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

Annotations already declare readOnly, idempotent, and non-destructive behavior. The description adds valuable context beyond this: the user finishes booking on DriveAway's site (no payment taken here), the tool returns a single booking_url, and it is Australia-only. This clarifies the external-redirect nature and geographic scope.

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 only two sentences, front-loaded with the core purpose, followed by essential usage notes and a constraint. Every sentence adds value with no redundancy.

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 tool's simplicity, the description covers purpose, usage, return value, payment handoff, and geographic scope. The schema documents all params, and annotations cover safety. Missing details like error handling or unsupported cities are minor for this use case.

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. The description adds minimal parameter context ('pickup city and dates') but does not elaborate on optional parameters like driver_age or passengers. The schema already provides sufficient detail for all parameters.

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 explicitly states the tool gets a DriveAway booking deep-link for campervan/motorhome hire given a pickup city and dates. It uses a specific verb ('Get') and resource ('DriveAway booking deep-link'), and distinguishes from sibling search tools by noting 'no search needed'.

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 provides clear usage context: use this once dates are chosen to provide a 'book now' link, and it explicitly says 'no search needed' to prevent misuse. It does not name a specific alternative tool, but the sibling list contains relevant search tools, making the guidance practical.

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