Best LLMs for Instruction Following — Anthropic
The best Anthropic model for instruction following is Claude Fable 5, satisfying 63.5% of IFBench's verifiable prompt constraints. Claude Opus 4.8 (62.2%) and Claude Opus 4.7 (58.6%) round out the top three.
- 1
claude-fable-5ReasoningToolsJSON+159.9 intel · $10.00/M · 82 t/s63.5%IFBench - 2claude-opus-4.8ReasoningToolsJSON+155.7 intel · $5.00/M · 1M ctx62.2%IFBench
- 3claude-opus-4.7ReasoningToolsJSON+153.5 intel · $5.00/M · 1M ctx58.6%IFBench
- 4claude-sonnet-4ReasoningToolsVision25.5 intel · $3.00/M · 46 t/s45.4%IFBench
- 5claude-opus-4.6ReasoningToolsJSON+137.8 intel · $5.00/M · 1M ctx44.6%IFBench
- 6claude-opus-4ReasoningToolsVision25.5 intel · $15.00/M · 23 t/s43.3%IFBench
- 7claude-opus-4.5ReasoningToolsJSON+134.7 intel · $5.00/M · 52 t/s43.0%IFBench
- 8claude-sonnet-4.5ReasoningToolsJSON+129.3 intel · $3.00/M · 36 t/s42.7%IFBench
- 9claude-haiku-4.5ReasoningToolsJSON+123.7 intel · $1.00/M · 91 t/s42.0%IFBench
- 10claude-sonnet-4.6ReasoningToolsJSON+135.9 intel · $3.00/M · 1M ctx41.2%IFBench
- 11claude-3-haikuToolsVision3.9 intel · $0.250/M · 200K ctx36.1%IFBench
How this is ranked
AI models ranked by IFBench — how reliably a model obeys explicit, verifiable constraints in the prompt (format, length, inclusion and exclusion rules). High scores mean fewer retries and less prompt-wrangling in production, which often matters more than raw intelligence for pipelines.
Frequently asked
Which Anthropic model follows instructions most reliably?
The best Anthropic model for instruction following is Claude Fable 5, satisfying 63.5% of IFBench's verifiable prompt constraints. Claude Opus 4.8 (62.2%) and Claude Opus 4.7 (58.6%) round out the top three.
What's a good alternative to Claude Fable 5?
Claude Opus 4.8 (62.2%) is the closest alternative on this metric, followed by Claude Opus 4.7 (58.6%). See the full ranking above for the tradeoffs.
How many Anthropic models are there?
modelgrep tracks 17 Anthropic models with live benchmarks, speed, latency and per-provider pricing, led on intelligence by Claude Opus 5. 11 of them qualify for this ranking.