Sources checked September 24, 2026. This is a documentation-based guide, not a hands-on benchmark. Product access and limits can change.
Claude is Anthropic’s AI assistant and model family. The chat product, developer API and tools built around its models are related, but they are not interchangeable products. Begin by identifying whether you want help in a conversation or a model integrated into software.
Chat product or developer API?
The Claude getting-started guide is the appropriate starting point for the conversational product. Developers should use the model overview to confirm model identifiers, capabilities and platform availability.
At this source check, Anthropic’s model overview lists Claude Fable 5.1, Opus 5.5, Sonnet 5 and Haiku 4.5. This is an API-family reference, not a promise that every model appears in every consumer plan. Check your actual account before relying on a particular option.
What changed with Claude Opus 5.5?
Anthropic’s September 22 release notes announce Opus 5.5. The model documentation lists the API identifier claude-opus-5-5, a one-million-token context window and up to 128,000 output tokens. Standard API pricing is $4 per million input tokens and $20 per million output tokens; these are usage rates, not a Claude chat subscription price.
Developers should review migration compatibility before changing the model identifier: adaptive thinking cannot be disabled and forced tool use returns an error. That makes a small regression trial more useful than a blind version swap. Check tool calls, output parsing and error handling with your own saved examples.
For editor users, Cursor’s model list now includes Opus 5.5 with 300k default and 1M maximum context. Availability in a model list does not establish the allowance or settings in your account. No speed or quality improvement has been independently measured for this guide.
Your first useful session
- Pick one task with an answer you can judge, such as revising a short document without changing its facts.
- Supply the audience, purpose, constraints and desired output format.
- Separate reference material from your instructions. Explain which facts the answer must preserve.
- Ask for uncertainty to be stated explicitly rather than filled with guesses.
- Read the answer against your reference, then request one specific correction at a time.
For example: “Rewrite this announcement for new customers in 180 words. Preserve the launch date and eligibility rules. Flag any missing information instead of inventing it.” That prompt gives you a concrete basis for review.
Evaluate with known answers
For a summary, make a short checklist of essential points before submitting the source. For a research question, open the cited pages. For code, review the patch and run relevant checks. An articulate explanation can still be wrong.
Try a second task where the reference deliberately lacks one requested fact. A useful answer should identify the gap. Record the prompt, product, model shown and date so that future comparisons are meaningful.
Understand limits before committing
Inspect the current product and plan documentation for the workflow you need. Do not infer subscription limits from API context-window figures or API billing from a chat subscription. Check the exact platform and account configuration.
Before using business documents, determine whether the service and settings meet your organization’s requirements. Begin with non-sensitive sample material. Connected tools and repository access should receive their own review.
When to compare another assistant
If a task requires frequent correction, run the same prompt and reference through another candidate. Compare correctness, missing constraints and editing time. Keep the evaluation small and repeatable instead of switching on the strength of one impressive answer.
Our Claude versus ChatGPT guide explains a side-by-side workflow. The chatbot selection guide supplies a broader task scorecard.
Frequently asked questions
Is Claude a single model?
No. Anthropic documents a model family. Product names, model identifiers and plan entitlements should be checked separately.
Does this article contain a hands-on rating?
No. It is based on official documentation and suggested evaluation methods. No numerical performance rating is assigned.
What should I verify when a new version arrives?
Confirm availability in your product, rerun your saved tasks and note any change in cost, limits or output quality.
Sources
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