Write to a range in a Google Sheet

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

Annotations already declare destructiveHint, idempotentHint, and openWorldHint, but the description adds critical behavioral details beyond those: writing over filled cells is refused first (naming the count), a confirm:true flag is required to proceed, and the result is read back from the sheet so the agent reports actual sheet state. These specifics materially modify expected behavior and are not derivable from annotations.

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 long but highly informative, and each sentence adds value. The purpose is front-loaded, the alternative is named, and edge cases (refusal, confirmation, read-back) are covered. While slightly wordy, it is not bloated or repetitive; the structure flows from purpose to mechanics to safety verification.

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?

With 7 parameters, no output schema, and rich annotations, the description covers the critical aspects: what the tool does, when to use it, the confirmation gate, and the read-back guarantee. It does not explicitly explain the difference between sheetUrl and spreadsheetId, but those are conventional and likely self-evident. Overall, an agent has enough to call this correctly without external documentation.

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 coverage is 71%, and the description significantly enriches the main parameters: it gives concrete range examples ('B2:C5', 'Q3 Report!B2'), explains the anchor-cell behavior, clarifies that values must be an array of row arrays, and explains confirm is required only when overwriting. It also details the updates parameter for multiple disjoint ranges. The only parameters left untouched are sheetUrl and spreadsheetId, which are standard identifiers; the description compensates well for the schema gaps.

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 ('CORRECT cells'), the resource ('a Google Sheet'), and the precise operation ('write values to an exact range, overwriting whatever is there'). It explicitly contrasts with append_to_sheet, naming the sibling and the exact limitation it overcomes, so an agent can distinguish this tool without ambiguity.

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 when-to-use guidance: 'This is the fix append_to_sheet cannot make' and explains the failure mode appending would cause. It also specifies the confirmation workflow for overwriting non-empty cells ('show the user that, get a yes, then call again with confirm:true'), leaving no ambiguity about prerequisites or safe invocation.

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