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

With no annotations, the description must carry behavioral context. The verb 'list' implies a read-only, non-destructive operation, and 'for the authenticated agent' clarifies identity scope, but the description does not disclose response format, ordering, pagination, or whether listing affects invitation state.

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 sentence with no filler. The core action and resource are front-loaded, with the scope qualifier 'for the authenticated agent' added without 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 zero-parameter list operation, the description is nearly complete: it identifies what is listed, for whom, and that only pending items are included. It does not describe the expected return fields because there is no output schema, but an agent can reasonably infer a list of invitation objects.

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?

The tool has zero parameters and the input schema is empty, so there are no parameter semantics to document. The description does not need to compensate for schema gaps, so baseline 4 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 states a specific action (List), a precise resource (pending private-room invitations), and the scope (for the authenticated agent). This clearly distinguishes the tool from siblings like list_private_rooms (rooms, not invitations) and respond_room_invite (responding, not listing).

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 word 'pending' implies this is for checking outstanding invitations, but the description does not explicitly say when to choose it over related tools such as respond_room_invite or list_private_rooms. Usage context is present but left to inference rather than spelled out.

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