News/Models
Try nowModels·MeaningfulOfficialstableUpdated Oct 8·Updated 2×·Event Sep 28, 2026·First seen Oct 9
Anthropic Launches Claude Opus 5.5 for High-End Reasoning and Research
LaunchTrending
Try it
Something you can actually use or run today.
On September 28, 2026, Anthropic released Claude Sonnet 5.5, an upgrade delivering 30% higher speeds and 30% lower costs.
The update reinforces Anthropic's lead in 'reasoning-per-dollar,' specifically for creative and professional coding tasks.
AILookup take
Anthropic's 5.5 cycle is less about a massive leap in raw intelligence and more about refining the 'vibes' and reliability of the model. Sonnet 5.5 remains the current favorite for coding agents due to its lower hallucination rate in complex file structures.
Who cares
professional software engineersAI researcherspower users
Watch next
Performance degradation reports as Anthropic likely applies more aggressive safety filters post-launch.
Details
- Sets a new high bar for complex reasoning tasks that previous models struggled with.
- Enables longer-running autonomous agent workflows for research.
- Early testers report high success in complex multi-hour creative coding tasks.
Consensus
Opus 5.5 is currently the top performer for deep reasoning over long context windows.
Related articles (6)
17h agoHacker NewsI gave Opus 5.5 one prompt and six hours to visualize Invisible Cities3d agoAWS ML BlogSupercharge regulated workloads with Claude Code and Amazon BedrockSep 28Simon WillisonClaude Sonnet 5.5Sep 28Anthropic BlogIntroducing Claude Sonnet 5.5Sep 24YouTube: Two Minute PapersClaude Opus 5.5 AI: A Massive Leap ForwardSep 22Anthropic BlogIntroducing Claude Opus 5.5
Introducing Claude Sonnet 5.5Hacker NewsAWS ML BlogSimon WillisonAnthropic BlogYouTube: Two Minute Papers· 6 stories
More in Models
Google Launches Embeddinggemma 2 for Natively Multimodal Embeddings4 sources · Oct 8Google DeepMind Launches Gemini 4 Argon for Cyber Defense and Enterprise Applications8 sources · Oct 8Anthropic Releases Claude Haiku 5.5 for High-Volume Cost-Sensitive Tasks2 sources · Oct 7Strands Agents Releases Strands Decider 2b Decision Model1 source · Oct 7Mistral AI Launches Mistral Large 4 Flagship Model to Challenge Frontier Rivals5 sources · Oct 7