Claude Opus 5.5 vs Claude Sonnet 5.5
| Benchmark | Opus 5.5 | Sonnet 5.5 |
|---|---|---|
| AutomationBench-AA | 61.2 | 59.4 |
| GDPval-AA (work tasks) 2.1 | 1,593.3 | 1,558.1 |
| AA Analyst Agent | 56.3 · max | 57.5 · max |
| Terminal-Bench 4.0 | 52.5 | 43.9 |
| Terminal-Bench Science 0.1 | 43.3 | 34.3 |
| AA-Briefcase 1.1 · Elo | 1,620.9 | 1,634.1 |
| AA-LCR (long context) 1.1 | 84.3 | 78 |
| DeepSWE 1.1 | 72.3 · max | 70.5 · max |
| FrontierCode 1.1 | 57.1 | 44.3 |
| Harvey LAB-AA 1.1 | 4.2 · max | 2.8 · max |
| Furniture Assembly | 83.3 · max | 75 · max |
| SpireClimb | 3.3 · max | 1.3 · max |
| SpireClimb StS1 A20 Heart | 0 · max | 0 · max |
| SpireClimb StS2 A10 | 6.7 · max | 2.7 · max |
| ITBench SRE | 38.2 · max | — |
| SWE-bench Pro (v2 full) | — | 95.8 · xhigh |
| SWE-bench Pro (v2 hard) | — | 70.6 · xhigh |
| EBR Bench | 71.4 · max | — |
Specs
| Spec | Opus 5.5 | Sonnet 5.5 |
|---|---|---|
| Input, per 1M | $4 | $2 |
| Output, per 1M | $20 | $10 |
| Cost per task? | $1.34 | $0.88 |
| Speed, tok/s | 82 | 106 |
| Context | 1M | 1M |
| Weights | Closed | Closed |
| Released | Sep 2026 | Sep 2026 |
| See images | ✓ | ✓ |
| Read PDFs | ✓ | ✓ |
| Hear audio | — | — |
| Watch video | — | — |
| Call tools | ✓ | ✓ |
| Force a tool call | — | — |
| Return strict JSON | ✓ | ✓ |
| Search the web | ✓ | ✓ |
| Run code | ✓ | ✓ |
| Use a computer | ✓ | ✓ |
What breaks when you switch
No forced tool use›
Forced tool_choice any or tool returns HTTP 400; remove the forced choice.
Replace disabled thinking›
Disabled thinking returns HTTP 400; use between_tools for the lowest thinking setting.
No manual thinking budgets›
Manual thinking budgets and extra between_tools fields return HTTP 400; remove manual budgets and send between_tools without display, budget_tokens or block_binding.
Remove sampling parameters›
Non-default temperature, top_p or top_k returns HTTP 400; remove these parameters.
No assistant prefill›
A prefilled final assistant turn returns HTTP 400; remove that prefill.
Old computer tool rejected · Claude API / Google Cloud›
The computer_20251124 tool returns HTTP 400 on the Claude API and Google Cloud; use computer_toolset_20260801 there.
No forced tool use›
Forced tool_choice any or tool returns HTTP 400; remove the forced choice.
Thinking is always on›
Disabled thinking or a manual budget returns HTTP 400; omit thinking or use adaptive thinking.
Remove sampling parameters›
Non-default temperature, top_p or top_k returns HTTP 400; omit these parameters and use prompting.
No assistant prefill›
Assistant prefill returns HTTP 400; use structured outputs or system instructions, with system instructions on Bedrock.
Old computer tool rejected · Claude API / Google Cloud›
The computer_20251124 tool returns HTTP 400 on the Claude API and Google Cloud; use computer_toolset_20260801 there.
Return thinking blocks unmodified›
Edited, reordered or partially dropped thinking blocks return HTTP 400; echo assistant messages complete and unmodified with tool results.