# Claude Sonnet 4.6 ![Organization](https://img.shields.io/badge/Org-Anthropic-d97757) ![Type](https://img.shields.io/badge/Type-Hybrid%20reasoning-555) ![Context](https://img.shields.io/badge/Context-1M%20tokens-1f6feb) ![Pricing](https://img.shields.io/badge/Price-%243%20%2F%20%2415%20per%201M-2da44e) ![License](https://img.shields.io/badge/License-Proprietary-d29922) ![Modality](https://img.shields.io/badge/Modality-Text%20%2B%20Vision-8957e5) ![Released](https://img.shields.io/badge/Released-Feb%202026-555) > **Quick answer:** Claude Sonnet 4.6 is Anthropic's cost-efficient frontier model, released 17 February 2026. It pushes near Opus-level intelligence at Sonnet pricing ($3/$15 per million tokens), adds a 1M-token context window (beta), and excels at coding, computer use, and agent planning. Anthropic reports 80.2% on SWE-bench Verified. It is a closed, API-only model (`claude-sonnet-4-6`). ## At a Glance **Where Claude Sonnet 4.6 leads** - Near-flagship intelligence at a third of Opus's price — $3 / $15 per 1M tokens. - Strong agentic coding (80.2% on SWE-bench Verified) and computer use (94% on a partner insurance benchmark; large OSWorld-Verified gains). - A 1M-token context window (beta) that it reasons across, not just stores. **Where it lags** - Opus 4.6 remains stronger for the deepest reasoning — large refactors and multi-agent coordination. - Closed and API-only with no open weights to self-host, and the 1M window is still in beta. **Best for:** teams that want most of the frontier's capability at mid-tier cost for broad, high-volume agent work. ## What Claude Sonnet 4.6 Is Claude Sonnet 4.6 is the mid-tier of Anthropic's Claude family, but the gap to the flagship has narrowed sharply. Anthropic frames it as approaching Opus-level intelligence at a price point — $3/$15 per million input/output tokens — that makes it practical for far more tasks. In Anthropic's early testing, developers preferred Sonnet 4.6 to the previous Sonnet 4.5 roughly 70% of the time, and even preferred it to the November 2025 flagship Opus 4.5 about 59% of the time, citing less overengineering, fewer false claims of success, and stronger instruction following. Like Opus 4.6, it is a hybrid reasoning model supporting both adaptive and extended thinking, with a 1M-token context window in beta — enough to hold an entire codebase, a long contract, or dozens of papers in one request. Anthropic stresses that Sonnet 4.6 reasons effectively *across* that context, not just stores it, which translates into better long-horizon planning. The release also leans hard into computer use, with major gains on the OSWorld-Verified benchmark and partner reports of human-level performance on multi-step web and spreadsheet tasks. For Benchgen, Sonnet 4.6 is an API-benchmarked model with no open weights. Its appeal is the cost-to-capability ratio: if a much cheaper model completes domain agent tasks nearly as reliably as a flagship, that is exactly the kind of finding a verified, repeated-trial evaluation surfaces and an aggregator's single-number leaderboard hides. The question Benchgen answers is how reliably that value holds across repeated attempts on a specific task. ## Specifications | Field | Value | |---|---| | Organization | Anthropic | | Model type | Hybrid reasoning model (adaptive + extended thinking; effort controls) | | API identifier | `claude-sonnet-4-6` | | Access | Closed, API only (Claude apps, Anthropic API, AWS, Google Cloud, Microsoft Foundry) | | Context window | 1M tokens (beta) | | License | Proprietary | | Release date | 17 February 2026 | | Modality | Multimodal (text and vision) | ## Pricing | | Input (per 1M tokens) | Output (per 1M tokens) | |---|---|---| | Anthropic | $3.00 | $15.00 | Pricing is unchanged from Sonnet 4.5. Source: [Anthropic — Introducing Claude Sonnet 4.6](https://www.anthropic.com/news/claude-sonnet-4-6). ## Context Window Claude Sonnet 4.6 has a **1M-token context window** (in beta) — roughly **1,500 pages** of text in a single request. That is enough to hold an entire codebase, a long contract, or dozens of papers at once, and Anthropic stresses that Sonnet 4.6 reasons effectively *across* that context rather than merely storing it, which translates into better long-horizon planning. ## Public Benchmark Scores | Benchmark | Score | Source | Date | |---|---|---|---| | [SWE-bench Verified](/benchmarks/swe-bench-verified) (prompt-modified, 10-trial avg) | 80.2% | [Anthropic — Introducing Claude Sonnet 4.6](https://www.anthropic.com/news/claude-sonnet-4-6) | 2026-02 | | ARC-AGI-2 (high effort) | 60.4% | [Anthropic — Introducing Claude Sonnet 4.6](https://www.anthropic.com/news/claude-sonnet-4-6) | 2026-02 | | Pace insurance benchmark (computer use, partner) | 94% | [Anthropic — Introducing Claude Sonnet 4.6](https://www.anthropic.com/news/claude-sonnet-4-6) | 2026-02 | | Box heavy-reasoning Q&A (partner, vs Sonnet 4.5) | +15 pts | [Anthropic — Introducing Claude Sonnet 4.6](https://www.anthropic.com/news/claude-sonnet-4-6) | 2026-02 | *Scores above are reported by Anthropic (some via named partners) and shown for context. They are not Benchgen measurements. Figures depend on harness, effort level, and tool settings — see the source for methodology.* ## Claude Sonnet 4.6 vs Alternatives | Model | Context | SWE-bench Verified | Price (in/out per 1M) | |---|---|---|---| | **Claude Sonnet 4.6** | 1M (beta) | 80.2% | $3 / $15 | | [Claude Opus 4.6](/models/anthropic/claude-opus-4-6) | 1M (beta) | 81.42% | $5 / $25 | | [GPT-5](/models/openai/gpt-5) | 400K | 74.9% | $1.25 / $10 | | [Gemini 3 Pro](/models/google/gemini-3-pro) | 1M | 76.2% | $2 / $12 | The most telling comparison is internal: Sonnet 4.6 trails Anthropic's own Opus 4.6 by roughly a point on SWE-bench Verified while costing 40% less, and Anthropic concedes Opus stays stronger for the deepest reasoning. Against GPT-5 it offers a far larger context window at a higher token price. For agent builders the decision is usually budget-driven — how much capability per dollar a workflow actually needs. *(Rival scores attributed to [Anthropic](https://www.anthropic.com/news/claude-opus-4-6), [OpenAI](https://openai.com/index/introducing-gpt-5/), and [Google](https://blog.google/products/gemini/gemini-3/); not Benchgen measurements.)* ## How Claude Sonnet 4.6 Performs on Real Agent Tasks Sonnet 4.6's public story is unusually agent- and work-focused for a mid-tier model: strong computer-use results on OSWorld-Verified, an inventive long-horizon strategy on the Vending-Bench Arena business-simulation eval, and partner benchmarks in insurance, financial services, and enterprise document Q&A. Anthropic explicitly markets it for branched, multi-step workflows like contract routing and CRM coordination — the connective tissue of real agentic systems. What none of those public numbers establish is reproducible reliability on a *specific* domain task under a single rubric. A leaderboard number measures general capability; what agent builders actually need is reliable, repeated completion of the task in front of them — including how often the model fails, and why. Because Sonnet 4.6's headline selling point is value — near-flagship behaviour at a third of the cost — that reliability-under-repetition view is exactly what Benchgen is built to surface. ## Use Claude Sonnet 4.6 via API ```python from anthropic import Anthropic client = Anthropic(api_key="YOUR_API_KEY") message = client.messages.create( model="claude-sonnet-4-6", max_tokens=1024, messages=[{"role": "user", "content": "Summarize this contract clause..."}], ) print(message.content[0].text) ``` ## Related Models & Benchmarks - Compare: [Claude Opus 4.6](/models/anthropic/claude-opus-4-6) · [GPT-5](/models/openai/gpt-5) · [Gemini 3 Pro](/models/google/gemini-3-pro) · [Grok 4](/models/xai/grok-4) - Benchmarks: [SWE-bench Verified](/benchmarks/swe-bench-verified) ## Frequently Asked Questions

What is Claude Sonnet 4.6?

It is Anthropic's cost-efficient frontier model, released 17 February 2026, offering near Opus-level intelligence at Sonnet pricing, with a 1M-token context window and strong coding and computer-use skills.

What is Claude Sonnet 4.6's context window?

Up to 1 million tokens, available in beta.

How much does Claude Sonnet 4.6 cost?

$3 per million input tokens and $15 per million output tokens — the same as Sonnet 4.5.

Is Claude Sonnet 4.6 open source?

No. It is a proprietary, closed model available only through Anthropic's API and apps; there are no downloadable weights.

--- *Specs and scores sourced from [Anthropic's Claude Sonnet 4.6 announcement](https://www.anthropic.com/news/claude-sonnet-4-6). Third-party benchmark scores attributed inline to Anthropic. Benchgen scores, where shown, are produced on Benchgen infrastructure. Last updated 2026-06-17.*

Claude Sonnet 4.6 — Files