Anthropic ClaudevSonnet 4.6 / Haiku 4.5

5 February 2026

Claude Sonnet 4.6 and Haiku 4.5 — Faster, Cheaper, More Capable

Anthropic's mid-cycle 2026 releases refine the Claude 4 family: Sonnet 4.6 sets a new benchmark for coding and instruction following at mid-tier pricing, while Haiku 4.5 becomes the fastest small model available with significantly improved reasoning over Haiku 4.

• 1Claude Sonnet 4.6 — 15% improvement on SWE-bench coding tasks over Sonnet 4; better at multi-step tool use and long-form structured output
• 2Claude Haiku 4.5 — 50ms median time-to-first-token; closes the reasoning gap with Sonnet 3.5 while costing 8× less
• 3Computer use 2.0 — improved UI element detection, supports scrolling, drag-and-drop, and multi-tab workflows
• 4Files API GA — upload PDFs, CSVs, and images once and reference them across multiple API calls without re-uploading
• 5Message Batching API — submit up to 10,000 requests in a single batch for 50% cost reduction on bulk workloads
• 6Model Context Protocol (MCP) certified connectors — Anthropic-signed MCP servers for GitHub, Jira, Linear, and Notion
• 7Token efficiency: Sonnet 4.6 produces 20% fewer output tokens on average for equivalent tasks through improved response calibration