Overview
Claude Opus 4.5 was Anthropic's flagship model before Opus 4.6 arrived. It remains an extremely strong model for coding, with particular strengths in creative problem-solving and nuanced writing. For many vibe coding tasks, the difference between 4.5 and 4.6 is minimal.
Key Specs
| Spec | Details |
|---|---|
| Model ID | claude-opus-4-5-20250929 |
| Context Window | 200,000 tokens |
| Max Output | 32,000 tokens per response |
| Input Cost | $15 per million tokens |
| Output Cost | $75 per million tokens |
| Speed | Moderate |
| Best For | Creative solutions, nuanced writing, complex coding |
Strengths for Vibe Coding
- Creative problem-solving: Often finds elegant, non-obvious solutions to coding problems
- Nuanced understanding: Excellent at understanding vague or ambiguous requirements and interpreting intent
- Clean code style: Produces well-structured, readable code with good conventions
- Strong at refactoring: Very good at restructuring existing code without breaking functionality
Opus 4.5 vs Opus 4.6
| Aspect | Opus 4.5 | Opus 4.6 |
|---|---|---|
| Raw code quality | Excellent | Slightly better |
| Instruction following | Very good | Best-in-class |
| Creative solutions | Slightly more creative | Strong |
| Agentic reliability | Good | More reliable |
| Price | Same | Same |
For most vibe coding tasks, Opus 4.5 and 4.6 perform similarly. If you have access to 4.6, use it — but 4.5 is still a top-tier option and produces excellent code.