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

The description clearly discloses a key behavioral trait not captured by annotations: the tool returns a URL instead of direct results, and the user must click 'Search' to see live pricing and availability. It also adds scope ('160+ rental companies') and explains what the user will see. This goes beyond the annotations (readOnly, openWorld, non-destructive) to give a transparent picture of the tool's indirect interaction model.

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 two sentences, front-loaded with the primary action, then the output and follow-up step. Every sentence earns its place with no repetition of schema details or fluff. It is concise yet sufficiently informative.

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 the schema covers all parameters, annotations cover safety, and the description explains the URL-return behavior and the need to click through, the description is quite complete. It might additionally mention that the tool does not provide results directly in the response, but that is already clearly stated. The only minor gap is lack of explicit guidance on when to use list_locations for context, which is more of a usage guidelines issue.

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 provides 100% coverage with clear descriptions for each parameter, including examples for city and date formats. The description only refers to 'trip details' generically without adding new parameter-specific meaning, so it meets the baseline for high schema coverage but does not exceed it.

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 clearly states the tool's function: 'Search campervan and motorhome rentals.' It then specifies the output format (a URL that pre-fills a search form) and distinguishes itself from the only sibling, list_locations, by focusing on rentals rather than location lookup. This makes the purpose specific and unambiguous.

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?

The description implies the tool should be used when searching for campervan/motorhome rentals, and it explains that live results require clicking 'Search' on the returned page. However, it does not explicitly mention when not to use it or contrast it with the sibling tool list_locations, so the usage guidance is implied rather than explicitly framed as an alternative.

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