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

Beyond the annotations, the description discloses major real-world behavior: no account is required, the car is held for 30 minutes, the trip confirms only after payment lands, the agent cannot self-serve payment, and change/cancel channels are provided. This is exactly the kind of operational context that annotations alone do not convey.

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?

The description is front-loaded with the core purpose and maintains a logical flow: booking, hold, payment, instruction to hand over the link, then post-booking contacts. It is somewhat dense, especially the second sentence, but every sentence earns its place given the complexity of the workflow.

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 19-parameter booking tool with no output schema, the description covers the critical workflow: real booking, hold window, external payment link, confirmation trigger, and post-booking support. It does not spell out the exact return payload shape or edge cases like an expired payment link, but it is complete enough for the agent to act effectively.

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?

The input schema already covers all 19 parameters with descriptions and enums, so the parameter-semantics burden is largely met by the schema itself. The tool description does not add specific parameter-level meaning beyond that, so a baseline 3 is appropriate.

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?

The description opens with "Place a real booking with no account," which is a specific verb plus resource and clearly distinguishes this tool from its siblings list_services and quote_trip. The subsequent details about the 30-minute hold and payment link reinforce that this is the actual booking action, not a quote or lookup.

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?

It explicitly instructs the agent to "Quote it first so you can tell them the price," implying quote_trip should be called before book_trip. It also warns that the agent cannot complete the payment and must hand the link to the person. It does not explicitly name alternatives or say when not to book, but the workflow guidance is clear enough.

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