- Provider
- Anthropic
- Family
- Claude 4.x
- Context window
- 200K tokens
- Modality
- text, vision, tool use
- Last updated
- 2026-04-19
At a glance
Claude Opus 4.6 is the previous-generation Opus, still used via Claude Code's fast mode for Opus-class reasoning at lower latency. It is not a downgraded model — it is a different tradeoff.
Strengths
- Opus-class reasoning quality
- Faster output than Opus 4.7 — better for interactive coding
- Powers Claude Code's /fast toggle
Weaknesses
- Superseded by 4.7 for the absolute hardest reasoning
- Not available everywhere Opus 4.7 is — check provider routing
Best for
- Claude Code fast mode
- Interactive coding sessions
- Tasks that need Opus-class quality at lower latency
When fast-mode Opus beats 4.7
For interactive coding — where you are iterating on a diff and want answers in seconds, not tens of seconds — Opus 4.6 in fast mode is often the better choice. The quality floor is still Opus-class, the latency is much better, and you get through more turns per minute.
Frequently asked questions
What is Claude Opus 4.6 fast mode?
Claude Opus 4.6 fast mode is Anthropic's Opus variant tuned for faster output. It powers Claude Code's /fast toggle and is the right pick for interactive coding where latency matters as much as quality.