Top picks for Code Documentation (2026)
Writing clear docstrings and READMEs that match the code. Ranked from 464 live models on the OpenRouter catalog, weighted for context window, low cost, reasoning quality.
Updated 2026-10-19 · prices checked at this morning's rebuild
Which should you use? DeepSeek: DeepSeek V4 Pro 0423 tops this ranking on blended score. If cost drives the decision, Google: Gemini 2.5 Flash (batch) is the cheapest of the leaders at $0.15/M input.
| # | Model | Score | In / 1M | Out / 1M | Context | |
|---|---|---|---|---|---|---|
| 1 | DeepSeek: DeepSeek V4 Pro 0423deepseek/deepseek-v4-pro | 141 | $0.96 | $1.91 | 1,048,576 | Details → |
| 2 | Google: Gemini 3.1 Pro Preview (batch)google/gemini-3.1-pro-preview:batch | 141 | $1.00 | $6.00 | 1,048,576 | Details → |
| 3 | Anthropic: Claude Sonnet 4.6 (batch)anthropic/claude-sonnet-4.6:batch | 140 | $1.50 | $7.50 | 1,000,000 | Details → |
| 4 | Anthropic: Claude Opus 4.7 (batch)anthropic/claude-opus-4.7:batch | 139 | $2.50 | $12.50 | 1,000,000 | Details → |
| 5 | Google: Gemini 3.1 Pro Previewgoogle/gemini-3.1-pro-preview | 139 | $2.00 | $12.00 | 1,048,576 | Details → |
| 6 | Google: Gemini 2.5 Flash (batch)google/gemini-2.5-flash:batch | 139 | $0.15 | $1.25 | 1,048,576 | Details → |
| 7 | Anthropic: Claude Sonnet 5.5 (batch)anthropic/claude-sonnet-5.5:batch | 139 | $1.00 | $5.00 | 1,000,000 | Details → |
| 8 | Google: Gemini 2.5 Flashgoogle/gemini-2.5-flash | 139 | $0.30 | $2.50 | 1,048,576 | Details → |
| 9 | Google: Gemini 4 Argon (batch)google/gemini-4-argon:batch | 138 | $1.00 | $5.00 | 1,048,576 | Details → |
| 10 | Xiaomi: MiMo-V2.6-Proxiaomi/mimo-v2.6-pro | 138 | $0.43 | $0.87 | 1,050,000 | Details → |
| 11 | OpenAI: GPT-6.1 Sol (batch)openai/gpt-6.1-sol:batch | 138 | $1.00 | $5.00 | 1,050,000 | Details → |
| 12 | Anthropic: Claude Sonnet 4.6anthropic/claude-sonnet-4.6 | 138 | $3.00 | $15.00 | 1,000,000 | Details → |
| 13 | Anthropic: Claude Haiku 5.5 (batch)anthropic/claude-haiku-5.5:batch | 138 | $0.05 | $0.25 | 1,000,000 | Details → |
| 14 | Anthropic: Claude Haiku 5.5anthropic/claude-haiku-5.5 | 138 | $0.10 | $0.50 | 1,000,000 | Details → |
| 15 | Anthropic: Claude Opus 5.5 (batch)anthropic/claude-opus-5.5:batch | 138 | $2.00 | $10.00 | 1,000,000 | Details → |
How we ranked these
For Code Documentation, we weight models on context window, low cost, reasoning quality. Scores combine each model's public specs with independent benchmark results (Aider Polyglot coding scores, Artificial Analysis intelligence/coding/agentic indices) and live pricing. See full methodology →
About Code Documentation
yourself.
When to use: Use this when you have working code without documentation, or when you need to update docs to match a recent code change without manually writing every
Common questions
What is the difference between AI documentation and human-written docs?
AI-generated documentation excels at speed and consistency for straightforward functions, but often misses domain context, usage warnings, and examples that experienced developers would include. Models like Claude 3.5 Sonnet handle complex parameter relationships better than older models, but you should always review critical paths and add use-case examples manually.
How much slower is it to use a better model for documentation versus a faster one?
GPT-4 or Claude 3.5 Sonnet are typically 2-4x slower per file than GPT-3.5, but produce fewer errors that require rewrites. For a 500-file codebase, the slower model still finishes in hours rather than minutes, and the time savings from not fixing bad docs usually outweigh the generation delay.