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What Is Opus LLM? Claude Opus 5.5 Explained

Learn what “Opus LLM” refers to, what Claude Opus 5.5 is designed for, its stated API identifier and token prices, and what to test before choosing it for production.

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“Opus LLM” usually refers to Claude Opus, Anthropic’s line of large language models—not to a general AI technology or a single unchanging model. This guide focuses on Claude Opus 5.5, the specific version described in Anthropic’s product announcement. Anthropic positions it for agentic coding, computer use, and knowledge work. (Anthropic’s Opus 5.5 announcement)

An LLM, or large language model, is a type of deep-learning model trained on large amounts of data. “Opus” is Anthropic’s product name, not a technical model standard. Since capabilities and prices can differ by version, check which Opus release a specification refers to. (IBM’s LLM overview)

What Claude Opus 5.5 is suited for

Anthropic reports strengths in agentic coding, computer use, and knowledge work, including long codebase migrations, software debugging, business workflows, research, and financial analysis. For example, Anthropic says one early tester completed a 680,000-line code migration in less than a day. That is an attributed example, not a promise about your project. Anthropic also cautions that benchmark margins may not reliably predict real-world differences. (Anthropic’s Opus 5.5 announcement)

How to decide whether it fits

Test Opus on representative tasks from your own workload before making it your default. Use the prompts, tools, data, and success criteria you expect to use in production, then compare:

  • Quality: Did the result pass your tests, review rubric, or factual checks?
  • Reliability: Did it complete the task correctly across repeated runs and edge cases?
  • Latency: How long did the complete task take, including tool calls and retries?
  • Cost: What did the task cost after input, output, caching, and repeated calls?

Use benchmark and tester results as reasons to evaluate the model, not as guarantees of performance on your workload.

Opus 5.5 API identifier and pricing

Anthropic’s announcement gives the Claude Platform model identifier claude-opus-5-5 and says Opus 5.5 is available on the Claude Platform, Amazon Web Services, Google Cloud, and Microsoft Azure. It does not provide provider-specific setup instructions or establish that every provider uses the same identifier. (Anthropic’s Opus 5.5 announcement)

The announcement lists standard prices per 1 million tokens:

Token type Standard price per 1 million tokens
Input $4
Output $20
Cache reads $0.20
Cache writes $5

The announcement does not specify a duration for the cache-write rate. It separately lists fast mode in Claude Code and the Claude Platform at $8 per million input tokens and $40 per million output tokens, with output described as up to 2.5× faster. These are announcement-stated rates; confirm current pricing and applicable terms before budgeting. (Anthropic’s Opus 5.5 announcement)

The announcement gives a model identifier and prices, but it is not an API integration guide: it does not include an endpoint, authentication instructions, request or response examples, or SDK setup. Consult the Claude Platform API documentation for integration details.

Safeguards and production caveats

Anthropic says safeguards apply to cybersecurity and biology-related work, and that most cybersecurity tasks are rerouted to Opus 4.8. It describes a verification program for eligible biology research. Check current program status and eligibility if these restrictions matter to your use case. Anthropic also acknowledges limits in evaluating how models may behave in real-world settings. Model safeguards do not replace application-level security controls and testing. (Anthropic’s Opus 5.5 announcement)

Bottom line: “Opus LLM” generally points to Anthropic’s Claude Opus models; the facts here concern Claude Opus 5.5 specifically. Anthropic positions it for demanding coding, computer-use, and knowledge-work tasks. Its announcement provides a Claude Platform model ID and token prices, but choosing it for production requires workload-specific testing and confirmation of current pricing and operational terms.

Sources

Introducing Claude Opus 5.5 — Anthropic

What Are Large Language Models (LLMs)? — IBM

API overview — Claude Platform Docs

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