Claude Fable 5.

specs at a glance

how good is Claude Fable 5 at coding?

Claude Fable 5 sits at #6 of 28 ranked models, posting 95.0% on SWE-bench Verified — 2 points behind #1 Claude Opus 5. On the harder SWE-bench Pro it scores 80.3%.

Score provenance: Independent (vals.ai, Jul 14 2026, mini-swe-agent bash-only harness): SWE-bench Verified 95.00% ±0.98. Held the top score until GPT-5.6 Sol was evaluated at 96.20% ±0.86, and now sits third behind Claude Opus 5 (97.00% ±0.76, added Jul 25 2026). All three are within the combined margin of error of each other. Against Sol it is a 1.2-point gap — a 1.2-point gap that is inside the combined margin of error (~0.9 sigma), so the two are a statistical tie and we rank Sol first only because it scored higher. Re-confirmed 2026-08-16: vals.ai still measures 95.00% ±0.98, unchanged across three sweeps (Aug 13, 15, 16), and Grok 4.6 sits above it at 95.60% ±0.92, a 0.6-point gap that is inside the combined margin of error and should be read as a tie. SWE-bench Pro 80.3% uses Anthropic's own scaffolding and is contested. Restored Jul 1, 2026 after a 20-day export-control suspension. Pricing $10/$50 per 1M.

what does Claude Fable 5 cost?

$10 per 1M input tokens and $50 per 1M output — #26 cheapest of the 26 models we track. Coding workloads are output-heavy, so weight the output rate when budgeting. Run your own volume through the AI API cost calculator for a monthly estimate.

where can you use it?

Available via API · Claude Code · Claude Cowork · claude.ai. As a proprietary model, you're on the maker's infrastructure and release schedule.

Full storyClaude Fable 5 Broke a Math Conjecture Open Since 1939

Ranked on our AI Coding Leaderboard — scores confirmed against primary sources only, updated 2026-08-20.