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

Annotations already cover readOnly, idempotent, non-destructive, and closed-world traits, so the bar is lower. The description still adds real context by disclosing aggregation semantics (what 'responded' vs 'outstanding' count, how response rate is computed), what is deliberately excluded (guest identities, individual event answers), and an auth requirement.

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 most important content (what is returned) is front-loaded in the first sentence, and the remaining sentences explain counting semantics and exclusions without padding. Slightly dense phrasing, but every sentence contributes information.

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 no output schema, the description carries the full burden of explaining return values, and it does so thoroughly, including the exact meaning of each count and the response-rate formula. Sign-in requirement and exclusions round out what an agent needs to call and interpret it correctly.

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?

There is a single parameter with 100% schema coverage; the schema already documents that wedding_id is needed when the account manages multiple weddings. The description adds no further parameter meaning, so the baseline of 3 applies.

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 ('Returns aggregate wedding statistics') and enumerates exactly what the aggregate contains: guest totals by age band, RSVP counts, event counts, and registry progress. This clearly differentiates it from the detail-oriented siblings like get_my_wedding and the identity-level list_my_guests.

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?

Usage is only implied: the aggregate framing and the 'Requires sign-in' note suggest it is a dashboard/summary tool. There is no explicit when-to-use guidance, no statement of when to prefer it over get_my_wedding or list_my_guests, and no alternatives named.

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