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 adds genuinely new context beyond the structured fields: the auth requirement ('needs the Cotlet API key with access to this app') and the default behavior that contact details are withheld unless include_contact is true. Pagination/rate-limit behavior is still undisclosed.

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 return fields are stated twice in near-identical terms ('Guests with their list... events invited to and RSVP state' then 'the guests on your guest list, each with the list they are on, the events they are invited to and their reply per event'), which is redundant. The lead sentence is front-loaded, but the duplication costs it.

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 correctly carries the burden of describing the return shape and does so explicitly. It covers auth, defaults, and item structure; the only notable omissions are pagination/volume behavior, which is minor for a read-only listing tool with three well-documented optional filters.

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 list, search, and include_contact are already fully documented in the schema. The description only restates the include_contact conditional, adding no syntax or format detail beyond what the schema provides, so the baseline 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?

States a specific verb+resource (lists guests) and enumerates exactly what each item contains: list membership, invited events, and per-event RSVP state. This is far clearer than a bare 'list guests', but it names no sibling for differentiation, so it stops just short of a 5.

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 notes that guest_id from each item should be used with the other tools, which implies this is a source/discovery call, and it states the API key prerequisite. There is no explicit when-to-use vs when-not guidance and no named alternative (e.g. zola_track_rsvps or zola_list_events), so usage is only implied.

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