# Claude Sonnet 5

Anthropic, released 2026-06-30

**Verdict: recommended.** Anthropic's most agentic Sonnet at launch delivers performance close to Opus 4.8 at 40 percent of the Opus rate. The $2/$10 per 1M token price is the standard rate: Anthropic cancelled the increase to $3/$15 that was scheduled for 1 September 2026. The newer tokenizer produces about 30 percent more tokens for the same text, so recount budgets before migrating from Sonnet 4.6. Anthropic now lists Sonnet 5 as legacy; Claude Sonnet 5.5, at the same $2/$10, is the current Sonnet, so start new work there. Last verified 2026-09-30.

## Pricing

- Input: $2 / 1M
- Output: $10 / 1M
- Context: 1M tokens; batch $1/$5; cache read $0.20

## Strengths

- Multi-step agentic coding and autonomous task completion — finishes complex workflows previous Sonnet models stalled on
- Brownfield debugging: traces failures to root causes, writes reproducing tests, and ships durable fixes unprompted
- Production AI agents at attractive cost — near-Opus 4.8 quality on agentic benchmarks at 40% of the price ($2/$10 against Opus 4.8's $5/$25)
- Knowledge work where it edges Opus 4.8 (GDPval-AA v2: 1,618 vs 1,615) — document drafting, research, professional analysis
- Self-verification: checks its own output without being explicitly prompted, reducing compounding errors in automated pipelines
- High-volume batch pipelines: the Batch API halves the rate to $1 input / $5 output per 1M, and cache reads land at $0.20 per 1M
- Maximum-capability frontier tasks where Opus 5, Fable 5 or Fable 5.1 are necessary — Sonnet 5 gets close but doesn't match the top tier
- Cybersecurity work requiring reduced guardrails — cyber safeguards are enabled by default and Anthropic recommends the Opus tier for that use case
- Workloads where the new tokenizer's ~30% token inflation matters — recount budgets before switching; same text costs more tokens than on Sonnet 4.6

## Benchmarks

- SWE-bench Verified: 85.2% (https://llm-stats.com/blog/research/claude-sonnet-5-vs-claude-opus-4-8)
- Terminal-Bench 2.1: 80.4% (https://codersera.com/blog/claude-sonnet-5-launch-guide-2026/amp/)
- SWE-bench Pro: 63.2% (https://codersera.com/blog/claude-sonnet-5-launch-guide-2026/amp/)
- Humanity's Last Exam (no tools): 43.2% (https://codersera.com/blog/claude-sonnet-5-launch-guide-2026/amp/)
- Humanity's Last Exam (with tools): 57.4% (https://codersera.com/blog/claude-sonnet-5-launch-guide-2026/amp/)
- OSWorld-Verified: 81.2% (https://codersera.com/blog/claude-sonnet-5-launch-guide-2026/amp/)
- Knowledge Work (GDPval-AA v2): 1,618 (https://www.anthropic.com/news/claude-sonnet-5)
- Cursor Production Benchmark (Max effort): 61.2% (https://kingy.ai/news/claude-sonnet-5-benchmarks-specs-pricing/)
- BrowseComp 25 (agentic search): 84.7% (https://codersera.com/blog/claude-sonnet-5-launch-guide-2026/amp/)

## Sources

- [Kingy AI — Claude Sonnet 5: Benchmarks, Specs, Pricing & Everything New](https://kingy.ai/news/claude-sonnet-5-benchmarks-specs-pricing/)
- [Anthropic pricing page](https://platform.claude.com/docs/en/about-claude/pricing)
- [TechCrunch — Anthropic launches Claude Sonnet 5](https://techcrunch.com/2026/06/30/anthropic-launches-claude-sonnet-5-as-a-cheaper-way-to-run-agents/)
- [Anthropic — Introducing Claude Sonnet 5](https://www.anthropic.com/news/claude-sonnet-5)
- [Codersera — Claude Sonnet 5: Benchmarks, Pricing & How It Compares](https://codersera.com/blog/claude-sonnet-5-launch-guide-2026/amp/)
- [Claude API docs: Models overview (Sonnet 4.6 and Sonnet 5 listed as legacy, still available; Sonnet 5.5 current)](https://platform.claude.com/docs/en/about-claude/models/overview)
- [Anthropic Platform Docs — What's new in Sonnet 5](https://platform.claude.com/docs/en/about-claude/models/whats-new-sonnet-5)
- [MarkTechPost — Claude Sonnet 5 vs Sonnet 4.6 vs Opus 4.8: Benchmarks and Cost-Performance Compared](https://www.marktechpost.com/2026/06/30/anthropic-claude-sonnet-5-vs-sonnet-4-6-vs-opus-4-8-agentic-coding-benchmarks-api-pricing-and-cost-performance-tradeoffs-compared/)

Canonical: https://neomanex.com/models/claude-sonnet-5