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

With no annotations, the description carries the full burden. It clearly states it reads without reading cells, signaling a non-destructive structural read, and discloses the returned data (tabs, sizes, named ranges). This is sufficient transparency for a read-only tool.

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 with no filler. Purpose and usage are front-loaded, and every word contributes to understanding. The structure is optimal for the agent.

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 the tool's simplicity (2 params, no output schema), the description covers the core use case and expected output. It could mention error conditions or limits, but for a structural read operation, it is adequate and distinct from siblings.

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?

The mailbox parameter is well-described in the schema, but spreadsheetId has no description. The tool description adds context about the output (structure) but doesn't elaborate on spreadsheetId semantics or format. Since schema coverage is only 50%, the description should compensate, but it mostly relies on the parameter name.

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 ('Read') and resource ('spreadsheet's shape') with concrete elements: tabs, sizes, and named ranges. It explicitly contrasts with reading cells and ties to a subsequent read-range action, clearly distinguishing it from read_google_sheet_range and list_google_spreadsheets.

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 guidance: 'Call this first to learn what tabs exist, then read a range from the one you want.' This provides a strong when-to-use instruction relative to read operations. It doesn't explicitly list alternatives or exclusions, but the sequencing advice is clear enough to steer an agent.

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