SkillRank verdict
Use GPT-5.5 when your workflow benefits from OpenAI's broad tool ecosystem, multimodal product surface, and professional reasoning depth. Use Claude Opus when long-form analysis, careful writing, and agentic work review are central. Evaluate both on your own documents and code before standardizing.
Decision Matrix
Choose by workflow, risk, and fit.
The matrix turns the written comparison into a scan-friendly decision surface. It uses the same editorial comparison rows and linked model profiles.
Best first test
Cross-functional reasoning and tool workflows / Long-form analysis and careful review
Watch for
Cost on long outputs and overuse for routine tasks / Latency and ecosystem fit for product integrations
Evaluation metric
Successful task completion per dollar / Reviewer edits and groundedness
Where GPT-5.5 tends to fit
GPT-5.5 is strongest when teams want a broad frontier model inside the OpenAI ecosystem: ChatGPT workflows, API integrations, coding, research assistance, multimodal context, and tool-using product features. It is a strong default candidate when a team needs one model family across many product surfaces.
Where Claude Opus tends to fit
Claude Opus is a strong candidate for careful long-form analysis, writing-heavy workflows, repository review, policy reasoning, and tasks where users value a conservative assistant style. Teams should test it on their own high-context documents and multi-step work rather than relying only on public benchmarks.
How to evaluate them fairly
Use the same prompt, same source documents, same tool permissions, and same scoring rubric. Track answer quality, citation use, hallucination rate, latency, cost, refusal behavior, and how much human editing is needed before the output can ship.
Sources and next steps