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

With annotations only covering safety flags (readOnly=false, destructive=false, openWorld=true), the description carries real behavioral weight: no charge, no room held, hotel confirms by email, guest pays at property, no payment step now or later, missing-field handling that may open a widget form, and the exception where some properties require payment at booking.

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?

Five sentences, front-loaded with the single most important fact (nothing is charged, no room held) before the input provenance and the payment exception. Slight redundancy between 'Nothing is charged and no room is held' and 'There is no payment step, now or later', which costs a point.

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?

Given 13 parameters, an output schema that already documents the confirmation code, and annotations that only cover safety, the description supplies the remaining context an agent needs: the non-committal nature of the call, fallback behavior for missing guest details, and the payment-at-booking exception.

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 description coverage is 100%, so the baseline is 3, but the description adds provenance the schema does not: which fields are sourced from get_hotel_detail versus from the guest, and that guestEmail cannot be changed after the request is sent. It does not explain totalAmount/currency sourcing in more depth than the schema already does.

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+resource ('Sends a booking request for a room at an OpenTravel partner hotel') and immediately scopes it as a non-binding request, which cleanly separates it from cancel_booking, check_booking_status and the get_hotel_detail family.

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?

Clearly states where the inputs come from ('Takes the room and rate from get_hotel_detail and the guest's name, phone number and email') and what happens when they are missing, which is strong usage context. It stops short of naming an explicit alternative or a when-not-to-use condition, so it is not a full 5.

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