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- Jun 30, 202690% CONFIDENCEfrom the source
Claude Sonnet 5 Released
- "Claude Sonnet 5 is built to be the most agentic Sonnet model yet": it plans, uses tools such as browsers and terminals and runs autonomously, with performance close to Opus 4.8 at lower prices[1][3][4]
- From launch it was the default for Free and Pro plans and available to Max, Team and Enterprise, as claude-sonnet-5 on the Claude API, with higher rate limits across Chat, Cowork, Claude Code and the Claude Platform[1]
- It launched at $2 per million input tokens and $10 per million output tokens "through August 31", with $3/$15 due to follow; on 10 August 2026 Anthropic made the introductory price permanent[1][3][4]
- It shows less misaligned behaviour than Sonnet 4.6 but more than Opus 4.8 and Claude Mythos Preview; never trained on cybersecurity, it could not build a working Firefox exploit, yet it ships with the cyber safeguards used on Opus 4.7 and 4.8[1][5]
- A drop-in upgrade for Sonnet 4.6: adaptive thinking is on by default, and manual extended thinking or non-default temperature, top_p and top_k now return an error[2]
Notable features
- Specifications: 1M-token context window, 128K max output (300K on the Batch API in beta), adaptive thinking at high default effort, text and image input with text output, and a January 2026 knowledge cutoff[2]
- Anthropic's table puts it at 63.2% on SWE-bench Pro, 80.4% on Terminal-Bench 2.1 and 81.2% on OSWorld-Verified, against Sonnet 4.6's 58.1%, 67.0% and 78.5% and Opus 4.8's 69.2%, 82.7% and 83.4%[1][3]
- On knowledge work (GDPval-AA v2) it scores 1618, just ahead of Opus 4.8's 1615 and far above Sonnet 4.6's 1395[1][3]
- A new tokenizer, like Opus 4.7's, maps the same input to roughly 1.0 to 1.35 times as many tokens[1]
- Effort levels from low to max let users trade cost for accuracy, and at high effort it matches Opus 4.8 on some tasks[1]
Benchmarks[1]
| Benchmark | Sonnet 5 | Sonnet 4.6 | Opus 4.8 (for reference) |
|---|---|---|---|
| Agentic coding (SWE-bench Pro) | 63.2% | 58.1% | 69.2% |
| Agentic coding (Terminal-Bench 2.1) | 80.4% | 67.0% | 82.7% |
| Multidisciplinary reasoning (Humanity's Last Exam), no tools | 43.2% | 34.6% | 49.8% |
| Multidisciplinary reasoning (Humanity's Last Exam), with tools | 57.4% | 46.8% | 57.9% |
| Computer use (OSWorld-Verified) | 81.2% | 78.5% | 83.4% |
| Knowledge work (GDPval-AA v2) | 1618 | 1395 | 1615 |
References 588% CONFIDENCEOverall confidence: 88%How well the pin's source and references back up its dates.Weighted average of how firmly 5 references, the source included, support the pin's start and end times; a reference counts half as much for every 180 days older than the newestShow all pins at 75% confidence or better
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- [1]90%anthropic.com/news/claude-sonnet-5anthropic.com· Posted Sep 28, 2026· Starts Jun 30, 2026 ✓· 24% of score
The post is dated "Jun 30, 2026" and says "From today, Claude[2] Sonnet 5 is available across all plans"; the docs model page lists "Released June 30, 2026" and TechCrunch's[3] 2026-06-30 report says it is the default "Starting Tuesday".
- [2]90%Claude Sonnet 5 - Claude Platform Docsplatform.claude.com· Added Sep 28, 2026· 24% of score
Anthropic's[1][5] model page: claude-sonnet-5, a drop-in upgrade for Sonnet 4.6 with adaptive thinking on by default, 1M-token context, 128K max output (300K Batch beta), $2/$10 per million tokens, text and images in, a January 2026 knowledge cutoff, "Released June 30, 2026".
- [3]88%Anthropic launches Claude Sonnet 5 as a cheaper way to run agentstechcrunch.com· Published Jun 30, 2026· Starts Jun 30, 2026· 17% of score
TechCrunch, 2026-06-30: default for Free and Pro "Starting Tuesday"; $2/$10 per million tokens through August 31, then $3/$15, cheaper than Opus 4.8, GPT-5.5 and Gemini 3.1 Pro but dearer than Gemini 3.5 Flash; 63.2% on agentic coding against Opus 4.8's 69.2% and Sonnet 4.6's 58.1%.
- [4]80%Anthropic Launches Claude Sonnet 5 With Near-Opus Performance at a Lower Pricemacrumors.com· Published Jun 30, 2026· Starts Jun 30, 2026· 17% of score
MacRumors, 2026-06-30: "Anthropic[1][5] today introduced Claude[2] Sonnet 5", its most agentic Sonnet, with performance similar to Opus 4.8, lower hallucination and sycophancy, and the launch pricing of $2/$10 before a planned rise to $3/$15.
- [5]90%System Card: Claude Sonnet 5anthropic.com· Published Jun 30, 2026· 17% of score
Anthropic's[1] system card dated "June 30, 2026", describing "the latest model in Anthropic's Sonnet family" as an upgrade to Claude[2] Sonnet 4.6, with the behavioural audit and Firefox exploit results the launch post cites.
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