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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, destructiveHint false, closed-world), so the description only needs to add data-scope context, and 'past guests and mutuals' does that. It says nothing about pagination behavior or what a result set looks like, which is a modest gap given the cursor parameter.

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 short sentence with no filler and the scope front-loaded. It reads as a fragment rather than a definition, which keeps it from a 5, but nothing should be cut.

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 four optional params, no output schema, and rich annotations, the definition is adequate but thin. It never addresses pagination via cursor or the exclusion behavior of not_on_event_id, both of which an agent would want framed at the description level.

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% and each of the four parameters carries its own documentation, including the non-obvious not_on_event_id. The description adds no meaning beyond the schema, so the baseline 3 applies.

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?

The description identifies the resource precisely: people you can invite, i.e. past guests plus mutuals. The scope addition ('and mutuals') goes beyond the tool name. It never says 'list' or gives a verb, and it does not distinguish itself from the sibling list_guests, so it falls short of a 5.

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?

There is no explicit when-to-use guidance and no named alternative. 'People you can invite' hints at a pre-invite discovery flow, but the agent gets no instruction on choosing this over list_guests or moving on to invite_guests.

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