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Anthropic released Claude Haiku 5.5 on October 7, 2026, with API model ID claude-haiku-5-5. It targets high-volume, low-latency work and is the first Haiku model with adjustable effort. Availability in Tabbit depends on your account's live model picker.
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Claude Haiku 5.5 · Model overview
A compact view of reviewed task guides, public evaluations, and evidence boundaries. Client access still depends on your current account.
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Extract structured data, build a visual prototype, or start a coding task.
When migrating from Claude Haiku 4.5 to Claude Haiku 5.5, replacing the model ID is only part of the work: you must also update adaptive thinking, sampling parameters, assistant prefill, computer tools, thinking-block account binding, and append-only conversat.
Anthropic recommends starting by using effort to control Haiku 5.5's thinking depth, then adding a search date, JSON tool-call guidance, long-agent safeguards, code verification, message-injection isolation, and refusal handling based on observed behavior; exi.
Anthropic provides a Claude Haiku 5.5 low-effort customer-support ticket classification prompt with few-shot examples and XML tag constraints. It assigns each ticket a single intent and extracts the reasoning and intent separately for downstream routing.
This Reddit post shows how to point a custom Claude Code subagent, or all subagents, to Haiku 5.5. The author later found that forcing the setting globally harmed implementation tasks that needed Opus, so Haiku is better reserved for search, reading, and mecha.
Public results use different versions, tiers, and harnesses; unknown values stay unknown.
Anthropic positions Claude Haiku 5.5 as a high-throughput model for summarization, compression, database queries, classification, real-time customer support, browser operation, and coding subagents. The launch page's official comparisons show clear gains over .
Artificial Analysis's independent evaluation gives Claude Haiku 5.5 a score of 43 at max effort, placing it among the leading small models. It substantially outperforms Haiku 4.5 on knowledge work and terminal use, but uses a weighted average of about 162k out.
A Claude Code user ran a small comparison on a real, medium-sized mixed-language codebase. Haiku 5.5 Medium reached the same result as Sonnet 5.5 Medium on one cross-language agent task, while Low skipped verification and the higher tier sharply increased requ.
Anthropic
Explore Claude Haiku 5.5 specifications, reusable workflows, and evaluation evidence, then check availability in Tabbit.