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

With no annotations provided, the description carries the full behavioral burden. It clearly discloses that this is a read-only operation ('Read... without reading cells') and describes what is returned (worksheets and occupied ranges). It doesn't detail output shape or hidden-sheet handling, but it gives enough clarity about scope and safety.

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?

Two sentences, front-loaded with the core purpose and immediately followed by actionable guidance. Every sentence earns its place, with zero redundant phrasing.

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?

There is no output schema, so the description must convey return value semantics, which it does at a high level (worksheets and occupied ranges). It is sufficient for the intended 'discover then read' workflow, though a bit more detail about the return format would make it fully complete.

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 description coverage is 50%: mailbox is well documented in the schema, but workbookId has no description at all. The tool description implies workbookId refers to the target workbook but does not explain how to obtain it (e.g., from list_excel_workbooks). The description adds only minimal value for the undocumented parameter.

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 states a specific verb and resource ('Read a workbook's shape') and distinguishes it from cell-reading tools by explicitly saying 'without reading cells'. It also clarifies the deliverable: worksheets and their occupied ranges, which sets it apart from list_excel_workbooks (which lists workbooks) and read_excel_range (which reads cells).

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?

The description gives explicit workflow guidance: 'Call this first to learn what sheets exist and how far the data reaches, then read from the one you want.' This clearly establishes when to use it, though it does not name a specific alternative tool (e.g., read_excel_range) or state when NOT to use it.

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