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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is clear. The description adds useful behavior: formulas return their displayed value and there's a 10,000 cell limit per call. But it doesn't mention return format or error behavior, which is a gap for a read tool without an output schema. With annotations covering safety, a 3 is appropriate.

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?

Four short sentences, front-loaded with the core purpose, then key behaviors. Zero waste; every sentence adds useful information.

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 is read-only with annotations covering safety and a schema at 75% coverage, the description covers the essentials: what it reads, range omission behavior, formula handling, and a size limit. Missing details like return format or pagination are minor because there's no output schema and the annotations handle safety. A 4 reflects completeness with minor gaps.

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 75%, so the schema already documents parameters like range, sheet, and mailbox reasonably well. The description adds minor details: omitting range reads the used range, and formulas return displayed values. However, it doesn't clarify the workbookId parameter or add significantly more than the schema provides. Baseline 3 is appropriate when schema is mostly complete.

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 clearly states a specific verb (read) and resource (cell values from a worksheet in an Excel workbook), which distinguishes it from siblings like read_google_sheet_range and get_excel_workbook. No ambiguity about what the tool does.

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 provides one implied usage detail: 'Omit range to read whatever is occupied.' However, it does not explicitly compare to alternatives such as read_google_sheet_range or mention when to use this instead of getting the whole workbook. No when-not conditions are given.

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