Claude Opus 5.5
Anthropic · released Sep 22, 2026
- Type
- Closed
- Input
- $4.00
- Output
- $20.00
- Cached
- $0.20
List price · per 1M tokens · Anthropic at 1M context · machine-readable source ↗
Our take
Written Oct 1, 2026Claude Opus 5.5 is a hosted-only model that leads the Arena boards for general chat and creative writing, and ranks near the top on mathematics. Those Arena placings are human preference votes rather than correctness, and constrained instruction following is its weakest measured category.
Reach for it on work where people judge the answer — drafting, rewriting, open-ended chat — and on competition-style mathematics, where it ranks first of 58 on LiveBench Mathematics via Max effort as of 25 Jun 2026. It takes images and files alongside text, so a screenshot or a document does not have to be described in words first. Skip it if you need to run the model on your own hardware, or if constrained instruction following is the job.
The case for it
- First of 168 on Arena Text (overall) via High as of 25 Sep 2026 and first of 168 on Arena Creative Writing via High as of 25 Sep 2026 — both record which answer people preferred, not whether it was correct.
- First of 58 on LiveBench Mathematics via Max effort as of 25 Jun 2026, covering competition and olympiad maths.
- Third of 168 on Arena Coding via High as of 25 Sep 2026 and second of 58 on LiveBench Coding via Max effort as of 25 Jun 2026, so coding is measured well on both boards.
- Second of 58 on LiveBench Agentic Coding via Max effort as of 25 Jun 2026, a result for the model inside an agent harness rather than standalone.
The case against it
- Thirty-third of 58 on LiveBench Instruction Following via xHigh effort as of 25 Jun 2026, covering constrained-rewriting tasks — far below its placings on the other LiveBench boards.
- We list no download for it, so using it means choosing a host and paying per token.
- The Arena placings are preference votes: they say nothing about factual accuracy or fitness for a specific task.
How good is it?
A closed text model from Anthropic for everyday questions, drafting and coding, with no weak spots flagged on the board.
- getting answers to everyday questionsArena Text (overall) · 1st of 168
- drafts, rewrites and editingArena Creative Writing · 1st of 168
- writing and completing codeArena Coding · 3rd of 168
EverydayGeneral questions and everyday reasoning
Arena Text (overall)1st of 168 · 1509
CodingWriting and fixing code on its own
Arena Coding3rd of 168 · 1547
AgenticPlanning, calling tools, staying on task
Not yet scored on Arena Agent. It is on LiveBench Agentic Coding, in 2nd of 58 with 71.72.
WritingDrafting and rewriting prose
Arena Creative Writing1st of 168 · 1521
Boards this model appears on that none of the ratings above are built on.
Every published score for this model14 scoresEvery figure we hold, from 14 boards, with who ran it and a link to the source — including the boards no rating above is built on.
Where to rent it
Prices checked 4 hours ago — each listing carries its own date.
Anthropic, direct
The lab is also the cheapest we hold. The strip above and this offer are the same one, so nothing on this page undercuts Anthropic on 1M of context.
- per 1M tokens
- $4.00 in / $20.00 out
- Context served
- 1M
- Throughput
- ~70 tok/s
| Provider | In / out per 1M tokens | Context | Throughput | Trains on prompts | Logs prompts | Zero retention |
|---|---|---|---|---|---|---|
| OpenRouterOpenRouter's own listing | $4.00 / $20.00checked 4 hours ago | 1M | not measured | Unknown | Unknown | Unknown |
| DeepInfraDirect | $4.00 / $20.00checked 4 hours ago | 1M | not measured | Unknown | Unknown | Unknown |
| Microsoft Azure AIglobalThrough OpenRouter | $4.00 / $20.00checked 4 hours ago | 1M128K max reply | 66 tok/s | No | No | Unknown |
| Google Vertex AIglobalThrough OpenRouter | $4.00 / $20.00checked 4 hours ago | 1M128K max reply | 77 tok/s | No | No | Confirmed |
| AnthropicDirect | $4.00 / $20.00checked 4 hours ago | 1M128K max reply | 70 tok/s | No | Yes30 days | Unknown |
| Amazon BedrockThrough OpenRouter | $4.00 / $20.00checked 4 hours ago | 1M128K max reply | 54 tok/s | No | No | Confirmed |
| Claude Platform on AWSThrough OpenRouter | $4.00 / $20.00checked 4 hours ago | 1M128K max reply | 61 tok/s | No | Yes30 days | Unknown |
| Amazon Bedrockeu-west-1Through OpenRouter | $4.40 / $22.00checked 4 hours ago | 1M128K max reply | 72 tok/s | No | No | Confirmed |
| Microsoft Azure AIusThrough OpenRouter | $4.40 / $22.00checked 4 hours ago | 1M128K max reply | 8 tok/s | No | No | Unknown |
| Amazon Bedrockus-east-1Through OpenRouter | $4.40 / $22.00checked 4 hours ago | 1M128K max reply | 49 tok/s | No | No | Confirmed |
| Google Vertex AIusThrough OpenRouter | $4.40 / $22.00checked 4 hours ago | 1M128K max reply | 81 tok/s | No | No | Confirmed |
| Google Vertex AIeuropeThrough OpenRouter | $4.40 / $22.00checked 4 hours ago | 1M128K max reply | 82 tok/s | No | No | Confirmed |
| Anthropicfast tierThrough OpenRouter | $8.00 / $40.00checked 4 hours ago | 1M128K max reply | 100 tok/s | No | Yes30 days | Unknown |
OpenRouter
DeepInfra
Microsoft Azure AI
Google Vertex AI
Amazon BedrockAcross the 13 listings we hold: 11 say they do not train on prompts, 0 say they do and 2 do not say. 6 appear in the zero-retention registry we check; the rest are unknown to us.
What each host's API supports
From the parameter list each endpoint publishes. Streaming is omitted: nothing we hold reports it, for any model.
| Provider | Tool calling | JSON output | Strict schema |
|---|---|---|---|
| OpenRouterOpenRouter's own listing | ✓ | ✓ | ✓ |
| DeepInfraDirect | |||
| Microsoft Azure AIglobalThrough OpenRouter | ✓ | ✓ | ✓ |
| Google Vertex AIglobalThrough OpenRouter | ✓ | ✓ | ✓ |
| AnthropicDirect | ✓ | ✓ | ✓ |
| Amazon BedrockThrough OpenRouter | ✓ | ✓ | ✗ |
| Claude Platform on AWSThrough OpenRouter | ✓ | ✓ | ✓ |
| Amazon Bedrockeu-west-1Through OpenRouter | ✓ | ✓ | ✗ |
| Microsoft Azure AIusThrough OpenRouter | ✓ | ✓ | ✓ |
| Amazon Bedrockus-east-1Through OpenRouter | ✓ | ✓ | ✗ |
| Google Vertex AIusThrough OpenRouter | ✓ | ✓ | ✓ |
| Google Vertex AIeuropeThrough OpenRouter | ✓ | ✓ | ✓ |
| AnthropicfastThrough OpenRouter | ✓ | ✓ | ✓ |
Tool calling: 12 of 13 listings say yes, 1 publishes no parameter list. JSON output: 12 of 13 listings say yes, 1 publishes no parameter list. Strict schema: 9 of 13 listings say yes, 3 say no, 1 publishes no parameter list.
Models people weigh against Claude Opus 5.5
When we formed this view
Recent changes
What moved
first indexed by our pipelineEach date is the day we first saw the change, or the day the maker announced it.
What we do not know about this model yet
- 1 of 13 listings publishes no parameter list, so what its API accepts is unknown to us.
- Nothing we hold says whether an endpoint streams, so we do not show it either way.
- 2 of 13 listings do not say whether they train on prompts.
- We hold no batch or off-peak rate for any of its listings.
Licence and identifiers
What the licence allowsWe hold no licence record for this model. Inside are the identifiers you need to pull it — its Hugging Face repo where we have one, our slug and a machine-readable card.
Licence
We hold no licence record for this model, and no record of published weights either — so we can neither summarise its terms nor point you at the weights.
Identifiers
- Takes in, gives back
- Text, images and documents in, text out
- Catalogue slug
- anthropic-claude-opus-5-5