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

Annotations already declare destructiveHint=true and idempotentHint=false, and the description reinforces this with 'Not idempotent: each call creates a new request.' Beyond that it discloses substantial behavior the annotations cannot: the payment_url/deposit flow, instant_booking live-check semantics, the 'requested' vs 'confirmed' status lifecycle, error behavior when a room is just taken, and that Bookd never handles guest money. This is a rich disclosure well above the annotation bar.

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 purpose, then preconditions, then return values, then status semantics — a logical order. It is long, but nearly every sentence carries distinct operational information (payment, instant booking, error cases). Slightly dense, but not padded.

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?

No output schema exists, so the description must explain returns — and it does: booking_id, optional payment_url, and the meaning of 'requested' vs 'confirmed'. Combined with error-case and idempotency guidance, an agent has everything needed to invoke and interpret the call correctly.

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 60%, so the schema already documents room, message, creator_code, slug, and date formats. The description reinforces required inputs (room, dates, guests, name, email) but adds no syntax or format detail for the undocumented parameters (guest_phone, check-out semantics) beyond what the schema provides, so it lands at the baseline 3.

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 (send a booking request) and resource (a stay at a property for a room/unit and dates), and distinguishes itself from siblings by naming booking_status for follow-up and check_availability implicitly via the room parameter. An agent can tell it apart from cancel_booking or search_stays without opening schemas.

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?

Explicit precondition: 'Only call after the guest has confirmed the room, dates, guests, and given their name and email.' It also gives an explicit do-not: 'do not retry after a booking_id is returned (use booking_status),' naming the alternative tool. When-to-use and when-not-to-use are both covered.

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