Question 1

What is Claude Opus 5.5?

Accepted Answer

Claude Opus 5.5 is Anthropic’s flagship model in the Claude 5.5 family, released on September 22, 2026. Anthropic recommends it for long-running agentic coding and knowledge work. It has a 1M-token context window and up to 128K output tokens.

Question 2

How do I use Opus 5.5 on Runable?

Accepted Answer

Sign in to Runable, start a new task and choose Opus 5.5 in the model menu next to the prompt box. Then describe what you need, such as a website, a deck or a research report, and Runable runs the job on Opus 5.5.

Question 3

Do I need a Claude subscription or API key?

Accepted Answer

No. Opus 5.5 runs on your Runable plan and credits, so you do not need an Anthropic account or API key.

Question 4

Is Opus 5.5 better than GPT-6 Astra?

Accepted Answer

It depends on the task. In Anthropic’s published table, Opus 5.5 scores higher on Terminal-Bench 4.0, GDPval-AA and Humanity’s Last Exam, while GPT-6 Astra scores higher on Terminal-Bench Science and AutomationBench. Artificial Analysis ranked Opus 5.5 above Astra on its overall index in October 2026. On Runable you can try both on the same task.

Question 5

What is the difference between Opus 5.5 and Sonnet 5.5?

Accepted Answer

Both have a 1M-token context window. Opus 5.5 is Anthropic’s choice for complex, open-ended work. Sonnet 5.5 is faster and half the API price, and Anthropic says it comes within two points of Opus 5.5 on GDPval-AA, so it suits well-scoped everyday tasks.

Question 6

Is Opus 5.5 Anthropic’s most powerful model?

Accepted Answer

Not quite. Claude Fable 5.1 sits above it in Anthropic’s lineup, but Anthropic says Opus 5.5 performs at about Fable 5.1’s level on most work at a much lower cost, and Artificial Analysis ranked Opus 5.5 first on its index in October 2026.

Question 7

Can I turn off thinking on Opus 5.5?

Accepted Answer

No. Thinking is always on for Opus 5.5 and adapts to the difficulty of the task. If you want quicker, shorter answers, Sonnet 5.5 or Haiku 5.5 are better picks.

Question 8

What can I make with Opus 5.5 on Runable?

Accepted Answer

Websites and web apps, slide decks, research reports, documents, spreadsheets and dashboards, social carousels, and multi-step workflows. Runable gives the model a browser, a code sandbox and publishing tools to finish the job.

Model	Best for	Speed	API price in / out
Opus 5.5	Long, complex agent work	96 tokens/s	$4 / $20
Sonnet 5.5	Everyday tasks, best speed for the smarts	134 tokens/s	$2 / $10
Haiku 5.5	High-volume, quick tasks	235 tokens/s	$0.10 / $0.50 *

Claude Opus 5.5

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Opus 5.5 on Runable

Finished work, not answers

Built for long jobs

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How to use Opus 5.5 on Runable

Select Opus 5.5

Describe the job

Edit and ship

One prompt, finished work

Why choose Opus 5.5

Top of the rankings

Fable-level, for less

Real knowledge work

Agentic coding

Huge context

Thinks first

Opus 5.5 specs

Opus vs Sonnet vs Haiku 5.5

The only AI agent you need

Opus 5.5 FAQs

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