Claude Haiku 4.5 vs Claude Sonnet 4.6

Claude Haiku 4.5

Anthropic

Claude Haiku 4.5, released by Anthropic in October 2025, is a fast, efficient large language model from the Claude 4.5 family optimized for high-throughput, low-latency workloads. It features a 200K token context window, 64K maximum output tokens, native image understanding, and extended thinking capabilities. Haiku 4.5 targets latency-sensitive applications such as real-time assistants, document classification, and lightweight agentic tasks where rapid response times are a primary requirement.

Claude Sonnet 4.6

Anthropic

Claude Sonnet 4.6 is a general-purpose language model from Anthropic, released in February 2026 as an update to the Sonnet 4 line that introduced adaptive thinking — a mode where the model automatically calibrates its reasoning depth based on task complexity rather than requiring manual configuration by the developer. The model accepts text and image inputs and integrates natively with web search and code execution tools, consolidating capabilities that previously required separate toolchain setup into a unified API surface. It became the primary workhorse model in the Claude 4 series for code assistance, agentic pipelines, and retrieval-augmented applications that benefit from built-in web access.