Anthropic Launches Claude Sonnet 5 With Agentic Focus, Tiered Pricing
The new mid-tier model closes the gap with Anthropic's Opus-class models on coding and tool use, launching at introductory rates before a price increase in September.
Anthropic on June 30 released Claude Sonnet 5, a mid-tier model the company says is its most capable Sonnet-class model for agentic tasks — work that involves autonomous planning, tool use, and multi-step execution without constant human input. [1]
The model is positioned between Anthropic’s previous Sonnet-class releases and its higher-end Opus models. According to Anthropic, Sonnet 5’s performance is close to that of Opus 4.8 on agentic benchmarks, while carrying a lower price tag. [1]
On two agentic evaluations — BrowseComp, which tests web search and research, and OSWorld-Verified, which tests computer use — Sonnet 5 is described as a strict improvement over its predecessor, Sonnet 4.6, though Opus 4.8 still leads at higher accuracy levels. [1]
Anthropic says early access partners reported that the model completes complex tasks where previous Sonnet models would stop short, and checks its own output without being explicitly prompted to do so. [1]
Pricing and Availability
Sonnet 5 is available immediately across all Anthropic plans — Free, Pro, Max, Team, and Enterprise — and is now the default model for Free and Pro users. [1] It is also available in Claude Code and through the Claude application programming interface (API) using the model identifier claude-sonnet-5. [1]
Through August 31, 2026, the model is priced at $2 per million input tokens and $10 per million output tokens. [1] After that date, pricing moves to $3 per million input tokens and $15 per million output tokens. [1]
Anthropic notes that Sonnet 5 uses an updated tokenizer — the component that converts text into the numerical units a model processes — which can increase token counts for the same input by roughly 1.0 to 1.35 times depending on content type. [1] The company says the introductory pricing is set to make the transition from Sonnet 4.6 roughly cost-neutral. [1]
Anthropic has also increased rate limits across its Chat, Cowork, Claude Code, and Claude Platform products to accommodate higher token usage at elevated effort levels. [1]
Safety Profile
Anthropic’s pre-deployment safety evaluations found that Sonnet 5 shows a lower overall rate of undesirable behaviors than Sonnet 4.6, including better resistance to malicious requests and prompt injection attacks — attempts by malicious content in the environment to hijack a model’s actions. [1] The model also shows lower rates of hallucination and sycophancy than its predecessor. [1]
However, Anthropic notes that Sonnet 5 scored somewhat higher on misaligned behavior than the more capable Opus 4.8 and Claude Mythos Preview models. [1]
On cybersecurity risk specifically, Anthropic says it did not deliberately train Sonnet 5 on cybersecurity tasks. [1] On evaluations testing the ability to develop software exploits — including one focused on Firefox browser vulnerabilities — Sonnet 5 was never able to produce a full working exploit, though it showed a slightly higher rate of partial success than Sonnet 4.6. [1] Anthropic attributes that marginal increase to general intelligence improvements rather than targeted training. [1]
Because of this, Anthropic has launched Sonnet 5 with cyber safeguards enabled by default, the same safeguards present in Opus 4.7 and 4.8. [1] The company says these safeguards are less strict than those applied to Fable 5, which block a wider range of cybersecurity tasks. [1] Sonnet 5 is part of Anthropic’s Cyber Verification Program, currently available on the native Claude Platform, the Claude Platform on Amazon Web Services, and Claude in Microsoft Foundry; Google Vertex support is listed as coming soon. [1]
Full evaluation details are available in the Claude Sonnet 5 System Card. [1]
Sources
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