Defined names

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

Annotations already declare destructiveHint=true and readOnlyHint=false; the description adds valuable nuance by explaining that mutating names can break VBA code and formulas, and by explicitly flagging that the list action is side-effect-free. No contradiction with annotations.

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?

Three tightly written sentences: the first states function, the second provides necessary risk context, and the third gives actionable parameter guidance. Every sentence earns its place and key material is front-loaded.

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?

Given that the input schema documents all parameters and an output schema exists, the description covers everything an agent needs: what the tool does, when list is safe, why mutations are risky, and how to construct a valid refers_to argument. No critical gaps remain.

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 coverage is 100%, so the baseline is 3. The description adds practical meaning beyond the schema by explaining that refers_to must contain sheet names and dollar signs (Data!$A$1:$A$50) and by clarifying the behavioral difference of the action='list' value.

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?

Clearly states the resource (workbook defined names) and the exact actions (lists, adds, removes). The TaxRate example makes the concept immediately recognizable and distinguishes this tool from sibling sheet/cell/module tools.

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?

Provides clear context on safe usage ('action='list' changes nothing') and on how to format refers_to, which is essential for calling the tool correctly. It does not explicitly name alternatives or exclusions, but no competing sibling tool exists for this specific resource.

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