Claude vs ChatGPT vs Gemini vs Grok: which AI should read your long documents?
Anthropic, OpenAI, Google and SpaceXSI have all shipped new flagship models recently. We lined them up for one job every business has: reading long documents (contracts, catalogs, supplier PDFs, reports) and answering questions you'll act on.
This is a spec sheet from each company's own docs, checked Oct 19, 2026. It is not our own test. Prices change; re-check before you build on them.
The spec sheet
| Claude Opus 5.5 | ChatGPT GPT-6.1 Sol | Gemini 4 Argon | Grok 4.7 | |
|---|---|---|---|---|
| Made by | Anthropic | OpenAI | SpaceXSI | |
| Where to get it | Claude app (Pro, Max, Team, Enterprise) and API | ChatGPT Work and Codex (Plus and up), and API | Gemini app (Google AI Pro and Ultra) and API | xAI API, Grok Build and Cursor |
| Reads at once (context window) | 1M tokens | 1.05M tokens | 1M tokens, shared with the answer | 500K tokens |
| Takes in (API) | Text, images | Text, images | Multimodal (see Google's docs) | Text, images |
| API price per 1M tokens, in / out | $4 / $20 | $2 / $10 (2x input above 272K) | $2 / $10 intro price to Nov 30, then $4 / $20 | $2 / $6 |
| In the maker's words | Built for long-running agentic coding and knowledge work | "Near-Astra performance at a lower cost" (Astra is OpenAI's pricier model) | Built for deep work on complex tasks; #1 on the Vals Index, per Google | Built-in web search and X search tools in the API |
| Pick it for | Long, multi-step analysis | The same document job, many times | Document-heavy work (re-check the price after Nov 30) | Long docs plus what X is saying |
Our read
There's no single winner on paper. If you run the same document job many times, GPT-6.1 Sol and Gemini 4 Argon list at the same API price until Nov 30, when Argon's price doubles. Grok 4.7 is the cheapest per output token here and reads half as much at once. Claude Opus 5.5 has the highest list price of the four today. The only test that matters is your own document.
Run this 10-minute test on your own document
Upload the same long document to each AI you're considering and send the same prompt. Then check every answer against the page it cites.
Read the attached document. Answer these 5 questions, and after each answer quote the exact sentence and page it comes from:
1. [A date or deadline in the document]
2. [A price, fee or penalty]
3. [Who is responsible for X]
4. [Something the document does NOT say, to see if it admits that]
5. [A question that needs two sections combined]
If the document doesn't answer a question, say "not in the document". Don't guess.- Score each AI: correct answer, correct quote, and honest "not in the document" on question 4.
- Use a document you're allowed to share. Remove personal data you don't need.
- Check your plan's data settings before uploading anything confidential.
Sources (checked Oct 19, 2026)
- https://www.anthropic.com/claude-opus-5-5
- https://platform.claude.com/docs/en/models/opus-5-5/overview
- https://openai.com/index/introducing-gpt-6-1-sol/
- https://developers.openai.com/api/docs/models/gpt-6.1-sol
- https://blog.google/innovation-and-ai/models-and-research/gemini-models/introducing-gemini-4-argon/
- https://docs.x.ai/developers/grok-4-7
Everything here writes drafts: you review and send. No income or ranking promises. Not affiliated with or endorsed by Anthropic, OpenAI, xAI or Google.