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

Annotations already declare this is a non-read-only, non-idempotent, open-world mutation, so the description does not need to restate the safety profile. It adds genuine context beyond them: the invitation is delivered by email to an external recipient, and Free/Pro accounts are capped at 8 people, a hard constraint that determines whether the call succeeds.

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 with no filler, and the core action is front-loaded ahead of the constraint. The second sentence is telegraphic ('stop at 8 people') and does not say what happens when the cap is hit, so it is slightly under-explained rather than padded.

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 one-parameter mutation whose annotations cover safety, the description is minimally adequate: purpose plus one plan constraint. It omits who may invite (admin role), what happens on a duplicate invite, and what the caller gets back, with no output schema to fall back on.

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?

The single 'email' parameter has 0% schema description coverage, so the description carries the burden here. 'Invite a person' / 'Emails an invitation' implies one address per call rather than a batch, which is mild added meaning, but there is no guidance on format, validity, or behavior for an address that already has an account.

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 — it emails an invitation to join 'this Widely account' — which no sibling tool does, so it is distinguishable without opening the schema. It stops short of explicitly naming what it is not (e.g. it does not add a user directly or resend an existing invite).

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?

There is no explicit when-to-use or when-not-to-use guidance and no alternatives are named. The one implicit guideline is the plan cap ('Free and Pro stop at 8 people'), which tells the agent the call will be rejected on lower tiers once the team is full, but prerequisites such as the caller's admin permission are unstated.

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