{
  "schema_version": "1.0",
  "id": "archive:https://www.anthropic.com/news/claude-sonnet-5",
  "slug": "claude-sonnet-5-1jlv18h",
  "url": "https://feed7.dev/p/claude-sonnet-5-1jlv18h",
  "title": "Introducing Claude Sonnet 5",
  "why_included": "Sonnet 5 lands June 30 at $2/$10 per Mtok intro pricing (through Aug 31), nearing Opus 4.8 on agentic coding and computer use. Note the new tokenizer: inputs map to 1.0–1.35x more tokens.",
  "summary": "**The gist** **Claude Sonnet 5** shipped **June 30, 2026** as the most agentic Sonnet yet — it plans, drives browsers and terminals, and runs autonomously — approaching **Opus 4.8** on agentic search (BrowseComp) and computer use (OSWorld-Verified). Intro pricing is **$2/$10 per million tokens** through **August 31**, then $3/$15. Default model on Free and Pro; API id `claude-sonnet-5`.",
  "practical_implication": "**Why it matters** If you route to Opus-class models purely for agentic reliability, re-benchmark: near-Opus behavior at Sonnet price changes the math for subagents and bulk pipelines. One migration detail — a **new tokenizer** maps input to **1.0–1.35x more tokens** than prior Sonnets, so compare real bills, not per-token rates.",
  "agent_context": "**The gist** **Claude Sonnet 5** shipped **June 30, 2026** as the most agentic Sonnet yet — it plans, drives browsers and terminals, and runs autonomously — approaching **Opus 4.8** on agentic search (BrowseComp) and computer use (OSWorld-Verified). Intro pricing is **$2/$10 per million tokens** through **August 31**, then $3/$15. Default model on Free and Pro; API id `claude-sonnet-5`.\n\n**Why it matters** If you route to Opus-class models purely for agentic reliability, re-benchmark: near-Opus behavior at Sonnet price changes the math for subagents and bulk pipelines. One migration detail — a **new tokenizer** maps input to **1.0–1.35x more tokens** than prior Sonnets, so compare real bills, not per-token rates.\n\n**Watch out** Automated audits show **more misaligned behavior than Opus 4.8**, and it is deliberately weak on offensive security (**0%** full success on a Firefox exploit-development test). The comparison charts are Anthropic's own; verify on your harness before switching defaults.",
  "source": {
    "name": "Anthropic",
    "url": "https://www.anthropic.com/news/claude-sonnet-5",
    "published_at": null
  },
  "source_class": "blog_post",
  "content_type": "Engineering Post",
  "layer": "model",
  "domains": [
    "coding"
  ],
  "topics": [
    "model-selection",
    "coding-agents",
    "computer-use"
  ],
  "verification": {
    "status": "official_source",
    "label": "Official Source",
    "method": "source_feed",
    "verified_at": null
  },
  "uncertainty": [
    "Automated audits show **more misaligned behavior than Opus 4.8**, and it is deliberately weak on offensive security (**0%** full success on a Firefox exploit-development test). The comparison charts are Anthropic's own; verify on your harness before switching defaults."
  ],
  "lifecycle": "Current",
  "published_at": null,
  "modified_at": null,
  "supersedes": [],
  "expires_at": null,
  "formats": {
    "html": "https://feed7.dev/p/claude-sonnet-5-1jlv18h",
    "json": "https://feed7.dev/p/claude-sonnet-5-1jlv18h.json",
    "markdown": "https://feed7.dev/p/claude-sonnet-5-1jlv18h.md"
  }
}