send_email

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

没有 annotations，因此描述承担了行为披露责任。它补充了“立即投递”、to 不能为空、cc 可选以及人工确认时应改用存草稿等行为信息。但未提及发送失败行为、权限要求或幂等性等细节，信息有限但不算误导。

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

描述只有一句话，核心信息“直接发送（立即投递）”前置，随后是参数约束和替代方案，没有冗余内容，每个部分都有价值。

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

对于简单的发送邮件工具，描述已覆盖关键调用前提（to 必填、cc 可选）、行为特征（立即投递）和替代路径（save_draft），且存在输出 schema 无需赘述返回值。缺少个别的失败或重试说明，但整体足以支持正确调用。

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema 描述覆盖率为 0%，描述本应充分补偿参数语义，但只说明了 to 不能为空、cc 可选，这些信息大多已隐含在 schema 的 required 和 default 中。subject 和 body 的格式或含义没有额外说明。

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

描述以“直接发送邮件（立即投递）”明确说明了动作、对象和即时性特征，并用“如需人工确认请改用 save_draft”与兄弟工具做了区分。即使不看工具名，也能准确理解该工具的用途。

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

描述明确给出了人工确认场景下应使用 save_draft 的替代方案，并通过“立即投递”暗示了与定时发送等工具的差异。但没有显式说明何时使用 schedule_send 或 batch_send，缺少系统性排除。

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.