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

Annotations already declare destructiveHint=true and openWorldHint=true, so the safety profile is partly covered. The description adds materially: this is an outbound phone call the agent makes on the user's behalf, the booking record is updated only after the venue confirms, and the same waiting/idempotency rules as call_business apply. That is genuine behavioral context beyond the structured fields.

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?

Front-loaded with the core action, then constraints, then the deferral to call_business. Every sentence carries information. It is dense to the point of terseness, but nothing is wasted.

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 explained. The description covers action semantics, the reschedule prerequisite, confirmation behavior, and idempotency/waiting expectations, which is sufficient for an 8-parameter open-world call tool. Only minor gaps remain, such as explicit failure handling when the venue declines.

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. The description still adds value the schema cannot express: it ties action to its two values, states that the reschedule fields are conditionally required, and clarifies the merchant-local time basis. The conditional requirement is not encoded as an if/then in the schema, so this is real added meaning.

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 — phone the venue to cancel or reschedule a booking — and anchors it to a sibling artifact ('a confirmed booking from list_bookings'). An agent can distinguish it from list_bookings and call_business without opening 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 triggering context (modify a confirmed booking located via list_bookings) and the conditional dependency that reschedule requires new_date and/or new_time. It also defers waiting/idempotency behavior to call_business, an explicit sibling reference. It stops short of saying when not to use it (e.g., creating a new booking belongs elsewhere).

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