Claude Sonnet 5.5 is the best AI for documentation. Good docs need technical accuracy and readable prose at the same time, and Sonnet 5.5 is strong at both: it can read the code it is documenting, explain it in plain language, and keep a consistent structure across many pages. For API references generated from code at volume, Claude Haiku 5.5 is a cheap first draft; for deeply technical architecture docs, GPT-6.1 Sol is an equally good choice.
The safest documentation default, the cheaper option worth trying first, and the specialist pick — before you read the detail below.
Claude Sonnet 5.5 is the strongest answer here for documentation — pick it when quality of output matters more than the $2.00/1M/1M input you pay for it.
Claude Haiku 5.5 handles the same job for about 95% less per token. Start here and only move up if the output is not good enough.
GPT-6.1 Sol is the fastest of these for documentation — worth it when latency is what the reader notices, not the last few points of reasoning depth.
Claude Sonnet 5.5 is the best documentation model for clarity with technical accuracy.
GPT-6.1 Sol is equally strong for systems and architecture documentation.
Claude Haiku 5.5 is the cheap option for generating reference docs at volume.
Use Claude Sonnet 5.5 for guides, onboarding docs and READMEs that people actually read.
Use GPT-6.1 Sol for API design docs, architecture notes and technical handoffs.
Use Claude Haiku 5.5 when documentation volume is high and a person will edit the drafts.
Switch the scoring lens to see whether the documentation answer changes when cost, speed, or long-document depth leads the decision.
Anthropic / Balanced / Oct 10, 2026
Near-Opus 5.5 quality on scoped work at half the price.
Ranks models by the broadest mix of coding, writing, research, and long-context usefulness.
The work is long, ambiguous and multi-step — Anthropic positions Opus 5.5 for exactly that — or you need the lowest possible price, where Haiku 5.5 costs a twentieth as much.
Where the documentation recommendation shifts once you weigh price or latency differently.
Near-Opus 5.5 quality on scoped work at half the price.
Near-Astra capability at Sol pricing — OpenAI's value pick.
Anthropic's budget model, now with adjustable reasoning, at $0.10/$0.50.
List prices and published scores — the numbers this page's pick is built from.
| Model | Input | Output | Est. month | Context | Speed | Coding | Writing | Research |
|---|---|---|---|---|---|---|---|---|
| Claude Sonnet 5.5Anthropic | $2.00/1M | $10.00/1M | $40 | 1M tokens | Fast | 98 | 98 | 95 |
| GPT-6.1 SolOpenAI | $2.00/1M | $10.00/1M | $40 | 1.1M tokens | Balanced | 98 | 94 | 97 |
| Claude Haiku 5.5Anthropic | $0.10/1M | $0.50/1M | $2.00 | 1M tokens | Very fast | 86 | 84 | 82 |
Scores out of 100 — how we evaluate models. “Est. month” is 10M in / 2M out at list price: a ceiling, no discounts.
Why each one is on the shortlist for documentation, what it is genuinely good at, and where we would steer you away from it.
Ranked first here for documentation: 98/100 on coding, with the widest margin of anything in this line-up.
Anthropic's September 28, 2026 Sonnet — built for well-scoped everyday work like features, bug fixes, documents, slides and spreadsheets, priced at $2/$10 and close to Opus 5.5 on most of Anthropic's launch rows.
The work is long, ambiguous and multi-step — Anthropic positions Opus 5.5 for exactly that — or you need the lowest possible price, where Haiku 5.5 costs a twentieth as much.
The model most people should default to in the Claude lineup. Sonnet 5.5 lands within a few points of Opus 5.5 on most of Anthropic's launch rows, beats it on Terminal-Bench 4.0, and costs half as much. Step up to Opus 5.5 only when the task is open-ended and long.
Full pricing, benchmark table and release notes on the Claude Sonnet 5.5 page.
Here for latency: it answers fastest of anything listed for documentation, at 98/100 on coding.
OpenAI's September 29, 2026 DevDay release — a Sol-tier reasoning model that OpenAI says comes close to GPT-6 Astra on agentic coding, computer use and professional work at one fifth of Astra's price.
You need it inside ordinary ChatGPT chats today, or your prompts regularly pass 272K tokens where the rate doubles.
OpenAI's best value for serious work. GPT-6.1 Sol replaces both GPT-6 Sol and, for most teams, GPT-6 Astra: independent testing has it a point behind Astra at a fifth of the list price. Pick Astra only when the last point of capability is worth five times the bill.
Full pricing, benchmark table and release notes on the GPT-6.1 Sol page.
Where most budgets should land for documentation — about 95% less per token than Claude Sonnet 5.5, and still 86/100 on the coding axis.
Anthropic's budget model, now with adjustable reasoning, at $0.10/$0.50. Full Claude Haiku 5.5 review →
UseRightAI recommendations are based on practical decision factors people actually feel in day-to-day use.
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For documentation, Claude Sonnet 5.5 (Anthropic) is our pick. Near-Opus 5.5 quality on scoped work at half the price. It costs $2/1M input and $10/1M output tokens, with a 1M-token context window — enough headroom for all but the largest documentation jobs. GPT-6.1 Sol is the closest alternative if it doesn't fit your setup.
Because the work it is built for overlaps closely with documentation: day-to-day feature and bug-fix work in an IDE or coding agent, where speed matters more than ceiling and drafting documents, slide decks and spreadsheets that need to be presentable on the first pass. The model most people should default to in the Claude lineup. Sonnet 5.5 lands within a few points of Opus 5.5 on most of Anthropic's launch rows, beats it on Terminal-Bench 4.0, and costs half as much. Step up to Opus 5.5 only when the task is open-ended and long.
On a moderate month — 10M input and 2M output tokens — Claude Sonnet 5.5 runs about $40.00 at list price, with no batch or caching discounts applied, so treat that as a ceiling. Claude Haiku 5.5 is the cheaper route at roughly $2.00 for the same volume, if documentation is high-volume enough for price to lead the decision.
Anthropic itself says Opus 5.5 is better on loosely defined tasks that need longer reasoning. Trails Opus 5.5 on Humanity's Last Exam (64.5% vs 67.7%). Avoid it if the work is long, ambiguous and multi-step — Anthropic positions Opus 5.5 for exactly that — or you need the lowest possible price, where Haiku 5.5 costs a twentieth as much. None of that rules it out for documentation on its own — but if one of those limits maps onto how you actually work, take the alternative on this page seriously rather than defaulting to the top pick.
Claude Haiku 5.5 at $0.1/1M input is the budget option here. Anthropic's budget model, now with adjustable reasoning, at $0.10/$0.50. Expect a quality step down on the hardest cases — the usual pattern is to route routine documentation volume to Claude Haiku 5.5 and keep Claude Sonnet 5.5 for the work where a wrong answer is expensive.
Claude Haiku 5.5, rated very fast against Claude Sonnet 5.5's fast. Speed matters most for interactive and high-volume work; if your documentation runs in the background, the slower and more capable model is usually the better trade.