Claude Opus 5.5 is here: Anthropic claims it can finish a 680,000-line code migration in less than a day
&imwidth=600&imheight=450&format=webp&quality=medium "Claude Opus 5.5 is here: Anthropic claims it can finish a 680,000-line code migration in less than a day")
Claude Opus 5.5 is Anthropic’s new AI powerhouse: Here’s what it can do
Anthropic's Claude Opus 5.5 scored 66.4% on Terminal-Bench 4.0, ahead of OpenAI's GPT-6 Astra in company-reported results. The new model targets coding, computer use and AI agents, with Anthropic claiming 40% lower operating costs than Opus 5.
Anthropic has unveiled Claude Opus 5.5, the first model in its new Claude 5.5 family, as the AI race moves beyond chatbots towards systems that can write code, operate computers and complete complex tasks with less human supervision.
The company says Opus 5.5 scored 66.4% on the Terminal-Bench 4.0 coding benchmark, compared with 57.9% for OpenAI’s GPT-6 Astra and 55.8% for Anthropic’s own Claude Fable 5.1. Anthropic also claims the model can handle major software projects while costing 40% less to run than Opus 5.
Claude Opus 5.5 takes aim at OpenAI in coding
The biggest headline is its coding performance. Terminal-Bench 4.0 tests how well AI models complete complex, multi-step tasks using a command-line interface.
Anthropic's reported 66.4% score puts Opus 5.5 ahead of GPT-6 Astra and Fable 5.1 on this test. However, these are company-reported benchmark results, and Anthropic acknowledges that small score differences may not always translate into noticeable real-world advantages. The company says Opus 5.5 is particularly suited to large codebases, debugging, software migrations and code reviews. In one early test cited by Anthropic, the model completed a migration involving 680,000 lines of code in less than a day work the company says would have taken an engineering team weeks. It is a striking claim, although real-world performance will depend on the project, testing requirements and human oversight.
AI that can use computers and handle longer jobs
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Opus 5.5 is not limited to writing code. Anthropic says it has improved computer use, allowing the model to interact with digital interfaces and complete multi-step tasks. It is also designed for long-running AI agents that can plan work, use multiple tools and continue tasks with less supervision.
The model has a one-million-token context window, allowing it to process large amounts of information in a single context, and supports up to 128,000 output tokens.
Claude Platform Docs This could make it useful for developers working across large software projects and businesses handling complex knowledge-work tasks.
The surprising part: It costs less
Anthropic is also making a pricing play. Opus 5.5 costs $4 per million input tokens and $20 per million output tokens, compared with $5 and $25 respectively for Opus 5. The company estimates that typical workloads cost around 40% less, helped by both lower token prices and fewer tokens needed to complete tasks.
Anthropic
Claude Opus 5.5 is available through Claude's paid plans, the Claude API, Amazon Bedrock, Google Cloud and Microsoft Foundry.
Claude Platform Docs The launch adds another chapter to the competition between Anthropic and OpenAI. The bigger question is no longer just which AI can answer questions better, but which can reliably complete valuable work and do so at a cost businesses are willing to pay.
