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

readOnlyHint=true already declares this a safe read. The description adds the underlying Neon endpoint and enumerates the returned data shape (accounts, tickets, attendees, amounts, payments), which is useful context, but says nothing about pagination behavior, result limits, or auth requirements even though pagination parameters exist.

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?

Two tight sentences: the action and its scope come first, the optional narrowing second, and the endpoint reference last. No filler or repetition.

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 compensates by naming the fields returned, and it identifies the primary and optional filters. It stops short of describing pagination semantics for a paginated list, but the essentials for correct invocation are present.

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 are already documented in the schema. The description only reinforces the registrant_account_id filter ('Optionally only one registrant'), adding no syntax or behavioral detail beyond the structured fields — the baseline 3 for full schema coverage.

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') plus the payload it covers (registrant account, tickets, attendees, amount, payments). It scopes to a single event and an optional registrant, which implicitly separates it from the account-scoped sibling neon_list_account_event_registrations, but never names that sibling explicitly.

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 description implies the usage context: fetch registrations for one event, optionally narrowed to a single registrant. It offers no explicit when-not guidance or pointer to the sibling tool for account-wide registrations, leaving the agent to infer the distinction.

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