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Anthropic releases Claude Haiku 5.5 with major breaking changes for developers

By PulseAugur Editorial · [1 sources] ·

Anthropic has released Claude Haiku 5.5, introducing adaptive thinking and a 1M-token context window, but with significant changes for developers migrating from Haiku 4.5. Key breaking changes include the deprecation of `budget_tokens` and `temperature` parameters, requiring developers to use `output_config.effort` and prompt-based steering instead. Additionally, the model now enforces stricter rules on conversation history and tool usage, with specific tool names varying across platforms like Amazon Bedrock and Google Cloud. AI

IMPACT Requires developers to update their integrations due to significant API changes and parameter deprecations.

RANK_REASON Frontier-lab model release with system card. [lever_c_demoted from frontier_release: ic=1 ai=1.0]

Read on dev.to — Anthropic tag →

AI-generated summary · Google Gemini · from 1 sources. How we write summaries →

Anthropic releases Claude Haiku 5.5 with major breaking changes for developers

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Frontier-lab model release with system card. [lever_c_demoted from frontier_release: ic=1 ai=1.0]
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model release, product
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COVERAGE [1]

  1. dev.to — Anthropic tag TIER_1 English(EN) · Pesimmoq ·

    Migrating from Haiku 4.5 to Claude Haiku 5.5: 6 breaking changes and when the price goes up 5x

    <p>Claude Haiku 5.5 (<code>claude-haiku-5-5</code>) was released on October 7, 2026. It is the first Haiku with adaptive thinking and effort, has a 1M-token context window and 128K output, and its API shape now matches Opus 5.5 / Sonnet 5.5. Pricing is $0.10 / $0.50, one tenth of…

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