Claude Haiku 4.5 vs Claude Haiku 5.5
| Benchmark | Haiku 4.5 | Haiku 5.5 |
|---|---|---|
| Humanity's Last Exam | 4.2 | 33.8 |
| Terminal-Bench 4.0 | 0 | 15.2 |
| AutomationBench-AA | 3.2 | 28.6 |
| MMMU-Pro (vision) | 55.1 | — |
Specs
| Spec | Haiku 4.5 | Haiku 5.5 |
|---|---|---|
| Input, per 1M | $1 | $0.10 |
| Output, per 1M | $5 | $0.50 |
| Cost per task? | — | $0.047 |
| Speed, tok/s | 86 | 174 |
| Context | 200K | 1M |
| Weights | Closed | Closed |
| Released | Oct 2025 | Oct 2026 |
| See images | ✓ | ✓ |
| Read PDFs | Partial | Partial |
| Hear audio | — | — |
| Watch video | — | — |
| Call tools | ✓ | ✓ |
| Force a tool call | Partial | Partial |
| Return strict JSON | ✓ | ✓ |
| Search the web | ? | ✓ |
| Run code | ? | ✓ |
| Use a computer | ? | ? |
What breaks when you switch
Haiku 4.5 → Haiku 5.5
Remove sampling parameters›
Unsupported sampling values, any top_k or combined temperature and top_p return HTTP 400; omit all three and use prompting.
Replace manual thinking budgets›
Manual thinking with budget_tokens returns HTTP 400; replace the old thinking configuration.
No assistant prefill›
A final assistant prefill returns HTTP 400 even with thinking off; end messages with a user turn.
Replace old computer tool · Claude API / Google Cloud›
computer_20250124 returns HTTP 400 on the Claude API and Google Cloud; use computer_toolset_20260801 there.
Keep conversations append-only›
Replaying thinking after earlier history changes returns HTTP 400, with older accounts checked only when the binding field is set; keep history append-only.
Bedrock needs another computer version · Bedrock›
Bedrock does not accept computer_20250124; use computer_20251124 with the computer-use-2025-11-24 beta header.
Haiku 5.5 → Haiku 4.5