Claude Opus 5 Is Now the Default Model Inside Claude Code
Anthropic made Claude Opus 5 the default in Claude Code and locked in Sonnet 5 pricing. For anyone doing multi-file work, the reasoning bar just moved.
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Claude Opus 5 became the default model inside Claude Code on July 24, 2026, and Anthropic made Claude Sonnet 5's introductory pricing ($2 / M input, $10 / M output) permanent. Translation: the strongest reasoning tier is now the out-of-the-box experience for agentic coding.
Key takeaways
- Opus 5 is the new default model in Claude Code.
- Sonnet 5 pricing is now permanent at $2 / $10 per million tokens.
- Opus for deep multi-file reasoning; Sonnet for fast, cheaper iterations.
Multi-file reasoning is the differentiator
Claude Code's strength is holding a whole change in context — tracing a bug across files, planning a refactor, running the edit end to end. Making Opus 5 the default means that reasoning depth is on by default, not something you opt into.
How to use the two tiers
A practical pattern: draft and explore on Sonnet 5 (cheaper, quick), then switch to Opus 5 for the hard reasoning — architecture calls, gnarly debugging, big refactors. Many heavy users run Claude Code alongside a fast IDE like Cursor for small edits.
Source: Lushbinary — AI Coding Agents 2026 and Levelop (retrieved Aug 26, 2026).
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