As of: 2026-10-08 23:45 CEST.
Researched and written by AI agents (Claude Opus 5.5 in Claude Code). Human editor: Adam Bicz.
Canonical page: https://postcutoff.com/m/claude-haiku-5-5/

# Claude Haiku 5.5

Anthropic, Claude 5 family. Status: current. Type: reasoning model. Released: 2026-10-07. Training cutoff: 2026-06.

## How to call it

| Provider | Model id | Endpoint | Docs |
|---|---|---|---|
| Anthropic API (Claude API) | `claude-haiku-5-5` | https://api.anthropic.com/v1/messages | https://platform.claude.com/docs/en/models/haiku-5-5/overview |
| AWS Bedrock | `anthropic.claude-haiku-5-5` |  | https://platform.claude.com/docs/en/build-with-claude/claude-in-amazon-bedrock |
| Google Cloud Vertex AI | `claude-haiku-5-5` |  | https://platform.claude.com/docs/en/build-with-claude/claude-on-vertex-ai |
| Microsoft Foundry (Azure) | `claude-haiku-5-5` |  | https://platform.claude.com/docs/en/build-with-claude/claude-in-microsoft-foundry |
| Claude Platform on AWS | `claude-haiku-5-5` |  | https://platform.claude.com/docs/en/build-with-claude/claude-platform-on-aws |
| Web app |  |  | https://claude.ai |

## Pricing

- Input: $0.10 per 1M tokens
- Output: $0.50 per 1M tokens
- Cache read: $0.01 per 1M tokens
- Unit as published: per 1M tokens (USD) for prompts up to 100K tokens; above 100K: $0.50 input / $2.50 output / $0.05 cache read; 5-min cache write $0.125 ($0.625 >100K); Batch API 50% off
- Source: https://platform.claude.com/docs/en/models/haiku-5-5/overview
- Last checked: 2026-10-08

## Specs

- Input: text, image
- Output: text
- Context window: 1,000,000 tokens
- Max output: 128,000 tokens
- Open weights: no
- Licence: proprietary

## What it has not seen

- Published training cutoff: 2026-06 (June 2026).
- AI events after it on Post-Cutoff: 711 (174 major, 36 historic), as of 2026-10-08.
- Already missing at launch: 671.
- Briefings of the news since June 2026: https://postcutoff.com/briefings/cutoff-2026-06-s.md (short), https://postcutoff.com/briefings/cutoff-2026-06-m.md (medium), https://postcutoff.com/briefings/cutoff-2026-06.md (full).
- Its card, with five things it has never heard of: https://postcutoff.com/you/claude-haiku-5-5/

## What stands out

- First Haiku with effort control (first): Adaptive thinking steered by the effort parameter (low, medium, high, xhigh, max; default medium); thinking: {type: disabled} works at high effort or below and returns 400 at xhigh/max; per-message effort changes in beta. Source: https://platform.claude.com/docs/en/build-with-claude/effort
- Two-tier long-context pricing: $0.10/$0.50 per MTok up to 100K prompt tokens, five times that above 100K; 90% below Haiku 4.5 and equal to GPT-6 Luna at the low tier. Source: https://platform.claude.com/docs/en/models/haiku-5-5/overview
- Frontier-level prompt-injection robustness in a small model: System card: Gray Swan IPI attack success at k=15 of 7.1% (Haiku 4.5: 83.2%); 0.08% against the Shade adaptive coding attacker (Haiku 4.5: 58.40%). Source: https://www.anthropic.com/document/claude-haiku-5-5-system-card
- Strong computer use for its price: Anthropic reports OSWorld 2.1 at 72.4%, versus 48.9% for GPT-6 Luna. Source: https://www.anthropic.com/claude-haiku-5-5

## Notes

Anthropic's fastest and cheapest current model, for classification, extraction, routing and subagents. Uses the Claude 4.7+ tokenizer (~30% more tokens than Haiku 4.5 for the same text). Migrating from Haiku 4.5: manual extended thinking (budget_tokens) returns 400; responses can begin with thinking blocks. Non-default temperature/top_p/top_k return 400. Batch API supports 300K output with the output-300k-2026-03-24 beta header. Retirement not sooner than 2027-10-07.

Cheapest Claude 5.5 model; the long-context surcharge starts at 100K prompt tokens.

```bash
curl https://api.anthropic.com/v1/messages \
 -H "x-api-key: $ANTHROPIC_API_KEY" -H "anthropic-version: 2023-06-01" -H "content-type: application/json" \
 -d '{"model":"claude-haiku-5-5","max_tokens":4000,"output_config":{"effort":"low"},"messages":[{"role":"user","content":"Classify: ..."}]}'
```

Sources:
- Model page: https://platform.claude.com/docs/en/models/haiku-5-5/overview
- Announcement: https://www.anthropic.com/claude-haiku-5-5
- System card: https://www.anthropic.com/document/claude-haiku-5-5-system-card
- Models overview: https://platform.claude.com/docs/en/about-claude/models/overview

Model page: https://postcutoff.com/m/claude-haiku-5-5/