Compare / head-to-head
Claude Fable 5vs
Seed1.8
Claude Fable 5 leads 2 of 2 shared benchmarks. Seed1.8 is 26.7x cheaper per token. Claude Fable 5 has the larger context window (1M tokens).
Benchmarks from cited public sources; pricing from official pages; status from official provider feeds.
Shared benchmarks
2 – 0
Claude Fable 5 leads
Cheaper per token
Seed1.8
26.7x cheaper, input + output
Larger context
Claude Fable 5
1M tokens
Providers
2 providers
Anthropic · ByteDance Seed
Claude Fable 5
Anthropic · released 2026-06-09
textvision
Quality
Benchmark matrix
2 shared · 42 only Claude Fable 5 · 14 only Seed1.8| Benchmark | Claude Fable 5 | Seed1.8 | Δ | Edge |
|---|---|---|---|---|
| Reported by both · 2 | ||||
| SWE-bench Verified | 95% ↗ | 72.9% ↗ | +22.1 pt | Claude Fable 5 |
| OSWorld-Verified (XLANG) | 86% ↗ | 61.9% ↗ | +24.1 pt | Claude Fable 5 |
| Only Claude Fable 5 reports · 42 | ||||
| GPQA Diamond | 85.9% ↗epoch run | not reported | — | — |
| LMArena Elo | 1504.3 ↗ | not reported | — | — |
| APEX-Agents (Mercor) | 63.6% ↗ | not reported | — | — |
| AutomationBench | 17.4% ↗ | not reported | — | — |
| Blueprint-Bench 2 | 38.6% ↗ | not reported | — | — |
| Chess Puzzles (Epoch AI run) | 41% ↗epoch run | not reported | — | — |
| CursorBench | 72.9% ↗ | not reported | — | — |
| DeepSWE v1.1 (Datacurve) | 69.9% ↗ | not reported | — | — |
| EBR-bench (Epoch AI run) | 39.5% ↗epoch run | not reported | — | — |
| FrontierCode (Diamond) | 29.3% ↗ | not reported | — | — |
| FrontierMath Tier 4 v2 (Epoch AI run) | 90.2% ↗epoch run | not reported | — | — |
| FrontierMath Tiers 1-3 v2 (Epoch AI run) | 87% ↗epoch run | not reported | — | — |
| FrontierSWE V2 (Proximal Labs) | 47% ↗ | not reported | — | — |
| Furniture Assembly (Epoch AI run) | 35.8% ↗epoch run | not reported | — | — |
| GDP.pdf | 29.8% ↗ | not reported | — | — |
| GSO Opt@1 (GSO) | 76.5% ↗ | not reported | — | — |
| Legal Agent Benchmark (Harvey's Held-Out Set) | 13.3% ↗ | not reported | — | — |
| LiveBench Agentic Coding (LiveBench) | 62.2% ↗ | not reported | — | — |
| LiveBench Coding (LiveBench) | 86% ↗ | not reported | — | — |
| LiveBench Data Analysis (LiveBench) | 80.5% ↗ | not reported | — | — |
| LiveBench Instruction Following (LiveBench) | 75.8% ↗ | not reported | — | — |
| LiveBench Language (LiveBench) | 90.7% ↗ | not reported | — | — |
| LiveBench Mathematics (LiveBench) | 96% ↗ | not reported | — | — |
| LiveBench Reasoning (LiveBench) | 89.7% ↗ | not reported | — | — |
| LMArena Agent (LMArena) | 0.0821 ↗ | not reported | — | — |
| LMArena Vision (LMArena) | 1308.8 ↗ | not reported | — | — |
| LMArena WebDev (LMArena) | 1625.3 ↗ | not reported | — | — |
| MirrorCode (Epoch AI run) | 63.9% ↗epoch run | not reported | — | — |
| Mystery Game Puzzles (Epoch AI run) | 52% ↗epoch run | not reported | — | — |
| OfficeQA Pro | 57.9% ↗ | not reported | — | — |
| OSWorld-Verified | 85% ↗ | not reported | — | — |
| OTIS Mock AIME 2024-2025 (Epoch AI run) | 100% ↗epoch run | not reported | — | — |
| SAGE (Vals AI) | 51.9% ↗ | not reported | — | — |
| SimpleBench (SimpleBench) | 81.9% ↗ | not reported | — | — |
| SimpleQA Verified | 70.7% ↗epoch run | not reported | — | — |
| SWE-Bench Pro | 80% ↗ | not reported | — | — |
| SWE-rebench 2026-05-15 to 2026-07-01 (Nebius) | 64.5% ↗ | not reported | — | — |
| tau2-bench Banking Knowledge (Sierra) | 39.7% ↗ | not reported | — | — |
| Terminal-Bench 2.1 | 84.3% ↗ | not reported | — | — |
| Terminal-Bench 4.0 (Vals AI) | 41.4% ↗ | not reported | — | — |
| Vending-Bench 2 (Andon Labs) | 5680.26 ↗ | not reported | — | — |
| WeirdML (Håvard Tveit Ihle) | 91.9% ↗ | not reported | — | — |
| Only Seed1.8 reports · 14 | ||||
| MMLU-Pro | not reported | 84.9% ↗ | — | — |
| AIME-25 | not reported | 94.3% ↗ | — | — |
| ARC-AGI-1 | not reported | 67.9% ↗ | — | — |
| BFCL-v4 | not reported | 57.2% ↗ | — | — |
| BrowseComp-en | not reported | 67.6% ↗ | — | — |
| GPQA-Diamond | not reported | 83.8% ↗ | — | — |
| HLE (text-only, agentic search) | not reported | 40.9% ↗ | — | — |
| LiveCodeBench(v6) | not reported | 79.5% ↗ | — | — |
| MM-BrowseComp | not reported | 46.3% ↗ | — | — |
| Multi-SWE-Bench | not reported | 42% ↗ | — | — |
| MultiChallenge | not reported | 66.7% ↗ | — | — |
| Terminal Bench 2.0 | not reported | 45.2% ↗ | — | — |
| WideSearch | not reported | 63.8% ↗ | — | — |
| τ2-Bench | not reported | 72% ↗ | — | — |
Scores tagged "epoch" or "matharena" are independent runs, used only where the lab has not published its own; ⚠ marks rows MathArena flags as released after the competition. Higher is better on every row. Δ is Claude Fable 5 minus Seed1.8 in the benchmark's own unit. "Not reported" means the lab has not published that figure; it is not a zero. ↗ opens the source.
Specs & pricing
Side by side
Official pricing pages and model cards| Spec | Claude Fable 5 | Seed1.8 | Edge |
|---|---|---|---|
| Context window | 1M tokens | 256K tokens | Claude Fable 5 |
| Max output | 128K tokens | 64K tokens | Claude Fable 5 |
| Input price / 1M | $10 ↗ | $0.25 ↗ | Seed1.8 |
| Output price / 1M | $50 ↗ | $2 ↗ | Seed1.8 |
| Cached input / 1M | $1 ↗ | $0.05 ↗ | Seed1.8 |
| Input + output / 1M Lower is cheaper. List prices; batch, tool and regional fees excluded. | $60 | $2.25 | Seed1.8 |
| Modalities | text · vision | text · vision · video | Seed1.8 |
| Released | 2026-06-09 | 2025-12-18 | — |
| Cited benchmark scores | 44 | 16 | — |
Reliability
Provider status
Live from /statusMore matchups
Claude Fable 5 vs …
Models sharing the most benchmarksMore matchups
Seed1.8 vs …
Models sharing the most benchmarksBuilt by Respan
Which one wins on your data?
Public benchmarks are a starting point. Run Claude Fable 5 and Seed1.8 on your own prompts with Respan evals, or route to either through one gateway key with automatic failover.