Claude update: Haiku 5.5 adds lower prices and adjustable effort

Claude Haiku 5.5 launched on October 7 with lower API prices and adjustable effort, a setting that controls how much the model reasons. Anthropic positions it for recurring tasks such as summarization, classification, and bounded work delegated by other AI agents.

Source: Anthropic: Introducing Claude Haiku 5.5.

Claude Haiku 5.5: pricing and availability

Pricing depends on input length. These rates are per million tokens, the text units the API counts and bills:

• Prompts up to 100,000 tokens: $0.10 for input and $0.50 for output.
• Prompts over 100,000 tokens: $0.50 for input and $2.50 for output.

The model is available on Claude Platform and through AWS, Google Cloud, and Microsoft Azure. On the Claude API, use the model ID claude-haiku-5-5.

Anthropic is also cutting Claude Sonnet 5.5 cache read pricing from $0.20 to $0.10 per million tokens. This applies to input reused from the prompt cache, not to all input and output.

Source: Anthropic's Haiku 5.5 and Sonnet 5.5 pricing and availability.

Moving from Haiku 4.5: check more than the model name

Human step: Whoever maintains the integration needs to review its API requests before switching models. Anthropic's migration guide lists changes including:

• Change the model ID and recount tokens. The same text uses more tokens, affecting cost estimates and the max_tokens limit.
• If your request sets thinking to enabled with a budget_tokens limit, replace that setting with thinking: \{"type": "adaptive"\}. Thinking is adaptive by default; output_config.effort controls the level.
• Remove temperature, top_p, and top_k. Older values can produce an error instead of a response.
• Read response blocks by their type, not their position. A response can begin with a thinking block before the text arrives.
• End with a user message. The model does not accept a final assistant message for it to continue.

The guide has further requirements for computer use and replaying stored conversations. Haiku 5.5 does not support Priority Tier, so existing Haiku 4.5 capacity commitments need separate planning.

Source: Claude Haiku 5.5 migration guide.