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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered; the description adds the meaningful 'Owner-only' authorization requirement on top. It also hints at the returned content (roles, pending invite ids), which partly compensates for the absent output schema, though it omits pagination or result-count behavior.

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 short sentences, zero filler, with the core 'what' front-loaded and the access constraint last. Every clause earns its place.

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 simple one-param read with no output schema, the description covers scope, returned data shape at a high level, and the owner restriction. Pagination or ordering behavior is unstated, which is a minor gap but not needed to invoke the tool correctly.

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 the single 'id' parameter is documented as 'Site id.', so the schema already carries the semantics. The description only implies site scoping and adds no format or constraint detail beyond the schema, making the baseline 3 appropriate.

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 (list) and resource (site's members), and distinguishes its scope by adding pending invites, which separates it from sibling reads like list_sites or list_templates. An agent can tell it apart from invite_site_member/revoke_site_invite without opening a 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?

The 'Owner-only' clause gives a clear access precondition for when this call will succeed, which is real usage guidance. It doesn't explicitly name alternatives (e.g., invite_site_member to add members), but the read-vs-mutate split is clear from context.

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