Checked October 1, 2026. This comparison separates documented model limits, release access, and evaluation evidence. OpenAI’s API model name is GPT-6.1 Sol; ChatGPT is a product that can expose models and tools, rather than the API model’s name.
What the official specifications confirm
| Model | Access described by its vendor | Context window | Maximum output |
|---|---|---|---|
| Claude Sonnet 5.5 | Active Claude API model; released September 28 | 1 million tokens | 128,000 tokens for standard requests |
| GPT-6.1 Sol | Documented OpenAI API model | 1,050,000 tokens | 128,000 tokens |
| Gemini 4 Argon | Limited Fairwind rollout; wider release planned | Not established by the announcement reviewed here | 1 million tokens, as announced |
Sources: Anthropic’s Sonnet 5.5 specifications, OpenAI’s GPT-6.1 Sol model reference, and Google’s September 30 Argon announcement.
Context and output are different limits
A context window governs the material a model can work with during a request. An output limit governs how much it can generate. Neither number measures factual accuracy or guarantees that every detail in a long document will be retrieved correctly.
Google’s Argon announcement describes increasing the output limit to one million tokens. That figure should not be presented as a two-million-token input context window. Similarly, a model’s total context capacity does not mean an application can fill it with input while still reserving unlimited room for generated text.
How to compare coding and reasoning fairly
A useful comparison needs the same tasks, tools, scoring rules, and effort settings. Vendor results from different evaluations cannot be combined into a single ranking as if the conditions matched. Anthropic’s launch report presents several evaluations with their own settings and qualifications; those are vendor-reported results, not GadgetsFocus’s independent tests.
For a coding decision, use a fixed set of representative bugs from your own repository. Start each run from the same commit, provide the same instructions, and record whether the resulting change passes relevant tests and reviewer checks. Measure total cost and elapsed time, including unsuccessful attempts. For document analysis, prepare questions with known answers and ask for exact passages, then check whether the cited evidence supports the response.
Do not infer that an API model automatically includes a particular application’s repository access, browsing, or audio interface. Tools and permissions belong to the integration. For the practical product comparison, read Claude Code, Codex, and Gemini Code Assist workflows.
Which should you evaluate first?
- For an API project you can start now: compare Sonnet 5.5 and GPT-6.1 Sol on a small, measurable workload using your available accounts. Check current rate limits and applicable data policies before using business information.
- For an existing application: confirm which model and capabilities that application actually provides. A product subscription and an API account have separate terms.
For token rates, caching charges, and a transparent cost example, see our separate Sonnet 5.5, GPT-6.1 Sol, and Argon API pricing comparison.
Frequently asked questions
Is Gemini 4 Argon generally available?
The September 30 announcement describes limited Fairwind access and a wider release to follow. General availability is not established by that announcement.
Does a larger context window make a model more accurate?
No. Capacity and accuracy answer different questions. Test whether the model retrieves the information your task needs, handles conflicting passages, and supports its answer with correct evidence.
How this comparison was prepared
This AI-assisted article compares primary vendor documentation checked on October 1, 2026. GadgetsFocus did not conduct a hands-on benchmark of these three models for this article. The evaluation procedure above is suggested methodology, not a report of completed tests.
Correction, October 1: An earlier version included unsupported benchmark rankings and inaccurate context, pricing, and availability claims. Those claims have been removed or corrected. For a factual correction, use the GadgetsFocus contact page and include the passage and supporting source.
Featured artwork: Concept illustration of AI systems; it is not a hardware photograph or comparative benchmark.
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