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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered. The description adds real context beyond that: guests under 13 and guests with unconfirmed ages are excluded, notes and dietary details are omitted from results, and authentication is required before calling.

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 short sentences ordered by importance: what is returned, how to narrow it, what is excluded and the auth requirement. Every sentence carries distinct information with no redundancy.

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 does well by naming the returned fields and the exclusions, so an agent knows the shape of the response. It does not mention result limits or pagination, which is the only notable gap.

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 each parameter is already documented, including the enum for rsvp_status. The description confirms the filter dimensions (RSVP status, name) but adds no syntax or matching nuance beyond what the schema states.

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 names a specific verb and resource ('Lists guests in the selected wedding'), scopes it by age (13+) and enumerates the fields returned (contact details, RSVP status). An agent can immediately distinguish this from sibling mutations like add_my_guest or update_my_guest.

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 states that filters are optional and that sign-in is required, which implies the calling context, but it never says when to reach for this tool versus sibling listers or how to follow up (e.g. update_my_guest to change an RSVP). Usage is implied rather than explicit.

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