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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world. The description adds genuinely new behavioral context beyond that: 'Nothing is reserved or charged: the person completes it themselves,' which clarifies the side-effect boundary, plus the need to relay Spanish instructions. It stops short of describing error behavior for an invalid slug.

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 tight sentences, front-loaded with what the link is and then branching into the paid and free cases. The 'Spanish instructions to relay' note is an embedded operational instruction rather than prose filler, so it earns its place.

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 return-value burden by describing the link itself and how it differs for paid vs free events. Combined with 100% schema coverage and full annotation coverage, an agent has what it needs to call this 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 coverage is 100%, so each parameter is already documented, including that quantity and ticket_type_id are 'For paid events.' The description reinforces this conditional scoping ('checkout opens with the ticket type and quantity already chosen') but adds little syntax or default detail beyond the schema.

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 resource ('the link a person opens to buy tickets or register') and distinguishes two behavior modes (paid checkout vs free registration page). It doesn't name any sibling tool, so the agent gets no explicit routing vs get-event or draft-event, but the purpose itself is unambiguous.

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?

The paid/free distinction implicitly tells the agent when quantity and ticket_type_id matter, which is useful conditional guidance. However there is no explicit 'use this when' statement, no prerequisites, and no comparison to the sibling tools, so usage must be inferred.

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