Claude Opus 5.5
Anthropic's thoughtful all-rounder for careful writing and analysis, the highest-ranked Claude on the arena.ai Text Arena, available anonymized through NeverNo.
Updated November 10, 2026
Readable on your devices only.
Your conversation is readable on your device, and on your other devices if you sync them. Nowhere else.
Unreadable to us.
Your message passes through without being written down; your chats are only ever stored encrypted.
The model doesn’t know you.
It gets the question, never your email, your account or your IP address.
Nothing is left along the way.
The reply comes back and is stored here, encrypted; even when you sync, your key never reaches us in the clear.
At a glance
| Maker | Anthropic |
|---|---|
| Context | 200,000 tokens |
| Longest reply | 16,384 tokens |
| Strengths in the app | Hard questions, Reasoning, Reads images |
| Reasoning | Always on |
| Who can use it | Paid plans |
| How it’s paid | Credits, from the first use |
| Privacy | Anonymized: NeverNo sends the request to its maker without your name, account or IP address. The maker still reads the text, applies its own rules and may keep it for a while under its own policy.Some requests its maker doesn’t allow are answered by one of NeverNo’s private models instead, and the app tells you so. |
Price
What the app charges, read from the same table the servers bill with. 1 credit = $0.01.
| Typical message (2,000 tokens read, 600 written) | 5.28 credits ($0.0528) |
|---|---|
| Million tokens read | 1,055 credits ($10.55) |
| Million tokens written | 5,275 credits ($52.75) |
Measured
Our own measurements and one third-party score, each with its conditions and date. Figures are not rounded.
| Median time to the first word | 2.35 sOur client, 12 everyday requests run 3 times each, November 9, 2026 |
|---|---|
| arena.ai Text Arena, overall score | 1,509Third-party leaderboard, page dated October 27, 2026 |
What it is
Claude Opus 5.5 is one of Anthropic's large models, and on NeverNo it is the Claude we suggest for work where quality of judgment and quality of prose both matter: a report that must read well and hold up, a delicate message, a dense document to digest, a decision with trade-offs, a translation where register and idiom matter. It reasons on every request, and the selector offers no level to tune: the model decides how long to think.
Access is anonymized. NeverNo sends your request to Anthropic without your name, your account or your IP address, and your conversation history stays encrypted in your browser rather than on our servers. Anthropic still reads what it receives, applies its own usage rules and may keep the request for a while under its own policy, so Opus may decline some requests. Some requests its maker does not allow are answered by one of NeverNo's private models instead, and the app tells you so.
On the arena.ai Text Arena (overall score, page dated October 27, 2026), Claude Opus 5.5 scores 1509: ahead of Claude Sonnet 5.5 (1477) and of Claude Fable 5.1 (1504), the previous version of Fable (Claude Fable 5.2, which replaced it on November 10, 2026, has no score yet), and second among our catalog models with a score, behind Gemini 4 Argon (1520). That arena measures how often people prefer a model's answers in open conversation, which matches where Opus shines: nuanced explanations, well-structured prose and replies that anticipate the follow-up question.
Opus 5.5 takes 200,000 tokens of context, writes up to 16,384 tokens per answer and reads images. It is a premium model on paid plans, paid in credits per message; it costs fewer credits than Fable 5.2 and more than Sonnet 5.5.
Strengths
The best-scored Claude on the arena.ai Text Arena: 1509 on October 27, 2026, a signal that people tend to prefer its answers in open-ended conversation.
Writing with nuance: long-form texts, tone-sensitive emails, summaries that keep the important caveats instead of flattening them.
Always reasons before answering, which helps on judgment calls, trade-offs and questions with no single right answer.
Reads images and holds 200,000 tokens: a long document plus its charts or scanned annexes fit in a single conversation.
Anonymized access: no Anthropic account to create, no identity forwarded, history encrypted on your own device.
Limits
Every message costs credits on a paid plan; for routine questions, Claude Sonnet 5.5 or an included private model will do the job for less.
Reasoning cannot be turned off or shortened, so quick back-and-forth feels slower than with Claude Haiku 5.5.
It is not tagged for code in our selector: for programming, Claude Sonnet 5.5 or Claude Fable 5.2 are the Claude models to choose.
Anthropic reads the text and applies its own rules, so it can refuse; some requests outside those rules go to a private NeverNo model, and the app says so.
When to choose it
Writing that has to land
A grant application, a eulogy, a resignation letter, the opening of a keynote, a sensitive reply to a client: describe the reader and the stakes, and Opus drafts text that is clear, measured and in the right register, then revises it on request.
Digesting a dense document
Feed it a research paper, a regulation, a court ruling or a long contract with its tables, and ask for the key findings, what is new, what is ambiguous and what it would ask the author. It keeps nuance where a shorter summary would lose it, and will flag the passages worth reading yourself before you quote or sign anything.
Thinking through a decision
Lay out the options, constraints and what you fear, and ask Opus to argue each side before giving a recommendation. Its reasoning spells out the trade-offs rather than handing you a bare verdict, and you can push back on any step you disagree with.
Prompt tips
Describe your audience and purpose, not just the topic: « for a board that has ten minutes and is skeptical » gives Opus far more to work with than « write a summary ».
Share examples of the tone you admire, even a paragraph of your own writing; it picks up voice and rhythm from samples remarkably well.
For decisions, ask it to argue against its own first recommendation before concluding; the second pass is often where the useful insight appears. Then ask which piece of missing information would most change its mind.
Frequently asked questions
Is Claude Opus 5.5 free on NeverNo?
No. Claude Opus 5.5 is a premium model on paid plans and is paid in credits for each message. An estimate for a typical exchange is displayed in the model selector.
Is Claude Opus 5.5 private when used through NeverNo?
It is anonymized. Anthropic receives your text without your name, account or IP address, and NeverNo keeps your history encrypted in your browser, not on a server. Anthropic still reads the request, applies its own rules and may keep it for a while. For a conversation that stays away from closed companies, choose one of NeverNo's private models.
How large is Claude Opus 5.5's context window?
200,000 tokens, with answers of up to 16,384 tokens. You can also attach images to your messages.
Claude Opus 5.5 or Claude Sonnet 5.5: which one should I choose?
Opus 5.5 scored higher on the arena.ai Text Arena (1509 versus 1477, October 27, 2026) and suits careful writing and analysis. Sonnet 5.5 costs fewer credits, lets you raise its reasoning effort and is tagged for code. For daily work and programming, Sonnet; for the texts and decisions that matter most, Opus.
How do I use Claude Opus 5.5 without an Anthropic subscription?
Take a paid NeverNo plan, open a chat and pick Claude Opus 5.5 in the model selector. NeverNo relays your messages without your identity; there is no Anthropic account or separate subscription involved.