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

Annotations already declare readOnlyHint=true, so the read-only safety profile is covered. The description adds the underlying Neon endpoint and the shape of each returned registration, but says nothing about pagination limits, default sort, or result volume — modest additional value, appropriate for a 3.

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?

A single tight sentence with the core purpose front-loaded and the returned fields listed compactly; the trailing endpoint reference is short and useful for tracing. No padding or 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?

For a read-only list tool with a fully described schema and annotations covering safety, the description supplies what remains: the contents of each registration record, compensating for the absent output schema. Missing only pagination/sort defaults, which the schema partially covers.

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 all five parameters (including page/page_size semantics and the sort_direction enum) are already documented in the schema. The description only hints at registrant_account_id as an optional narrowing filter, adding little 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 verb and resource ('List the registrations for one event') and enumerates the data returned (registrant account, tickets/attendees, amount, payments), which lets the agent distinguish it from the sibling neon_list_account_event_registrations scoped per account. However, it never names that sibling explicitly, so the differentiation is left to inference from the tool name.

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 phrase 'Optionally only one registrant' signals that registrant_account_id is a filter, implying usage, but there is no explicit when-to-use versus the account-scoped sibling or any exclusion/precondition guidance. Usage must be inferred from the name and the field list.

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