Claude Opus 5.5 vs GPT-5.6 Sol
Terminal-Bench 4.0 Terminal-Bench 4.0 · source setting 2: Agents use a terminal to complete executable coding, system administration and research tasks in the 4.0 suite
Opus 5.552.5
GPT-5.6 Sol14.6
DeepSWE 1.1 DeepSWE 1.1: Agents change repository code to resolve software engineering tasks under the stated DeepSWE edition
Opus 5.5 · max72.3
GPT-5.6 Sol61.1
SciCode SciCode: Writing code for real scientific computing problems (physics, biology, math)
Opus 5.559.3
GPT-5.6 Sol57.4
Terminal-Bench Science 0.1 Terminal-Bench Science 0.1: Agents complete expert-authored research workflows across five scientific domains in a terminal
Opus 5.543.3
GPT-5.6 Sol · max22.4
MirrorCode MirrorCode: Agents reimplement software projects by observing their behavior
Opus 5.5 · max77.4
GPT-5.6 Sol · high20
FrontierCode 1.1 FrontierCode 1.1: Agents implement changes in real repositories, graded against maintainer-defined requirements
Opus 5.557.1
GPT-5.6 Sol—
WebDev Arena WebDev Arena: Human pairwise preferences in the stated webdev vote pool
Opus 5.5 · max1,807
GPT-5.6 Sol—
SWE-bench Pro (v2 full) SWE-bench Pro (v2 full): Agents resolve repository issues under the network-locked v2 protocol; full and 51-task Hard results are separate
Opus 5.5—
GPT-5.6 Sol · xhigh95.5
SWE-bench Pro (v2 hard) SWE-bench Pro (v2 hard): Agents resolve repository issues under the network-locked v2 protocol; full and 51-task Hard results are separate
Opus 5.5—
GPT-5.6 Sol · xhigh82.4
Terminal-Bench Hard (version unstated) Terminal-Bench Hard (version unstated): Agents solve difficult software, system-administration and data-processing tasks in a terminal
Opus 5.5—
GPT-5.6 Sol62.9
MultiLangBenchlab MultiLangBench: Models build a SQLite-compatible database engine in 20 programming languages
Opus 5.5—
GPT-5.6 Sol26.8
| Benchmark | Opus 5.5 | GPT-5.6 Sol |
|---|---|---|
| Terminal-Bench 4.0 | 52.5 | 14.6 |
| DeepSWE 1.1 | 72.3 · max | 61.1 |
| SciCode | 59.3 | 57.4 |
| Terminal-Bench Science 0.1 | 43.3 | 22.4 · max |
| MirrorCode | 77.4 · max | 20 · high |
| FrontierCode 1.1 | 57.1 | — |
| WebDev Arena | 1,807 · max | — |
| SWE-bench Pro (v2 full) | — | 95.5 · xhigh |
| SWE-bench Pro (v2 hard) | — | 82.4 · xhigh |
| Terminal-Bench Hard (version unstated) | — | 62.9 |
| MultiLangBenchlab | — | 26.8 |
Specs
| Spec | Opus 5.5 | GPT-5.6 Sol |
|---|---|---|
| Input, per 1M | $4 | $4 |
| Output, per 1M | $20 | $20 |
| Cost per task? | $1.34 | $0.50 |
| Speed, tok/s | 81 | 85 |
| Context | 1M | 1.05M |
| Weights | Closed | Closed |
| Released | Sep 2026 | Jul 2026 |
| See images | ✓ | ✓ |
| Read PDFs | ✓ | Partial |
| Hear audio | — | — |
| Watch video | — | — |
| Call tools | ✓ | ✓ |
| Force a tool call | — | Partial |
| Return strict JSON | ✓ | ✓ |
| Search the web | ✓ | ? |
| Run code | ✓ | ? |
| Use a computer | ✓ | ? |
What breaks when you switch
Opus 5.5 → GPT-5.6 Sol
Nothing known.
GPT-5.6 Sol → Opus 5.5
Context: 1.05M → 1M
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.