Claude Sonnet 5.5
Claude Sonnet 5.5
Nearly the strongest model in the index, at a mid-range price. Sonnet stopped being the compromise.
Updated
The read
Sonnet 5.5 is the surprise of the autumn releases. It costs the same as Sonnet 5 and scores second only to Opus 5.5 on the Artificial Analysis index, ahead of every OpenAI and Google model. Human voters rate it lower than its benchmarks suggest, which is why it sits below Opus on craft here. For coding agents, editor integrations and anything that runs all day, it is the best value at the top of the field.
Where it shines
- Second-highest Artificial Analysis score in the index, at a fifth of the Fable price
- Top-tier terminal and computer-use results
- Cheaper cached input since October, which helps long agent loops
Worth knowing first
- Rated lower by human voters than by benchmarks, so test it on your own prompts
- Still trails Opus 5.5 on the hardest reasoning
Index score
91.5
Provisional. This score is read from the product's public capability, not from the one-prompt rebuild the fully reviewed entries went through, so treat it as a placing rather than a verdict.
- Rank
- 02 of 73
- Builds
- LLMs
- Category
- Coding
- Output
- Text, code and tool calls over an API
- Pricing
- Paid only
- Best for
- Coding agents and editor integrations that run all day
Scores are our own editorial judgement, weighted craft 55, speed 10, control 15 and value 20.
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- 37Step 3.7 FlashStep 3.7 FlashProvisionalAn Apache-licensed vision model built for coding agents, and it routes work rather than brute-forcing it.Coding modelFree tier81.6
