.2% | Claude Fable 5 leads |
Frequently Asked Questions (4)
Which is better, Claude Fable 5 or Claude Opus 4.8?
Claude Fable 5 is ahead on BenchLM's BenchAlign leaderboard, 82.76 to 77.44. The biggest single separator in this matchup is SWE-bench Pro, where the scores are 80% and 69.2%.
Which is better for coding, Claude Fable 5 or Claude Opus 4.8?
Claude Fable 5 has the edge for coding in this comparison, averaging 89.2 versus 81.1. Inside this category, cursorBench31 is the benchmark that creates the most daylight between them.
Which is better for agentic tasks, Claude Fable 5 or Claude Opus 4.8?
Claude Fable 5 has the edge for agentic tasks in this comparison, averaging 84.6 versus 80.3. Inside this category, AA Briefcase is the benchmark that creates the most daylight between them.
Which is better for multimodal and grounded tasks, Claude Fable 5 or Claude Opus 4.8?
Claude Opus 4.8 has the edge for multimodal and grounded tasks in this comparison, averaging 77 versus 57.9. Inside this category, Design Arena Website is the benchmark that creates the most daylight between them.