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

Annotations only declare the write/open-world profile; the description adds substantial behavior beyond that: work items, price and status are preserved, length is retained unless end_time is passed, one-time notes are NOT carried over, confirmation defaults on, and the call reaches other people. These are exactly the mutation side-effects an agent 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?

Purpose is front-loaded in the first sentence, then consequences, then confirmation and auth requirements. Dense but every sentence conveys a distinct operational fact; slightly long but nothing is filler.

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 mutation tool with a fully covered schema and no output schema, the description supplies side-effects, confirmation behavior, and auth needs. It could state what the response returns, but the essential calling information is present.

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 schema documents each field, but the description adds the interplay that the schema does not: end_time changing the length, apply_to's this-vs-future semantics for recurring appointments, and the add_note remediation for dropped notes.

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 ('Move one appointment to a new date or time') and anchors it to the in-product Reschedule window. An agent can distinguish it from create_appointment, cancel_appointment, and get_appointment 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?

Gives clear usage context: it moves exactly one appointment, apply_to selects this-vs-future for recurring ones, and it requires confirming with the user before each call. It does not explicitly name alternative siblings to route away from, but the conditions for correct use are well covered.

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