我们推出了 Claude Sonnet 5（claude-sonnet-5），这是我们 Sonnet 模型系列的下一代产品，首发定价为每百万 Token 2 美元 / 10 美元（已于 8 月 10 日成为标准价格）

我们已推出 Claude Sonnet 5（claude-sonnet-5），这是 Sonnet 模型系列的下一代产品，首发定价为每百万 Token 2 美元 / 10 美元（已于 2026 年 8 月 10 日调整为标准价格）。Claude Sonnet 5 支持 100 万 Token 的上下文窗口、128k 最大输出 Token，并支持与 Claude Sonnet 4.6 相同的工具和平台功能，但 Priority Tier 除外，该功能在 Claude Sonnet 5 上不可用。迁移时适用三项行为变更：自适应思考现默认开启；手动扩展思考（thinking: {type: "enabled", budget_tokens: N}）已移除，并返回 400 错误（该功能在 Sonnet 4.6 上已弃用）；将采样参数（temperature、top_p、top_k）设置为非默认值会返回 400 错误。Claude Sonnet 5 还使用新的分词器，对相同文本产生的 Token 数量大约增加 30%。具体增幅取决于内容和负载形态。有关详细信息和迁移指南，请参阅《Claude Sonnet 5 的新特性》。有关行为差异和模型特定提示模式，请参阅《Claude Sonnet 5 提示指南》。Claude Managed Agents 会话事件流现支持事件增量。可通过在 GET /v1/sessions/{session_id}/events/stream 上使用 event_deltas[] 查询参数来选择启用。event_start 和 event_delta 事件会在完整的 agent.message 事件到达之前，预览代理消息生成时的文本。Claude Managed Agents 的会话列表现支持向后分页。GET /v1/sessions 在返回 next_page 游标的同时返回 prev_page 游标；将其作为 page 参数传递即可返回上一页。请参阅《分页》。创建 Claude Managed Agents 会话时，您现在可以覆盖该会话的代理配置。传入 type: "agent_with_overrides" 的 agent 参数，即可为单个会话替换模型、系统提示、工具、MCP 服务器或技能。代理本身保持不变。Claude Managed Agents 的 vault 现支持在环境变量凭据（“环境变量”选项卡）上设置 injection_location 设置。该设置控制凭据值在出口时是否被替换到代理的出站请求标头、请求正文或两者中。Claude Managed Agents 的 Webhook 现覆盖代理、部署和部署运行的生命周期。您可以响应新发布的代理版本、暂停的部署或失败的定时运行，而无需轮询。请参阅《订阅 Webhook》中的“代理事件”“部署事件”和“部署运行事件”选项卡。

We've launched Claude Sonnet 5 (claude-sonnet-5), the next generation of our Sonnet model family, at introductory pricing of $2 / $10 per MTok (made the standard price on August 10, 2026). Claude Sonnet 5 supports a 1M token context window, 128k max output tokens, and the same set of tools and platform features as Claude Sonnet 4.6, except Priority Tier, which is not available on Claude Sonnet 5. Three behavior changes apply when migrating: adaptive thinking is now on by default; manual extended thinking (thinking: {type: "enabled", budget_tokens: N}) is removed and returns a 400 error (it was deprecated on Sonnet 4.6); and setting sampling parameters (temperature, top_p, top_k) to non-default values returns a 400 error. Claude Sonnet 5 also uses a new tokenizer that produces approximately 30% more tokens for the same text. The exact increase depends on the content and workload shape. See What's new in Claude Sonnet 5 for details and migration guidance. For behavioral differences and model-specific prompting patterns, see Prompting Claude Sonnet 5. Claude Managed Agents session event streams now support event deltas. Opt in with the event_deltas[] query parameter on GET /v1/sessions/{session_id}/events/stream. The event_start and event_delta events preview an agent message's text as it's generated, before the complete agent.message event arrives. Listing sessions for Claude Managed Agents now supports backward pagination. GET /v1/sessions returns a prev_page cursor alongside next_page; pass it as the page parameter to return to the previous page. See Pagination. When creating a Claude Managed Agents session, you can now override the agent's configuration for that session. Pass agent with type: "agent_with_overrides" to replace the model, system prompt, tools, MCP servers, or skills for a single session. The agent itself is unchanged. Claude Managed Agents vaults now support an injection_location setting on environment variable credentials (the Environment variable tab). It controls whether the credential's value is substituted, at egress, into the agent's outbound request headers, the request body, or both. Webhooks for Claude Managed Agents now cover the agent, deployment, and deployment run lifecycle. You can react to a newly published agent version, a paused deployment, or a failed scheduled run without polling. See the Agent events, Deployment events, and Deployment run events tabs in Subscribe to webhooks.