list_tables

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

readOnlyHint=true already tells the agent this is a safe read, so the burden is lower. The description adds real behavioral context (table names and sheet names are independent, so a missing tab may simply mean no table is registered there), but says nothing about the shape of the result, ordering, or handling of workbooks with no tables.

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 short sentences, front-loaded with the core mapping behavior before the parameter guidance. Minor redundancy between "these names are distinct" and "neither name implies the other," but nothing that wastes meaningful space.

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?

For a two-parameter read-only listing tool with no output schema, the description covers purpose, the key naming gotcha, and the sheet_name default comprehensively. The only shortfall is that it doesn't state what the listing contains per table (range/ref), which an agent must infer from the opening clause.

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 50%: filepath is well documented in the schema, while sheet_name has no schema description at all. The description compensates for that gap by explaining what omitting sheet_name does (whole-workbook search) and what its absence implies operationally, which is exactly the missing semantics.

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?

The description names a specific verb and resource ("Map native table names to worksheet tabs and ranges") and clarifies the mapping nature of the output. It distinguishes the tool conceptually from a plain sheet lister by stressing that table and worksheet names are distinct, though it doesn't name the sibling tools it differs from (e.g. list_all_sheets, list_named_ranges).

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?

It gives one concrete usage trigger — omit sheet_name to search the whole workbook, especially after a missing-tab error — which is genuinely actionable. However, there is no explicit guidance on when to prefer this over adjacent tools like read_excel_table, query_table, or list_all_sheets, leaving the main routing decision implicit.

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