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

Annotations already cover the safety profile (readOnly, non-destructive, openWorld), yet the description adds real behavioral context: undelivered-invite guests are listed first, shareable-link guests appear only after RSVP, and it states the auth requirement (Cotlet API key with app access). Pagination for a potentially large list is the notable omission.

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 purpose is front-loaded and most sentences carry distinct information (returned fields, ordering, counts, timing, auth). It is somewhat dense and opens with a fragment, but there is little waste.

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 simple list tool with no output schema, the description fully carries the return-value burden: it describes the fields returned, the counts block, the ordering rule, and the delayed appearance of shareable-link guests. An agent has everything needed to interpret results.

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% and the two parameters (event_id, rsvp) are fully documented in the schema itself, so the baseline is 3. The description does not add syntax or filtering nuance beyond what the schema already provides.

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 ('Returns the guests of one event') and enumerates the returned fields (name, email/phone, RSVP, party count, comment) plus a counts block. It is clear what the tool does, though it never explicitly distinguishes itself from sibling evite_export_guest_list.

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 by the schema's rsvp filter and the reference to the 'View Guest List' view. There is no explicit when-to-use / when-not-to-use statement or routing to alternatives like evite_export_guest_list.

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