Anthropic release ‘Sonnet 4.6’

In a major update to its “workhorse” model family, Anthropic officially released Claude Sonnet 4.6 on February 17, 2026. This release marks Anthropic’s transition into the “Thinking” era, positioning Sonnet 4.6 as a model that approaches the intelligence of the flagship Opus 4.6 while remaining significantly faster and more cost-effective.

The headline feature of this version is the introduction of a 1 million token context window (currently in beta), allowing developers to feed entire multi-file codebases or dozens of research papers into a single prompt.

Performance Benchmarks: A New Standard for Agents

Sonnet 4.6 has shown massive gains over its predecessor, Sonnet 4.5, particularly in autonomous “computer use” and complex software engineering tasks.

Key Capabilities and Features

Anthropic has focused on making Sonnet 4.6 a “production-grade” model for autonomous agents.

1. 1M Token Context (Beta): Large enough to handle hundreds of pages of technical documentation or a massive codebase without losing track of details.
2. Native Code Execution for Search: When using web search, the model now automatically writes and executes Python code to filter and process results, ensuring only the most relevant data is kept in context.
3. Adaptive & Extended Thinking: On the developer platform, users can now toggle between “near-instant” responses and a mode where the model performs deep, step-by-step reasoning before answering.
4. Context Compaction (Beta): A new feature that automatically summarizes older parts of a conversation as it approaches the token limit, effectively extending the conversation’s life.
5. Agentic Computer Use: Improved precision in clicking, typing, and navigating digital environments, enabling the automation of procurement, CRM coordination, and customer onboarding.

Pricing and Availability

Despite the performance leap, Anthropic has kept pricing consistent with previous Sonnet generations.

• Pricing: $3.00 per million input tokens / $15.00 per million output tokens.
• Access Points: * Web/Mobile: Now the default model for Claude.ai (Free and Pro) and Claude Cowork.
  • Developer Platform: Available via the API as claude-sonnet-4-6.
  • Cloud Providers: Available on Amazon Bedrock, Google Cloud Vertex AI, and Microsoft Foundry.

“Sonnet 4.6 is a significant leap forward on reasoning through difficult tasks… it reached for modern tooling we didn’t ask for, all in one shot. The results genuinely surprised us.” — Yusuke Kaji, General Manager of AI at Rakuten.