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

Annotations only say readOnlyHint=false and destructiveHint=false; the description adds the critical semantic that the hold is temporary, nothing is paid, the tickets are not the user's until a human completes checkout, and the hold auto-expires. That is exactly the behavior an agent needs beyond the structured hints.

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?

Front-loads the action and the single most consequential caveat (temporary, unpaid hold), then limits, then the out-of-scope fallback. No filler sentences; capitalization is used deliberately for the risk that matters most.

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?

No output schema exists, yet the description tells the agent the call returns a checkout URL — the one return value that matters. Combined with the hold semantics, scope limits, and the per-item ID sourcing from get_event_tickets in the schema, an agent has everything needed to 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 description coverage is already 100%, so the baseline is 3. The description adds a real constraint not present in the schema — the 10 ticket / 10 ticket-type cap per reservation — which meaningfully shapes how the tickets array must be populated.

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 ('Hold tickets for an event sold through this site') plus the return value (a checkout URL), and names the platform (Wix Events). It is clearly distinguishable from siblings like rsvp_event, create_checkout, or get_event_tickets.

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 defines the boundary condition: works only for events this site sells directly, and directs the agent to the event's own ticketUrl for events sold elsewhere (Sympla, Ingresse, Sesc). It also states the hard limits (max 10 tickets / 10 ticket types), so the agent knows when not to call it.

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