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

Annotations cover the safety profile (readOnly=false, destructive=false, openWorld=true), and the description adds genuinely new behavior: it sends no message, so it runs without asking first, plus the Cotlet API key/access requirement. This is useful beyond the structured fields, though it omits any error or idempotency behavior.

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?

Purpose is front-loaded and the sentences are mostly earning their place (no-message behavior, auth requirement). There is mild redundancy between 'Mark a guest as invited to an event' and 'Adds an event to the events a guest is invited to', which restate the same action.

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 two-parameter mutation with annotations and no output schema, the description covers purpose, side effects, confirmation behavior, and auth needs. Nothing critical for correct invocation is missing; it just lacks return/confirmation details, which is acceptable given no output schema.

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 both event_id and guest_id (obtained from list_events and list_guests) are already documented in the schema. The description adds no syntax or format detail beyond that, so the 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?

States a specific verb and resource ('Mark a guest as invited to an event') and clarifies the effect ('so they can RSVP'). This cleanly distinguishes it from siblings like zola_add_guest (creates a guest) and zola_record_rsvp (records an RSVP), even without naming them.

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?

Gives clear context for when to use it ('the choice you make on the "Invite Guests to Events" tab') and the underlying rule ('Guests can only RSVP to events they are invited to'). It does not explicitly name alternative tools (e.g., zola_add_guest for creating new guests), so it stops short of full routing guidance.

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