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

Annotations declare destructiveHint/openWorldHint, but the description goes well beyond them: it enumerates the concrete side effects (deletes the Google Calendar event, emails the customer if an email exists, issues a full automatic refund when paid online) and explains the `refunded` outcome flag. This is exactly the side-effect disclosure a destructive tool needs.

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?

Three tight sentences, front-loaded with what the tool does, followed by side effects and the confirmation requirement. No filler or repetition of the schema.

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 and only annotations covering safety hints, the description supplies the missing behavioral detail: destruction scope, notification, automatic refund, and the return flag. An agent has everything needed to call it correctly and warn the user.

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 adds real meaning by explaining where `id` comes from (list_appointments) and that the pre-cancellation refund behavior is tied to the payment state. It does not elaborate on idempotencyKey/workspaceId, which the schema already documents.

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 (cancel) and resource (appointment) plus the scoping mechanism (by id from list_appointments). Clearly distinguished from sibling create_appointment and list_appointments without needing to open any 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?

Gives clear operational context: obtain the id from list_appointments, and 'Confirm with the user first' before invoking. No explicit when-not or alternative (e.g. reschedule) is offered, so it stops short of full routing guidance.

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