sheets_update_values

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

Annotations already declare idempotentHint=true and destructiveHint=false. The description adds valuable behavioral context beyond these: row-count matching for fixed ranges, auto-expansion for flexible ranges, and the warning that empty rows in the data array still count as rows. This is significant practical information that annotations do not cover.

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?

The description is appropriately sized and front-loaded: one clear purpose sentence followed by three bullet-point examples and a critical warning. Every sentence earns its place, with no redundancy or filler. The structure makes the content easy to parse.

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?

The description covers the most critical usage nuances (fixed vs flexible ranges, row-count rules) that are not obvious from the schema or annotations. It does not mention return values, but the absence of an output schema and the mutation nature make that less essential. Overall, it gives an agent enough context to use the tool correctly in most scenarios.

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?

With 100% schema description coverage, the baseline is 3. The description enhances the parameter understanding with concrete examples for the 'range' parameter, such as avoiding 'A42:E53' and using 'A42' to prevent row-count mismatch errors. This goes beyond the schema's formal definition and gives the agent actionable guidance.

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 the tool's function: 'Update values in a specified range of a Google Sheets spreadsheet.' The examples further clarify the exact behavior (fixed vs flexible ranges) and distinguish it from append/clear/read tools by focusing on overwriting existing 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 provides detailed usage examples and tips (e.g., using 'A42' for rows 42-74) but does not explicitly contrast with sibling tools like sheets_batch_update_values or sheets_append_values. When to choose this tool is implied rather than directly stated, leaving the agent to infer the differentiation.

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