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

Annotations establish write/non-destructive/open-world, and the description adds genuinely new behavioral facts on top: the side effect is an outbound email to the counterparty, it fires only once, and it is rate-limited to one per 24 hours. That cooldown is exactly the kind of operational detail annotations cannot express.

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 zero filler, and the usage condition is front-loaded ahead of the side-effect and rate-limit details. Every clause carries actionable 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 an output schema present, return values need not be described, and the description covers the trigger, the action, and the throttle. It omits edge cases such as behavior when the handshake is already complete or the counterparty cannot be reached, which would be the only remaining gap.

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?

Only one parameter, handshake_id, and schema coverage is 100%, with the schema already describing it as 'The Handshake the user is waiting on'. The description adds no format or validity guidance beyond what the schema states, so the baseline 3 applies.

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?

The description states a concrete action ('Emails them once') aimed at the counterparty of a Handshake, so the agent can tell this is an email-reminder tool rather than an in-app messaging tool like send_message. It is slightly indirect in that the verb 'nudge' carries the meaning only via the second clause, and it never names an alternative sibling to contrast with.

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 an explicit triggering condition: the user has completed their side of the Handshake and the counterparty has not. The 24-hour reuse constraint is stated. There is no explicit 'do not use when' or named alternative (e.g., send_message for other communication), 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.