Claude Sonnet 4.6
Anthropic's mid-cycle November 2025 Sonnet refresh — a capability bump rather than a major-version release. Sonnet 4.6 became the default coding model behind most AI IDEs in Q4 2025, displacing both Sonnet 4 and Opus 4 in volume usage (since Opus's premium price made it overkill for most interactive coding sessions).
How are Intelligence, Speed & Cost bucketed?
- Top 1%≤ 1%
- Top 5%≤ 5%
- Top 10%≤ 10%
- Good≤ 25%
- Medium≤ 50%
- Below avg> 50%
- Top 1%≥ 345 tok/s
- Top 5%≥ 237 tok/s
- Top 10%≥ 196 tok/s
- Good≥ 146 tok/s
- Medium≥ 90 tok/s
- Slow< 90 tok/s
- Freeopen weights · self-host
- Low< $1 / M out
- Moderate$1–5 / M out
- High≥ $5 / M out
Why it matters
Sonnet 4.6 is what most production AI workflows actually run on as of early 2026 — including the IDE you're probably using to view this code. The model's specific identifier appears in this project's CLAUDE knowledge prompt as `claude-sonnet-4-6` — which is the lineage marker for the workhorse tier of the family.
Core Capabilities
Context Window
Availability
Pricing Model
Capability / Performance
Where this model sits relative to the middle 60% of models in the tree. All scores are 0–10 (higher is better).
What it feels like
- Topped SWE-bench Verified at release — Cognition reported 18% planning gain and 12% end-to-end eval gain for Devin
- Edit accuracy is the headline change — internal code-editing error rate dropped from 9% on Sonnet 4 to 0%
- Sustains 30+ hour autonomous coding focus without losing the thread
- Reasoning quality improvements are real but incremental over 4.5 — pick this for cost/speed, not for raw IQ
- Same price point as predecessor — easy upgrade if you're already on Sonnet
- Some testers find Opus 4.5 worth the premium for the hardest multi-system bugs
Best use cases
- Production agentic coding (Devin, Cursor, Cline) where reliability matters
- AI SRE / on-call automation with long task horizons
- Day-to-day software engineering at scale on real GitHub issues
- Cost-sensitive teams that need frontier-tier coding without Opus pricing
Tools to try
Not ideal for
- The very hardest reasoning tasks — Opus 4.5 still leads by ~7 points on AA Intelligence Index
- Simple chat or casual Q&A — try Haiku 4.5 instead
- Workloads where 1M-token context is required (Sonnet 4.6 ships 200K)
Model Evolution
claude-sonnet is Anthropic's language model family.