Anthropic Claude Update Version Claude Opus 5.5

Claude Opus 5.5 is the first model in the Claude 5.5 family. It improves performance, safety, and writing quality, costs 40% less than Opus 5, and adds stronger safeguards for cybersecurity and biology.

• Stronger resistance to prompt injection and other misaligned behavior than Opus 5, with improved alignment audit results.
• Launches with safeguards similar to Claude Fable 5.1 for cybersecurity, biology, and distillation; most cybersecurity tasks are re-routed to Opus 4.8.
• Includes preserved thinking anti-distillation protection for API accounts created on or after Aug 31, 2026.

• Introduces Claude Opus 5.5, the first model in the new Claude 5.5 family.
• Adds fast mode for Opus 5.5 in Claude Code and the Claude Platform with up to 2.5x speed.
• Increases five-hour usage limits on Pro, Max, Team, and seat-based Enterprise plans.
• Provides subscription users a rate limit reset that can be saved and used later.

• The model still has limits in alignment testing, and evaluation may not fully predict real-world behavior.
• Some cybersecurity and biology tasks are transparently routed to fallback models because of safeguards.

• Available on all platforms, including AWS, Google Cloud, and Microsoft Azure.
• Zero data retention is available.
• Opus 5.5 is no longer available with thinking mode switched off.
• Vetted organizations can apply to the Life Sciences Verification Program; verified cybersecurity practitioners will be able to use the expanded Cyber Verification Program in the coming weeks.

• Blog post introducing Claude Opus 5.5
  https://www.anthropic.com/news/introducing-claude-opus-5-5

Product Information

Vendor: Anthropic

Product: Claude

Product type: Other

Platform: Web

Version: Claude Opus 5.5

Vendor information published: Sep 22, 2026

Original release notes: View on vendor site

Published on updatealert.io: Sep 24, 2026

Description: AI assistant for drafting, analysis, coding, and enterprise workflows.