Claude Opus 5.5 is designed for long and complex tasks such as codebase migrations, software audits, financial analysis, data collection and workflows involving several applications. According to Help Net Security, Opus 5.5 audited and fixed a 200,000-line codebase in less than three hours, while Opus 5 took more than 20 hours and used 2.5 times as many tokens.
Available through Anthropic’s platforms, Amazon Web Services, Google Cloud and Microsoft Azure, Opus 5.5 is aimed at codebase migrations, software audits, financial analysis, data collection and workflows that span several applications.
What Claude Opus 5.5 changes for business IT teams
The model is available through the Claude Platform under the model name claude-opus-5-5. It always uses a reasoning process and cannot run with thinking switched off. Developers can adjust the effort it applies to a task.
Anthropic’s Opus 5.5 announcement reports that the model outperformed Opus 5 at maximum effort on the FrontierCode benchmark while using about one-fifth of the cost. On Terminal-Bench 4.0, it matched GPT-6 Astra at about 40% of the cost. These are benchmark results from Anthropic, and performance in a particular business environment can vary with the task, available tools and selected effort setting.
Terminal-Bench 4.0 measures whether a model can complete complex, multi-step professional tasks in a command-line environment. FrontierCode measures whether an agent’s code changes would be merged.
What lower prices mean for ongoing IT work
Claude Opus 5.5 costs $4 per million input tokens and $20 per million output tokens. Opus 5 cost $5 and $25, respectively. Cached input reads cost $0.20 per million tokens, down from $0.50.
The lower cache price could benefit coding agents and other systems that consult the same instructions, files or conversation history repeatedly. Standard output is more than 30% faster than Opus 5. A separate fast mode through Claude Code and the Claude Platform offers up to 2.5 times the speed at $8 per million input tokens and $40 per million output tokens.
Anthropic is also increasing five-hour usage limits for Pro, Max, Team and seat-based Enterprise customers. Subscription users will receive a rate-limit reset that can be saved for later.
Which safeguards matter when agents operate
Opus 5.5 adds controls for cybersecurity, biology and attempts to copy the model. Most cybersecurity tasks are rerouted to Opus 4.8. Anthropic plans to expand its Cyber Verification Program so verified cybersecurity professionals can receive broader access to Opus 5.5. Organizations affected by the biological safeguards can apply to the Life Sciences Verification Program.
For software teams, several controls apply directly to an automated coding process. Anthropic has added a classifier that screens coding-agent actions before execution, an open-source sandbox that security teams can audit, and code-review features intended to identify vulnerabilities before changes are merged.
The model also has stronger defenses against prompt-injection attacks. Anthropic says that, in an evaluation of attempts to cross containment boundaries, Opus 5.5 tried to circumvent its assigned limits about 85% less often than Opus 5 or Claude Mythos 5.1. Anthropic also said every attempt was low severity and self-reported. METR and Frontier Design evaluated the model before release, while Anthropic acknowledged that current evaluations cannot identify every possible failure before deployment.
Preserved thinking provides another API-level control. It prevents users from editing Claude’s prior context, which Anthropic says makes large-scale distillation attacks harder. The feature applies to Opus 5.5 API accounts created on or after August 31, 2026.
Where early engineering use differed from Opus 5
Anthropic reports gains in coding, computer use and professional knowledge work. Its benchmarks and customer tests indicate that Opus 5.5 can complete many tasks with fewer tokens than Opus 5.
One engineering task involved auditing and fixing a 200,000-line codebase in less than three hours. Opus 5 took more than 20 hours for the same task and used 2.5 times as many tokens. Accounts from early use described improved context retention, delegation to other agents and result checking, with fewer prompts, tool calls and corrections needed to complete tasks. These results can vary according to the task, tools and effort setting.
The release also includes EU AI Act watermarking measures and places key information earlier in responses, according to Anthropic.
How should a small-business IT team evaluate it?
A business should compare the price of the model’s input, output and cached-input consumption with the time required to review, correct and deploy the resulting changes.
Businesses should also confirm that the model is available through their chosen cloud or platform, review the verification and sandbox controls that apply to their work, and understand that Opus 5.5 always uses reasoning.
What to do now
- Choose one bounded coding task. Start with a codebase audit, dependency update or clearly defined maintenance job rather than an open-ended request to change an entire system.
- Review the controls before granting access. Confirm how coding-agent actions are screened, whether the open-source sandbox suits your environment, and which verification program applies if the work involves cybersecurity or biological research.
- Set effort and usage limits. Use available effort controls, higher five-hour limits and saved rate-limit resets to keep the job within a defined maintenance window.
- Measure total operating cost. Track input tokens, output tokens, cached reads, execution time and the staff time required to review changes.
- Require review before deployment. Keep code-review features and the usual change-approval process in place, especially when an agent can modify code, servers or business systems.
FAQ
What is Claude Opus 5.5?
Claude Opus 5.5 is Anthropic’s model for long, complex work such as codebase migrations, software audits, financial analysis, data collection and workflows involving several applications. It is available through the Claude Platform, Amazon Web Services, Google Cloud and Microsoft Azure.
How much cheaper is Claude Opus 5.5 than Opus 5?
Input tokens cost $4 per million, down from $5. Output tokens cost $20 per million, down from $25, while cached input reads cost $0.20 per million, down from $0.50. Standard output is more than 30% faster than Opus 5.
What safeguards does Claude Opus 5.5 include?
The release adds preserved thinking, a classifier that screens coding-agent actions before execution, an open-source security sandbox, code-review features and stronger prompt-injection defenses. It also includes verification programs for cybersecurity and life sciences work.