Key takeaways

• Claude Opus 4.1 is a proprietary, Transformer-based model by Anthropic, designed for advanced research, data analysis, and tool-assisted reasoning with extended thinking up to 64K tokens and a context length of 200,000 tokens.
• The model excels in coding (93.33% pass rate on Python tasks), reasoning, and recalling specific biological/chemical structures, and following complex directions due to strong understanding of problem constraints.
• Significant limitations include struggles with geometric problems, complex multi-step math and numerical calculations, and reasoning across multiple domains, scoring only 7.31% accuracy on the 'Humanity's Last Exam' benchmark.
• Failures often arise from misalignment with specific 'truth' implementations in coding benchmarks, numerical errors in complex scenarios, and misunderstanding subtle nuances in instructions, sometimes producing convincing but incorrect explanations.
• Despite strong performance in Python code generation, its application across diverse domains is limited by inconsistency and numerical calculation errors, requiring careful validation of outputs, especially for quantitative tasks.

Technical specifications

Context length

200k tokens

Max output

—

Architecture

Transformer

Modalities

text+image->text

Parameters

~800B

Open weights

No

Licence

Proprietary

Regions

USA

Vendor

Anthropic

Provider model key

anthropic/claude-opus-4.1