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

With no annotations, the description fully clarifies the tool's behavior: the hold is temporary, nothing is paid, a checkout URL is returned, and the hold expires if not completed. It also states restrictions on event source and limits on tickets.

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 sentences: first sentence states the main action and return value, second details the temporary nature, third adds limits and alternative tool usage. Every sentence adds necessary information without 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?

Given the tool's simplicity (2 params, no output schema) and full schema coverage, the description covers all necessary aspects: purpose, constraints, alternative scenarios, and what the user gets (checkout URL). No gaps for an AI agent to select and invoke 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?

Schema covers both parameters with descriptions. The description adds value beyond the schema by stating constraints (max 10 tickets and 10 ticket types) and clarifying the purpose of the tickets array as 'Ticket types and quantities to hold.' This provides context that the schema alone does not give.

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 clearly states the action: 'Hold tickets for an event sold through this site (Wix Events) and return a checkout URL.' It specifies the resource (event tickets) and the verb (hold and return URL), and distinguishes it from siblings like 'create_booking' and 'rsvp_event' by focusing on temporary holds, not final bookings.

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?

Explicitly tells when to use this tool ('Only works for events this site sells directly') and when not to ('for events sold elsewhere... use the event's own ticketUrl instead'). Also covers constraints: max 10 tickets and 10 ticket types, hold is temporary and expires.

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