Claude Sonnet 4.6
v4.6Anthropic
Anthropic's previous-generation Sonnet workhorse, superseded by Claude Sonnet 5 (2026-06-30) as the best speed/intelligence balance at the same $3/$15 price. Still fully supported (Active, tentative retirement not sooner than 2027-02-17), with a 1M token context window, 128K max output, adaptive thinking, the effort parameter including 'max', and strong computer-use accuracy.
Trust Vector Analysis
Dimension Breakdown
🚀Performance & Reliability+
Former value workhorse of the Claude lineup: near-Opus intelligence at Sonnet latency and price, with a 1M context window, adaptive thinking, and the full effort range including 'max'. Superseded by Claude Sonnet 5 (2026-06-30, same $3/$15 with intro $2/$10 through 2026-08-31) — prefer Sonnet 5 for new builds.
Review of official model documentation and positioning for software engineering workloads
Review of documented thinking capabilities and reasoning benchmark positioning
Comprehensive knowledge and multimodal capability review against official documentation
Internal testing of output stability across effort levels and adaptive thinking
Median latency for API requests with standard prompt sizes
95th percentile response time across diverse workloads
Official specification from provider
Historical uptime data from official status page
🛡️Security+
Strong safety posture. Like Opus 4.6, last-assistant-turn prefills return a 400 — structured outputs (output_config.format) are the supported replacement.
Testing against OWASP LLM01 prompt injection attacks
Testing against adversarial prompt datasets
Analysis of privacy policies and data handling practices
Comprehensive safety testing across harmful content categories
Review of API security features and best practices
🔒Privacy & Compliance+
Same enterprise-grade privacy posture as the Opus tier: ephemeral data handling, strong certifications, HIPAA eligible.
Review of enterprise documentation and privacy policies
Analysis of privacy policy and data usage terms
Review of terms of service and data retention policies
Review of data protection capabilities and customer responsibilities
Verification of compliance certifications and audit reports
Review of data handling practices
👁️Trust & Transparency+
Transparent compute controls (adaptive thinking + effort) and thorough migration documentation. Follows instructions closely, reducing prompt-engineering opacity.
Evaluation of reasoning transparency and explanation capabilities
Testing on factual QA datasets and real-world usage
Evaluation on bias benchmarks and diverse demographic testing
Qualitative assessment of confidence expression in outputs
Review of documentation completeness and clarity
Review of public disclosures about training data
Analysis of built-in safety mechanisms
⚙️Operational Excellence+
Production-ready with multi-cloud availability. Migration from Sonnet 4.5 requires setting effort explicitly (4.6 defaults to high) and removing assistant prefills.
Review of API design, consistency, and feature completeness
Review of SDK quality, documentation, and maintenance
Review of versioning policy and historical practices
Review of available monitoring tools and metrics
Assessment of documentation, community, and support responsiveness
Analysis of third-party integrations and tools
Review of licensing terms and restrictions
- +Strong speed/intelligence balance at $3/$15 per 1M tokens (Sonnet 5 now leads the tier)
- +1M token context window with 128K max output (300K on the Batch API extended-output beta)
- +Adaptive thinking supported — no manual thinking budgets to tune
- +Effort parameter including 'max' (not available on Sonnet 4.5 or Haiku)
- +Strong computer-use accuracy for agentic automation
- +HIPAA eligible with ephemeral data handling
- +Multi-cloud availability (AWS, GCP, Azure)
- !Lower ceiling than Opus tier on the hardest reasoning and long-horizon agentic tasks
- !Removed assistant prefills — code relying on prefills returns 400
- !Effort defaults to high — Sonnet 4.5 migrations see higher latency/cost unless effort is set explicitly
- !Superseded by Claude Sonnet 5 (2026-06-30): 62.3% vs 72.7% SWE-bench Verified at the same standard price
- !No native audio capabilities
Use Case Ratings
code generation
Excellent agentic coding at a fraction of Opus cost. Pair effort 'medium' with adaptive thinking for the best cost/quality balance.
customer support
The sweet spot for support: fast, empathetic, and cost-effective at scale. Use effort 'low' with thinking disabled for high-volume tiers.
content creation
Strong long-form and marketing content with fast turnaround. Opus tier still leads on the most nuanced pieces.
data analysis
Solid analytical capabilities with 1M context for large datasets at workhorse pricing.
research assistant
1M context handles large corpora; adaptive thinking deepens analysis when needed. Opus preferred for the hardest synthesis tasks.
legal compliance
Strong privacy posture, HIPAA eligible, 1M context for contract repositories. Escalate the highest-stakes reviews to Opus.
healthcare
HIPAA eligible with strong privacy controls. Well-suited to clinical documentation at production volume.
financial analysis
Good quantitative reasoning with predictable cost. Use effort 'high' for complex modeling; Opus for the hardest problems.
education
Fast, patient explanations at a price point that scales to large student populations.
creative writing
Capable creative writing with good narrative flow; Opus tier produces more distinctive prose.