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

Annotations already declare readOnlyHint, destructiveHint=false and openWorldHint=false, so 'Read only' is redundant. What earns credit is the disclosure of conditional behavior (the invite email is only resolved 'when Keeploop can find it by the invite's UID') and the prompt-injection warning that titles/notes/locations are attacker-controlled data.

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 the identity of the resource and no filler; the safety caveat is last, which is the right place for it.

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?

An output schema exists so return-value shape needn't be restated, yet the description still summarizes the payload for routing purposes. Combined with annotations covering the safety profile and the added injection warning, nothing needed to call this tool correctly is missing.

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?

One parameter with 0% schema description coverage, so the description must carry the burden. It names event_ref as the lookup key and ties it conceptually to invite UIDs, but gives no format, example, or source for the ref, leaving agents to guess what a valid value looks like.

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 ('One event by event_ref') and goes on to enumerate the returned payload (attendees, their answers, linked invite email), which lets an agent distinguish it from list_events, find_invites and get_email without opening the schema.

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?

Clearly frames the tool as the single-event lookup (as opposed to the plural list_events) and explicitly hands off the invite email to the sibling get_email via mail_id. It stops short of stating when NOT to use it or when find_invites would be the better entry point.

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