业务字段寻址

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

readOnlyHint 已说明只读属性，描述中“解析”“直接走内部映射 API”也表明无副作用；未描述可能的失败/边界行为，但低风险只读操作下已有足够透明度。

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?

两句话直接说明核心功能、输入来源和对比优势，没有冗余信息，结构紧凑。

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?

在已有输出 schema 的情况下无需解释返回值；但未说明多表/多 tab 场景下如何通过 tab_id/table_index 消歧，且未提及与 vtable_headers/read_cells 的协作方式，完整性有缺口。

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?

必填参数 field 和 record_index 有明确说明（含 record_index 从 0 起、不含表头）；但可选参数 tab_id 和 table_index 完全没有语义说明，在 schema 覆盖率为 50% 时描述未能完全弥补歧义。

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?

描述明确说明工具用途：按业务字段和记录索引解析单元格地址（col/row）及当前值；并通过与 find_cell 的对比（不依赖文本、走 VTable 内部映射）清晰区分了同类工具。

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?

给出了相对 find_cell 的使用理由和稳定性优势，暗示需要按字段+索引稳定定位时应使用本工具；但未明确说明何时应使用其他替代工具，也未解释 tab_id/table_index 的选择场景。

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