添加白板元素

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

注解已声明非只读、非幂等、非破坏性、非开放世界，安全侧负担较轻；描述补充了「坐标为无限画布世界坐标、省略坐标自动排列」这一行为特性。但未提及单次最多 200 个元素的批量上限，以及版本冲突（虽然写在 expectedVersion 的 schema 描述里，非描述本身）。

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?

仅两句，先用途后坐标语义，前置得当且无冗余解释。唯一可议之处是元素种类枚举几乎完整复述了 kind 的 enum，占用篇幅但信息增量有限。

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?

已有 output schema，返回值无需描述；expectedVersion 的冲突语义也已由 schema 承担。对一个批量写入工具而言，描述仍缺批量上限、权限要求以及「只追加不覆盖」的明确保证，整体够用但不够完整。

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 描述覆盖率仅 50%，描述部分弥补了 x/y 的语义（无限画布世界坐标、可省略并自动排布），这对调用者很有价值。但元素列表基本是复述 kind 的 enum，未对 mode、layout、points、branches 等未覆盖参数补充含义，补偿不完整。

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?

明确以具体动词「批量添加」加资源「白板元素」开头，并枚举了支持的九类元素（便签、文本、图形、箭头等）。与 add/update/delete_elements 三兄弟中后两者仅靠语义推断区分，未显式点名，但不影响调用者判断这是新增而非修改。

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?

描述隐含了用途（批量新增元素），并给出了一个关键使用条件——省略坐标时自动排列。但没有说明何时应改用 whiteboard_update_elements 或 whiteboard_align_elements，也没有交代前置条件（如是否需先 inspect 获取版本）。

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