Claude Haiku 5.5

claude-haiku-5-5. Anthropic's models overview lists that same string as the Claude API id, the Claude API alias, the Google Cloud id, the Microsoft Foundry id, and the Claude Platform on AWS id. Amazon Bedrock is anthropic.claude-haiku-5-5.

Released 7 October 2026. Retirement is not sooner than 7 October 2027. Reliable knowledge cutoff and training-data cutoff are both June 2026. Comparative latency in the current lineup is Fastest. Default effort is medium.

Two tiers, not one rate. Prompts up to 100,000 tokens: $0.10 input and $0.50 output per million tokens. Prompts over 100,000 tokens: $0.50 input and $2.50 output. That is a 5× jump on both sides of the rate card.

Against Haiku 4.5's $1 / $5 list, the short-prompt tier is one tenth of the old input rate and one tenth of the old output rate. Anthropic's announcement separately says Haiku 5.5 costs around 75% less to run on average, and that prompts up to 100K tokens were about 90% of requests to the previous Haiku. The 75% figure is a vendor average, not the short-tier rate cut.

Cache reads are $0.01 under 100K and $0.05 over 100K. Five-minute cache writes are $0.125 / $0.625. One-hour cache writes are $0.20 / $1. Batch API is 50% off input and output. The same announcement cuts Sonnet 5.5 cache reads from $0.20 to $0.10 per million tokens.

1,000,000 input tokens and 128,000 output tokens. Haiku 4.5 was 200,000 and 64,000. On the Message Batches API, Haiku 5.5 can go to 300,000 output tokens with the output-300k-2026-03-24 beta header.

The window got larger, but the tokenizer changed. Haiku 5.5 uses the tokenizer introduced with Claude 4.7. Anthropic says the same text counts as approximately 30% more tokens than on Haiku 4.5. A prompt that used to sit under a budget can cross the 100K price cliff after the recount. Thinking tokens also count toward max_tokens, so a small cap can stop after a thinking block and before any text.

Adaptive thinking is on by default. Anthropic's what's-new page says you can still turn thinking off with thinking: {"type": "disabled"} at high effort or below. The control they want you to use is effort, not a thinking-off switch. Default effort is medium.

Breaking changes on the same page: manual extended thinking (budget_tokens) returns an error. Non-default temperature, top_p, and top_k return an error. Assistant-message prefill returns an error — end messages with a user turn. On the Claude API and Google Cloud, replace computer_20250124 with computer_toolset_20260801.

Responses can start with a thinking block. Read content by type, not by position. Summarized thinking text is omitted unless you set thinking.display to summarized. Thinking blocks work only in the account that produced them, or an account linked to it. Safety classifiers can return stop_reason: "refusal", and server-side fallback is not available.

Anthropic does not position it that way. The models overview calls Haiku 5.5 the model for high-volume, latency-sensitive work: classification, extraction, routing, and subagent tasks. Opus 5.5 is the starting point for most workloads. The announcement says Sonnet 5.5 and Opus 5.5 remain the better choice for complex agentic coding such as Terminal-Bench 4.0, and that Haiku 5.5 fits compaction, summarization, and subagent work.

On Anthropic's announcement table, Terminal-Bench 4.0 is 39.2% for Haiku 5.5, 0.0% for Haiku 4.5, 16.4% for GPT-6 Luna, and 70.6% for Sonnet 5.5. FrontierCode 1.1 Main is 46.4% versus Luna 42.4% and Sonnet 5.5 52.1% at Xhigh. Those are vendor numbers.

Reddit, last two days, asked the same question directly: r/ClaudeCode — “Is Haiku 5.5 good enough to be your main coding agent, not just the cheap one?” (score 62, 39 comments). OP ran a small controlled test on a mixed Rust codebase. Commenters split: one said it is the classification model, another said they use it for board updates and branch cleanup, another dismissed it for anything past a simple HTML game. Those are user reports, not a lab result.

The short-prompt rate card is $0.10 / $0.50 against Opus 5.5 at $4 / $20. Input is 40× lower on that tier. Output is 40× lower too. That ratio dies once the prompt crosses 100K tokens: Haiku jumps to $0.50 / $2.50, which is 8× below Opus on input and output, not 40×.

A user report, not a vendor doc: r/ClaudeCode — “Haiku 5.5 is 40× cheaper than Opus 5.5. Your Explore subagent is probably still running on Opus” (score 522, 106 comments). OP says Claude Code's built-in Explore subagent uses the main model, so an Opus 5.5 session still pays Opus for Explore. Commenters argued about routing every subagent to Haiku versus keeping Sonnet on implementers. This page does not confirm the Claude Code default. The price ratio above is the only part that comes from Anthropic's card.

The question is from a user thread, and the thread itself does not agree on the number. r/ClaudeAI — “Claude Haiku 5.5 cost 12× more than GPT-6 Luna for the same voxel pagoda” (score 1086, 130 comments). OP posted a voxel-pagoda run and blamed token use plus the 5× price jump after 100K context. The auto-summary after 100 comments called the bench sus. The top comment (score 405) said the poster often does not share prompts and may be steering the models. Another comment (score 100) pointed at the same 5× cliff if context lands around 400–500K. Another (score 41) asked what the under-100K price is for, if small edits already blow past it.

What is vendor fact: over 100K tokens, Haiku 5.5 input and output are both 5× the short-prompt rate. What is not vendor fact: the $24.96 versus $1.96 comparison in that post. Do not treat it as a benchmark.

Subscription limits are not on the API rate card. The question showed up here: r/ClaudeCode — “$20 sub usable with Haiku 5.5 for personal projects?” (score 1, 19 comments). OP hoped Haiku 5.5 would keep a $20 plan under the cap for small personal apps. Replies were user reports: several people said a $20 plan already covers light Opus 5.5 or Sonnet 5.5 use, and that Haiku is the wrong default for everything. One reply said their personal project still needs Fable with Opus 5.5 subagents. No one in the sampled comments published a measured weekly cap for Haiku 5.5.

Separate vendor note from the announcement: Max 5× is slated for $100/month of Claude Platform API credit, Max 20× for $200, and Team for up to $500 pooled. That credit is for API experiments, not a statement about the $20 chat plan.

Anthropic's product page says Haiku 5.5 is available in Claude Code, and that Free, Pro, Max, Team, and Enterprise users can select it on Claude.ai. It does not document a desktop-app update bug.

A user report from the last two days: r/ClaudeCode — “I can't update the app to use Haiku 5.5” (score 1, 3 comments). OP said the in-app update button does nothing, a fresh download shows Haiku 5.5, and a restart hides it again. Sonnet 5.5's earlier app update had stuck. The sampled comments did not include a fix. Treat that as an install report, not as an API outage.

Anthropic's announcement: available now on all of those platforms, including Amazon Web Services, Google Cloud, and Microsoft Azure. Developers start with claude-haiku-5-5. The product page also lists Claude Code, and Claude.ai for Free, Pro, Max, Team, and Enterprise.

Browser-use tool is new, on the Claude API and Google Cloud. Input is text and images. Output is text. A public llmrelay listing is still pending. This page does not quote a relay price and does not sell the id.

Vendor benches from the 7 October announcement, not independent scores. GDPval-AA v2.1: Haiku 5.5 1620, Haiku 4.5 735, GPT-6 Luna 1437, Sonnet 5.5 1840. OSWorld 2.1 offline subset: 72.4%, 15.7%, 48.9%, 83.9%. Humanity's Last Exam with tools: 57.4%, 18.7%, not listed for Luna, 64.5%. Chartography with no tools: 46.4%, 6.4%, 29.1%, 61.6%.