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

Annotations only say the tool is a non-destructive, non-idempotent write. The description adds the crucial fact that no email is sent and the draft must be delivered by the caller, plus seat-cap accounting for pending invitations and the plan-limit error surface. A Guest's read-only scope is also disclosed, which no annotation conveys.

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?

Front-loads the action and the most dangerous misunderstanding (no email is sent) before role and email details. Dense but nearly every clause is load-bearing; the all-caps emphasis and repeated 'required' phrasing cost some tightness.

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 no output schema, the description correctly describes the return payload (link, subject, plaintext, HTML) and the error case (plan-limit message). Combined with the seat-cap and role semantics, an agent has everything needed to call this correctly and handle the result.

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 baseline is 3, but the description goes further by explaining that invitedEmail is the only address that can accept (and becomes the draft's To) and by characterizing what the Guest role actually grants. invitedName and personalNote are left to the schema, which is fine given full coverage.

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?

Opens with a specific verb and resource ('Create a workspace invitation') and immediately states what is returned (invite link plus a ready-to-send email draft with subject, plaintext, and HTML). This clearly separates it from list_invitations, revoke_invitation, and create_share_link.

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?

Gives concrete preconditions: administrator only, invitedEmail required and must be obtained from the user rather than guessed, and role constrained to four values. It also explains the Guest role's downstream consequence and the seat-cap behavior on Free plans. It doesn't name a sibling alternative (e.g., revoke_invitation to cancel), which keeps it below a 5.

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