我们发布了Claude Opus 5（claude-opus-5），相比Claude Opus 4.8有显著改进。

我们已推出 Claude Opus 5（claude-opus-5），这是对 Claude Opus 4.8 的跨越式改进。Claude Opus 5 支持 100 万 token 上下文窗口（默认和最大值均为该值）、12.8 万最大输出 token，并默认开启思考功能，定价为每百万 token 5 美元 / 25 美元，与 Claude Opus 4.8 相同。该模型已在 Claude API、Amazon Bedrock 上的 Claude、Google Cloud 上的 Claude 以及 Microsoft Foundry 上的 Claude 中提供。请参阅《Claude Opus 5 的新特性》了解新功能、行为变更和迁移指南，以及《模型概览》了解完整规格。在 Claude Opus 5 上，仅允许在 effort 为 high 或更低级别时禁用思考：使用 effort xhigh 或 max 时，若传入 thinking: {"type": "disabled"} 将返回 400 错误，这是与 Claude Opus 4.8 的破坏性变更。详情见《Claude Opus 5 的新特性》。Effort 是引导 Claude Opus 5 的主要控制参数：该模型支持完整的 effort 阶梯（low、medium、high、xhigh、max），其中 max 用于能力关键型工作。对话中途工具变更现已在 Claude Fable 5、Claude Mythos 5、Claude Opus 4.8 和 Claude Opus 5 上进入测试阶段：可在对话轮次之间添加或移除工具，同时保留提示缓存。请在请求中包含 mid-conversation-tool-changes-2026-07-01 测试版标头。fallbacks 参数现在支持 "default" 模式，该模式会根据拒绝类别应用 Anthropic 推荐的备用模型。服务端备用功能处于测试阶段，"default" 模式需要 server-side-fallback-2026-07-01 测试版标头。请参阅《拒绝与备用》。我们已移除 Claude Opus 4.7 的快速模式。向 claude-opus-4-7 发送带有 speed: "fast" 的请求现在会返回错误；与 Claude Opus 4.6 不同，它们不会回退到标准速度。Claude Opus 4.7 本身仍以标准速度可用。要继续使用快速模式，请迁移至 Claude Opus 5 或 Claude Opus 4.8。更多信息请阅读《快速模式》。

We've launched Claude Opus 5 (claude-opus-5), a step-change improvement over Claude Opus 4.8. Claude Opus 5 supports a 1M token context window (both the default and the maximum), 128k max output tokens, and thinking on by default, at $5 / $25 per MTok, the same pricing as Claude Opus 4.8. It's available on the Claude API, Claude in Amazon Bedrock, Claude on Google Cloud, and Claude in Microsoft Foundry. See What's new in Claude Opus 5 for new features, behavior changes, and migration guidance, and the models overview for complete specs. On Claude Opus 5, disabling thinking is allowed only at effort high or below: thinking: {"type": "disabled"} with effort xhigh or max returns a 400 error, a breaking change from Claude Opus 4.8. See What's new in Claude Opus 5. Effort is the primary control for steering Claude Opus 5: the model supports the full ladder (low, medium, high, xhigh, max), with max for capability-critical work. Mid-conversation tool changes are now in beta on Claude Fable 5, Claude Mythos 5, Claude Opus 4.8, and Claude Opus 5: add or remove tools between turns of a conversation while preserving the prompt cache. Include the mid-conversation-tool-changes-2026-07-01 beta header in your requests. The fallbacks parameter now supports a "default" mode, which applies Anthropic's recommended fallback models by refusal category. Server-side fallback is in beta, and the "default" mode requires the server-side-fallback-2026-07-01 beta header. See Refusals and fallback. We've removed fast mode for Claude Opus 4.7. Requests to claude-opus-4-7 with speed: "fast" now return an error; unlike Claude Opus 4.6, they do not fall back to standard speed. Claude Opus 4.7 itself remains available at standard speed. To continue using fast mode, migrate to Claude Opus 5 or Claude Opus 4.8. Read more in Fast mode.