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

Annotations already declare destructiveHint=true and readOnlyHint=false, but the description adds real value: it warns the replacement happens 'without warning' and explains value-interpretation behavior tied to valueInput. It does not cover auth/permission requirements, but with annotations carrying the safety profile this is solidly above baseline.

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 tight sentences with the destructive warning front-loaded and zero filler. Every sentence carries information the agent needs before calling.

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 destructive write tool with no output schema, the description covers the critical destruction and valueInput semantics. It omits range format and permission/mailbox prerequisites, which leaves a small gap for a 5-param mutation tool.

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 only 20% (mailbox alone), so the description must compensate and it only partially does. It clarifies the valueInput semantics ('interpreted as if typed unless RAW'), which is the trickiest param, but range notation (A1?), values shape, and spreadsheetId are left undocumented in both schema and description.

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?

States a specific verb (overwrite) and resource (cells in a range), and the word 'overwrite' implicitly distinguishes it from append_google_sheet_rows and clear_google_sheet_range. However, it never names a sibling tool, so the differentiation is left to inference rather than stated.

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?

Gives actionable pre-call guidance: 'read the range first if you need to keep any of it.' That is clear context for a destructive write. It stops short of routing between alternatives (e.g., append vs overwrite, or the Excel equivalent), so no explicit exclusions are provided.

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