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

The annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, so the safety profile is covered. The description adds useful behavioral context by clarifying that it returns per-slot capacity, taken spots, open spots, names, and notes, and that it requires the private organizer link and does not modify the sheet. It does not discuss auth beyond link possession or rate limits, so it is strong but not exhaustive.

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 short and front-loaded with the usage trigger before describing returned data and constraints. Every sentence contributes useful selection or invocation context, with only minor redundancy against annotations and schema that does not harm clarity.

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 one-parameter read-only tool with rich annotations and an output schema, the description supplies the necessary when-to-use guidance, return summary, and link-type constraint. No critical invocation detail 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?

The schema coverage is 100%, and the schema already documents manage_url as the private organizer link with an example and a warning that the public link does not work. The description reinforces the private-link requirement but adds no syntax, format, or validation detail beyond the schema, so baseline 3 is appropriate.

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 uses a specific verb and resource: it shows sign-up results and returns each slot with capacity, spots taken, open spots, names, and notes. It distinguishes the tool from create_signup_sheet by describing a read/view operation on a sheet made with that sibling, while update_signup_sheet is separately implied as the mutation path.

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 gives explicit triggers: use when the user asks who signed up, what is still open, or how many spots are left. It also states a clear exclusion: the public link does not work, only the private organizer link does, and it does not change the sheet.

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