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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description earns credit by decoding result semantics beyond annotations: 'completed' is the only state that confirms provider success, and 'uncertain' must not trigger an automatic resend. It does not disclose whether records expire or whether polling is rate-limited.

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 sentences, no filler. The purpose is front-loaded and the state-interpretation caveat follows it immediately; every clause carries decision-relevant 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?

With no output schema, the description must carry the full burden of describing results, and it only covers two status values. It omits the existence of non-terminal states (e.g., pending/processing), what other fields the response returns, and where operationId is obtained, all of which an agent needs to poll correctly.

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 50% — operationId carries a rich schema description (high-entropy idempotency key, reuse only on exact retry) while accountId has none. The description contributes no parameter information at all, so it fails to compensate for the uncovered half as required at this coverage level; only the obvious, inferable nature of accountId keeps this above a 1.

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: 'Get the status of an accepted mail action.' No sibling among the 20 listed tools performs status polling, so it is trivially distinguishable from send_email, forward_email, and reply_to_email, which produce the actions it reports on. The agent knows exactly what this returns without opening the 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?

It supplies one operational rule — 'uncertain means do not repeat a send automatically' — which is a when-not for the calling agent, but it never says when to invoke the tool (immediately after send, or after a delay), nor that the required operationId originates from send_email/forward_email/reply_to_email. Usage is implied by 'accepted mail action' rather than stated.

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