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

Annotations already declare readOnlyHint=false, idempotentHint=false, and destructiveHint=false; the description adds the meaningful context that an actual email is dispatched, making the external side effect explicit. It stops short of noting that a repeat call sends a duplicate invitation or what permissions the caller needs.

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 clauses with the safety-critical directive front-loaded and no filler. The first clause restates itself slightly ('who to invite and with which role' / 'never choose for them'), but the redundancy is minor and reinforces the constraint.

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 schema coverage and annotations, the description covers the confirmation requirement and the email side effect. It omits what happens if the invitee is already a member or already invited, and what role the caller must hold to invite an admin — relevant for a single-shot, non-idempotent mutation.

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 coverage is 100%, so the schema already documents all three parameters and the baseline would be 3. However, the description says the invite role is 'admin or owner' while the schema enum only allows 'member' or 'admin' — an agent following the prose could submit an invalid value, so the description actively misleads rather than adding value.

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 ('Emails an invitation') plus the role scope, so the action is immediately clear. It does not distinguish itself from siblings like accept_invitation, revoke_invite, or list_invites, so an agent has no explicit routing cue.

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?

'Ask the user who to invite and with which role; never choose for them' is a strong directive about how to invoke, but it is not guidance on when to use this tool versus alternatives such as create_user_api or list_members. Usage is implied rather than framed against siblings.

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