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

Annotations already declare destructiveHint=true, idempotentHint=false and openWorldHint=true, so the safety profile is known; the description adds genuinely useful detail by saying exactly what is destroyed (the old link stops working) and that expiry is extended by seven days. It stops short of stating permission requirements or that an email is dispatched to the invitee, so it is strong but not exhaustive.

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 zero filler. The core action is front-loaded and each clause (new link, extended window, old link dead) carries distinct information.

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 two-parameter mutation with no output schema and annotations that already flag destructive/non-idempotent behavior, the description covers action, effect and lifetime. Minor gaps remain: no mention of what happens if the invitation is no longer pending, and no pointer to the approval flow that the schema introduces.

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 baseline is 3, but the description adds a real constraint the schema lacks: the invitationId must reference a *pending* invitation, narrowing the valid value set. The two-step confirm gate is documented only in the schema, so no additional param credit there.

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 ('Email a pending invitation again') plus the concrete outcome (new link, seven more days, old link invalidated). The word 'pending' scopes the operation so an agent can separate it from invite_teammate (new invitation) and revoke_invitation (cancellation) 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 'pending invitation' precondition implies when the tool applies, but the description never names an alternative or an explicit when-not (e.g. use revoke_invitation to cancel, invite_teammate to create). The confirmation flow that governs invocation lives in the schema, not here, so guidance is inferred rather than stated.

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