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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description goes beyond by detailing the access model (created vs. user-picked), the alternative input methods (spreadsheetId or sheetUrl), and the specific error-recovery instruction. It also discloses the return format (2-D array). This adds meaningful behavioral context beyond the 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 about four sentences, each packed with necessary information. It starts with the core action, then access conditions, then error handling, then return type. No fluff or redundancy; every sentence earns its place.

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 read tool with no output schema, the description fully equips an agent: it covers input alternatives, how to resolve not-found errors, and the return format. It also references sibling tools (list_drive_files, create_sheet) for id sourcing. Nothing essential for a correct call is missing.

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?

Although schema description coverage is 100%, the description adds crucial relational semantics: it explains that spreadsheetId and sheetUrl are alternatives and where to obtain the id (from create_sheet or list_drive_files). It also clarifies the range parameter's default. This goes beyond the schema's per-parameter descriptions by explaining the interaction between parameters.

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 ('Read') and resource ('cells from a Google Sheet'), and clarifies the scope (sheets Hermoso can reach). It stands out from siblings like update_sheet or append_to_sheet by making the read-only nature explicit. The mention of the access model and the error-handling path further disambiguates its purpose.

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 explicitly explains when the tool works (sheets created by Hermoso or user-picked) and how an existing sheet becomes readable, pointing to list_drive_files for finding the id. It also advises the agent to ask the user to pick the file on a not-found error rather than retrying, which is clear guidance on when NOT to use the tool. This is strong contextual routing.

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