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

Annotations already declare readOnlyHint=false, idempotentHint=false and destructiveHint=false, so the mutation profile is known. The description adds genuinely new context — no charge, email must match the order, slot must come from check_availability — but says nothing about what happens to the prior slot/booking or what is returned, so it doesn't reach rich disclosure.

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, and the cheap/free nature of the operation plus the required prerequisite are front-loaded where an agent will read them first.

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 3-required-param mutation with no output schema and no nested objects, the description covers auth, precondition, and cost. What's missing is what the call returns or confirms, and any disambiguation from the closely named sibling reschedule_booking.

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 67% and order_id has no schema description; the text clarifies that email must match the order the booking was created with, and reinforces that new_slot_id comes from check_availability. order_id is left completely unexplained in both places.

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 concrete verb+resource ("Move a booking to a different slot") and adds a salient constraint ("at no charge"). It does not differentiate itself from the sibling reschedule_booking, so an agent can't tell which reschedule to pick from the description alone.

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 prerequisite sequence ("Call check_availability first to get a valid new_slot_id") and an authentication condition (email must be the one used to create the order). It stops short of saying when to use this versus reschedule_booking or cancel_booking.

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