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

Annotations already declare it is a non-read-only, non-destructive, open-world write; the description adds genuinely new behavioral context on top: the owner-only authorization requirement and that re-inviting an existing address merely refreshes the invite link rather than erroring. It still does not say whether an email is dispatched or what happens to the previous link's validity window.

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 compact sentences with zero filler; the operation, the role options and the re-invite caveat are all front-loaded where an agent will see them first.

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 three-parameter mutation with full annotation coverage and no output schema, the description covers operation, authorization, defaults and the re-invite edge case. Minor gaps remain around notification behavior and the resulting invite state, but nothing blocks a correct call.

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 the schema already documents id, role (with enum) and email. The description's role list and default duplicate the enum/default already encoded in the schema, adding no syntax or format detail beyond it.

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 ('Invite someone to a site by email') plus the full role set, which makes it easy to separate from revoke_site_invite and list_site_members. It never names an alternative tool explicitly, so it stops short of the top-bar sibling differentiation.

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?

'Owner-only' gives the permission prerequisite for calling it, and '(default)' tells the agent what happens when role is omitted. It does not state when *not* to use it (e.g. use revoke_site_invite to undo) or what happens if the person is already a member.

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