# 文档变更分析
### 1. Overall Summary
文档将所有代码示例中的默认模型从 `claude-opus-4-6` 更新为 `claude-sonnet-4-5`，并修正了关于 "Prefilling"（预填充）功能的警告信息，明确指出该功能在 4.6 系列模型上已被禁用并会报错，暗示开发者应使用 4.5 版本或替代方案。
### 2. Key Themes
* **示例代码模型迁移**：在 curl、Python、 TypeScript、C#、Go、Java、PHP、Ruby 及响应示例中，将模型字符串/常量从 `claude-opus-4-6` 统一替换为 `claude-sonnet-4-5`。
* **Prefilling 功能限制澄清**：警告文案发生变化，删除了关于 "Claude Sonnet 4.5" 不支持 Prefilling 的描述，转而强调在 `Claude Opus 4.6` 和 `Claude Sonnet 4.6` 上使用该功能会返回 `400` 错误。
* **迁移指引**：新增了指向“迁移指南”的链接，推荐开发者查看以处理模型变更带来的影响。
### 3. Impact Level
**Medium**
**Reasoning:** 虽然主要是文档字符串的调整，但隐含了重要的功能变更。这表明 `claude-opus-4-6` 和 `claude-sonnet-4.6` 可能正在被弃用或不再支持 Assistant Prefilling 模式。依赖该功能的现有代码在升级到 4.6 模型时会直接报错，需要开发者干预。
### 4. Action Items
* **检查现有代码**：如果你在使用 `claude-opus-4-6` 或 `claude-sonnet-4.6` 并依赖 Assistant Prefilling 技术，请立即停止，否则会收到 400 错误。
* **调整模型选择**：如需继续使用 Prefilling，请将模型切换至 `claude-sonnet-4-5`（正如文档新示例所示）。
* **评估替代方案**：阅读[迁移指南](/docs/en/about-claude/models/migration-guide)并考虑改用 [Structured Outputs](/docs/en/build-with-claude/structured-outputs) 来实现类似效果。
💭 Model Reasoning
1. **Analyze the Request:**
* **Role:** World-class programmer.
* **Task:** Analyze documentation changes (1 page).
* **Input:** Diff of `build-with-claude/working-with-messages.md`.
* **Output Format:** Markdown (concise, insightful, developer-focused).
* **Language:** Chinese.
2. **Analyze the Diff:**
* **File:** `build-with-claude/working-with-messages.md`.
* **Changes:**
* Multiple code examples (curl, Python, TypeScript, C#, Go, Java, PHP, Ruby, Response) changed the model string from `claude-opus-4-6` to `claude-sonnet-4-5`.
* A `<Warning>` block text changed.
* Old: "Prefilling is deprecated and not supported on Claude Opus 4.6, Claude Sonnet 4.6, and Claude Sonnet 4.5..."
* New: "Prefilling is not supported on Claude Opus 4.6 and Claude Sonnet 4.6. Requests using prefill with these models return a 400 error..." + Added reference to a migration guide.
3. **Synthesize Findings:**
* **Overall Summary:** The documentation updates example code to use `claude-sonnet-4-5` instead of `claude-opus-4-6` and refines the warning regarding "Prefilling" (assistant prefilling) support. Specifically, it clarifies that prefilling returns 400 errors on 4.6 models but implies it might be supported on 4.5 (since the old text said "not supported on... Claude Sonnet 4.5" but the new text only lists 4.6 models). *Correction:* Let me re-read carefully.
* *Old text:* "Prefilling is deprecated and not supported on Claude Opus 4.6, Claude Sonnet 4.6, and Claude Sonnet 4.5."
* *New text:* "Prefilling is not supported on Claude Opus 4.6 and Claude Sonnet 4.6. Requests using prefill with these models return a 400 error."
* *Observation:* The new text removes "Claude Sonnet 4.5" from the "not supported" list. This is a subtle but crucial change. It suggests prefilling *is* supported on Sonnet 4.5, or at least, the warning specifically targets the 4.6 models now.
* *However*, looking at the code examples: They changed the example model from Opus 4.6 to Sonnet 4.5. If prefilling is still the topic being demonstrated (it seems to be a "prefilling" section given the context of assistant messages), and the warning says 4.6 throws errors, moving the example to 4.5 makes sense if 4.5 supports it.
* **Key Themes:**
* **Model Deprecation/Shift:** Shifting primary examples from Opus 4.6 to Sonnet 4.5.
* **Feature Availability/Policy:** Clarifying the status of "Prefilling" (assistant prefilling) - specifically noting it is disabled/throws errors on 4.6 models, while the example implies it works on 4.5.
* **Error Handling:** Explicitly mentioning 400 errors for invalid usage.
* **Impact Level:** Medium.
* *Reasoning:* While the code change is minor (updating model names), the semantic change in the warning message is significant. It indicates that prefilling behavior differs between model generations (4.5 vs 4.6). Developers relying on prefilling need to know which models support it to avoid 400 errors.
* **Action Items:**
* Review usage of Claude 4.6 models with prefilling.
* Check if the migration guide is needed if migrating from 4.6 to 4.5 or 3.5/4.2.
* Use Sonnet 4.5 if prefilling is required (implied by the context).
4. **Drafting the Response (in Chinese):**
* **Summary:** 文档更新将示例代码中的模型从 `claude-opus-4-6` 更改为 `claude-sonnet-4-5`，并更新了关于 "Prefilling"（预填充）技术的警告信息，明确了该功能在 4.6 版本模型上会返回 400 错误。
* **Key Themes:**
* 示例代码模型更新：将所有语言示例统一替换为 `claude-sonnet-4-5`。
* Prefilling 功能限制澄清：明确指出 Prefilling 在 `claude-opus-4-6` 和 `claude-sonnet-4.6` 上不受支持（会报 400 错误），且不再将 `claude-sonnet-4.5` 列入不支持名单（暗示 4.5 仍支持）。
* 迁移指引：新增了指向迁移指南的链接。
* **Impact Level:** Medium。
* *Reasoning:* 虽然只是字符串替换和警告文案调整，但这揭示了模型能力的变更。如果开发者使用 4.6 模型进行 Prefilling，代码将会中断（400 错误），需要迁移到 4.5 或其他方案（如 Structured Outputs）。
* **Action Items:**
* 如果正在使用 `claude-opus-4-6` 或 `claude-sonnet-4-6` 进行 Assistant Prefilling，请立即停止，否则会收到 400 错误。
* 考虑使用 `claude-sonnet-4-5` 继续使用 Prefilling 功能。
* 查阅迁移指南，评估是否改用 Structured Outputs 来替代 Prefilling。
5. **Refining the Output:**
Make it punchy and professional.
* *Draft check:* The change from "deprecated and not supported on... 4.5" to "not supported on... 4.6" suggests 4.5 is the safe harbor for prefilling now. The code change supports this by demonstrating the feature on Sonnet 4.5.
6. **Final Polish (Markdown format):**
(Self-Correction during drafting: Ensure the distinction between the code change and the warning change is clear. The code change reinforces the warning change.)
* **Summary:** 文档将示例代码中的默认模型从 `claude-opus-4-6` 迁移至 `claude-sonnet-4-5`，并明确了 "Prefilling"（预填充）功能在 4.6 版模型中已被禁用。
* **Themes:**
* 模型版本更迭：代码示例全面转向 Sonnet 4.5。
* 功能行为变更：澄清 Prefilling 在 Opus 4.6 和 Sonnet 4.6 上会直接返回 400 错误，而不再提及 4.5 不支持此功能。
* 迁移支持：添加了迁移指南链接。
* **Impact:** Medium (功能性限制)。
* **Actions:**
* 避免在 4.6 模型中使用预填充。
* 迁移至 4.5 或 Structured Outputs。
Let's write the final Chinese response.