Claude Opus 5.5 was released on 22 September 2026, so less than a month has passed. This article therefore combines verified specifications and prices from Anthropic's documentation (status on 20 October 2026) with what Reddit is discussing and with my own short but concrete experience: Opus 5.5 wrote the Blender scripts behind the 3D models in my own work-in-progress game Noční linka (Night Line).
Claude Opus 5.5 (API ID claude-opus-5-5, released 22 September 2026) costs $4 per million input tokens and $20 per million output tokens, a fifth less than Opus 5 ($5 / $25). It has a 1 million token context, output up to 128 thousand tokens and always-on adaptive thinking that cannot be turned off. Anthropic says it costs 40% less than Opus 5 on typical workloads and performs at the level of the pricier Fable 5.1 on most work. These figures come from the vendor.
- Models for my game. I am making my own game, Noční linka (alpha, unreleased). Its 3D models, meaning panel blocks, village houses, a train, cars, a bus, street furniture, a mill and a gamekeeper's lodge, were written by Opus 5.5 as Python scripts for Blender. Blender 4.1.1 ran windowless from the command line, with no Blender MCP.
- Where it fell short. An independent audit by GPT-6 Astra criticised bare sides and flat doors on the village houses and repeated stains on the train and the mill. That is why I judge the result from the render, not from the author's claims.
- What I do not have. I did not run a direct comparison of Opus 5.5 and Astra on the same task.
What is new compared with Opus 5?
According to Anthropic's announcement, Opus 5.5 is a major step up from Opus 5, it is cheaper, and its thinking cannot be switched off. I checked this on 20 October 2026 in the models overview and on the pages for Opus 5.5 and Opus 5.
| Parameter | Opus 5 | Opus 5.5 |
|---|---|---|
| Released | 24 July 2026 | 22 September 2026 |
| Input / output per 1M tokens | $5 / $25 | $4 / $20 |
| Context, maximum output | 1M, 128 thousand tokens | 1M, 128 thousand tokens |
| Thinking | adaptive, can be turned off at effort high or lower | adaptive, always on |
| Default effort | high | medium |
| Fast mode | research preview | generally available |
Opus 5.5 runs on the same clouds as Opus 5 (Claude API, Amazon Bedrock, Google Cloud, Microsoft Foundry). Alongside it, Anthropic is raising five-hour usage limits on the Pro, Max, Team and seat-based Enterprise plans.
For developers: a request with thinking disabled, or with forced tool use (tool_choice set to any or tool), returns a 400 error. The documentation What's new in Opus 5.5 also says the model thinks more per turn than Opus 5 at the same effort, most of all at xhigh and max.
How much does Claude Opus 5.5 cost and how is the price calculated?
Through the API it costs $4 per million input tokens and $20 per million output tokens. Cache reads cost $0.20, cache writes $5 (5 minutes) or $8 (one hour), and batch processing is half price. Fast mode (up to 2.5 times faster output according to the documentation) costs $8 / $40, exactly double. Source: Anthropic pricing, verified 20 October 2026. A subscription is consumed differently, see my article on credits and resets.
Worked example (a model calculation, not a measurement): an agentic coding task with 100,000 new input tokens, 400,000 tokens read from cache and 30,000 output tokens, with no cache writes and no fast mode. Opus 5.5: 100,000 × $4 / 1M = $0.40, 400,000 × $0.20 / 1M = $0.08 and 30,000 × $20 / 1M = $0.60, $1.08 in total.
| Model (same token counts) | Task cost |
|---|---|
| Sonnet 5.5 ($2 / $10) | $0.54 |
| Opus 5.5 ($4 / $20) | $1.08 |
| Opus 5 ($5 / $25) | $1.45 |
| Fable 5.1 ($10 / $50) | $2.60 |
With the same token counts, Opus 5.5 is about a quarter cheaper than Opus 5. Anthropic states 40% for typical workloads; the rest would have to come from different token consumption, which I did not measure. Models also do not use the same number of tokens: a pricier one may finish in fewer attempts, a cheaper one may need corrections.
How does Opus 5.5 do in benchmarks and why not trust them blindly?
Results from the Anthropic announcement. Unless the vendor says otherwise, they use adaptive thinking at maximum effort.
| Test | Opus 5.5 | Fable 5.1 | GPT-6 Astra | Opus 5 |
|---|---|---|---|---|
Terminal-Bench 4.0 |
66.4% |
55.8% |
57.9% |
52.3% |
FrontierCode v1.1 |
54.4% |
50.3% |
53.3% |
48.0% |
OSWorld 2.1 (partial) |
81.8% |
80.7% |
not reported |
74.0% |
AutomationBench |
40.0% |
31.4% |
41.4% |
26.9% |
Terminal-Bench-Science 0.1 |
58.7% |
52.6% |
64.6% |
29.0% |
This is not an independent test, and the notes under the results call for caution:
- Different settings. On Terminal-Bench 4.0, Opus 5.5 ran at xhigh and Astra at high (as reported by OpenAI), each with its best result.
- Different sources. On AutomationBench, the Opus 5.5 result comes from an early Zapier evaluation, the others from the public leaderboard. On Terminal-Bench-Science the error is 3.5 to 5 points per model, and the gap to Astra is 5.9 points.
- Safeguards. Opus 5.5 was tested with its safeguards on: cybersecurity tasks were completed by Opus 4.8 and biology tasks by Opus 5, which Anthropic says likely lowers its score.
Anthropic itself writes that, in its own use, the gap between Opus 5.5 and Fable 5.1 is narrower than the numbers suggest. Opus 5.5 leads three tests and Astra two, with gaps of a few points. I would not adopt the ranking from the table: what decides is the same task on your data and a check of the result.
What is Reddit saying about Claude Opus 5.5?
On 20 October 2026 I went through Google results in the built-in browser for the query site:reddit.com "opus 5.5" (last month). I did not open the threads themselves. I am working from the titles, snippets and comment counts the search shows, so this is a sense of the discussion, not data. Comment counts are rounded the way Google displays them.
- Opus 5.5 is the beginning of a new era, r/ClaudeCode, 1,100+ comments: the busiest of the threads. The snippet is a reply praising Opus 5.5 for showing good "instinct" and software engineering principles in practice.
- Is Opus 5.5 really better than Fable in your experience?, r/ClaudeCode, 150+ comments: the author has not tested the model yet and asks others. The reply Google shows reports a similar result but more efficient, with no session-limit problems so far.
- Opus 5.5 v/s Astra 6, r/ClaudeAI, 90+ comments: the snippet sums up that Opus 5.5 uses limits far more sparingly (hours of work on the $20 Pro plan), while Astra, it says, consumes a lot of tokens.
- Opus 5.5: First impressions by a trained philosopher, r/ClaudeAI, 200+ comments: an impression from conversation, not code. According to the snippet the model is more balanced, torn between being useful and a new, more agreeable nature.
- What's happening with Opus 5.5???, r/Anthropic, 120+ comments: a few days ago the author shared a showcase of a big project finished with the model and now asks what is happening with it. I cannot tell from the snippet what exactly bothers them.
- Opus 5.5: is it really a game changer for coding?, r/OpenAI, 90+ comments: a long-time OpenAI user weighs a switch. The reply Google shows is sceptical: every month some model is called a "game changer".
Three themes repeat: limit consumption (the second and third threads), comparisons with Fable 5.1 and Astra, and caution about the enthusiasm (the fifth and sixth threads). The claims about gentler limits are users' impressions, and I did not measure them myself. That the model thinks more per turn than Opus 5 at the same effort is confirmed by the documentation. Botmonster and The Daily Claude summarise similar themes, but those are secondary sources and I did not verify the threads behind them.
What is discussed about Opus 5.5 in Blender?
I went through Google results for Blender in the same way, with the searches site:reddit.com claude blender and site:reddit.com blender mcp (20 October 2026, titles, snippets and comment counts only). A selection:
- Has anyone tried Opus 5.5 with Blender MCP? How does it …, r/claude, 10+ comments: the asker wants experiences. The reply Google shows says the model is now roughly on par with Astra and gives solid results, supposedly worse before.
- Claude Opus 5.5 vs GPT-6 Astra for Rigging and Animating in 3D, r/TopologyAI, 30+ comments: the snippet is a comment praising Astra in Blender because, it says, it imagines a world in 3D and then writes a script that builds it.
- Opus 5.5 Max blender demo, r/ClaudeCode, 10+ comments: the snippet says Opus 5.5 takes 3D model generation and output quality to a different level. That is the thread author's claim, and I have not seen the result.
- Astra Comparison Python Script in Blender vs Blender MCP, r/aigamedev, Google does not show a comment count: judging by the title, it compares a script with MCP. I cannot read the result from the snippet.
My own experience is only with scripts and no MCP (see below), and I did not compare Opus 5.5 with Astra on the same task in Blender. I therefore do not adopt any ranking from the threads.
How do I use Claude Opus 5.5?
Agentic work in Claude Code. I have my own library of rules and roles (author, judge, tester), where the judge assesses the result, not the author's claims. The model reads SEO data (Search Console and a crawl through my tool SEO Radar) and works with other agents, for example Codex. I do not give savings figures because I did not measure them. Why the surrounding setup matters as much as the model is explained in my article on the harness.
3D models for a game as Blender scripts. Noční linka is my own work-in-progress game (alpha, not released): a night bus on line 913 in the Bořín district in the 1990s. It runs on Godot 4.7.1 and third-party assets are CC0 only. The 3D models of the world, meaning panel blocks, village houses, a train, cars, a bus, street furniture, a mill and a gamekeeper's lodge, were written by Opus 5.5 as Python scripts (bpy) for Blender. The commits are from 7 and 9 October 2026. Blender 4.1.1 ran windowless from the command line, rendering with Cycles on the CPU, with no Blender MCP and no text-to-3D generator. The model source is a readable script, so one flawed detail can be fixed without regenerating the whole scene. These are prototype-level game models. I have no first-hand experience with Blender MCP, so I do not judge it.
An independent critic. I do not let Opus judge its own models. In an audit on 10 and 11 October 2026, GPT-6 Astra reviewed them. On the bus it praised the readable silhouette, frames, handrails and seats. On the village houses it criticised bare sides and backs, flat doors and roofs that are too regular, looking like a construction kit up close. On the panel blocks, the train and the mill it criticised repeating dirt and stains. I did not run a direct Astra versus Opus comparison on the same task, so I do not claim one is better: they simply play different roles, author and independent critic. Details are in the article GPT-6 Astra.
When does Opus 5.5 not make sense?
- Simple bulk work. For classification, extraction and routing Anthropic recommends Haiku 5.5 (from $0.10 / $0.50, for prompts up to 100,000 tokens) and Sonnet 5.5 ($2 / $10) for everyday work. Haiku is about 40 times cheaper per token than Opus 5.5.
- Trivial tasks. Thinking cannot be turned off, so you can lower the bill only with lower effort or a smaller model.
- Cybersecurity and biology. Most cybersecurity tasks are rerouted to Opus 4.8 and biology requires verification (the Life Sciences Verification Program). Expect refusals.
- The hardest work. When Opus 5.5 falls short even at higher effort, Anthropic recommends Fable 5.1.
Which model to pick across ChatGPT, Claude and Gemini is covered in ChatGPT, Claude, Gemini and Kimi: which AI to choose.
If you want to bring Claude or another model into your company, I will show you on your own tasks which model and effort make sense in AI training. Connecting a model to your processes and tools is part of AI automation.
FAQ
How much does Claude Opus 5.5 cost?
Through the API, $4 per million input tokens and $20 per million output tokens, cache reads $0.20, batches half price, fast mode $8 / $40 (verified 20 October 2026). A Pro or Max subscription is a flat fee with usage limits. The cost of a task depends on the tokens consumed, not only on the price list.
Is Opus 5.5 free?
Not through the API, which is billed per token. In the Claude app, Anthropic's pricing page does not include Opus on the free plan, but does on Pro, Max, Team and Enterprise (the plan table does not state a version number, status 20 October 2026). Check the offer in your own account.
Opus 5.5 or Fable 5.1?
Fable 5.1 costs $10 / $50, 2.5 times more than Opus 5.5. Anthropic recommends starting with Opus 5.5 and reaching for Fable 5.1 for the most demanding reasoning and long agentic tasks, or when Opus 5.5 falls short even at higher effort. This article contains no comparison of my own with Fable 5.1.
Opus 5.5 or GPT-6 Astra?
Astra costs $10 / $50 and has a 1.05 million token context. In the table above, Opus 5.5 leads on Terminal-Bench 4.0 and FrontierCode, Astra on AutomationBench and Terminal-Bench-Science, and Astra has no OSWorld result. The figures come from the vendor. I did not compare them on the same task: in my game Opus built the models and Astra reviewed them.
What does Reddit say about Claude Opus 5.5?
The most visible threads discuss efficiency and limit consumption, comparisons with Fable 5.1 and GPT-6 Astra, and caution about the enthusiasm. I am working from Google search snippets of 20 October 2026, not from threads I have read, so this is a sense of the discussion, not a measurement. The links to individual threads are above.
Can thinking be turned off?
No. On Opus 5.5 adaptive thinking is always on, and a request with thinking: disabled returns a 400 error. You control depth with the effort parameter (default medium).
Sources and links
- Anthropic: Claude Opus 5.5, announcement and benchmarks
- Claude Docs: models, pricing and fast mode
- OpenAI: GPT-6 Astra, price and context