Write cells

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 beyond them: previous contents are saved for undo_last, and it returns formula errors found after writing. It still doesn't state permission/account requirements or the overwrite footprint for large ranges (left to the schema's allow_large).

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 sentences, each earning its place: anchoring behavior, input parsing model, and undo/error side effects. Front-loaded with the core action and no filler.

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 6-param write tool with no output schema, the description covers the key behavioral facts an agent needs: overwrite semantics (undo saved), parses-as-UI input, and formula error reporting. Missing only auth/account and size-limit caveats, which the schema covers at 100%.

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 100%, so the baseline is 3; however the description adds parsing semantics not captured in the schema – that values are interpreted as UI input where formulas, dates, and percentages are recognized. That is meaningful extra meaning beyond the field docs.

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 (write values and/or formulas) plus the anchoring semantics (starting at the range's top-left cell), which distinguishes it from siblings like append_rows and fill_range. It does not name a sibling explicitly, so it falls just short of a 5.

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?

Explains how input is interpreted ('parsed like typing into the UI – formulas, dates, percentages work'), which implies usage, but gives no explicit when-to-use/when-not guidance or routing to alternatives such as append_rows or fill_range. Usage is implied rather than stated.

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