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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false. The description adds useful behavioral context beyond annotations: it explicitly says no commercial records or notifications are created, and it names the returned validation fields (missingFields, invalidFields, unsupportedFields), which is valuable since no output schema exists.

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?

Three short sentences, front-loaded with the core action and immediately followed by return details and side-effect exclusions. No wasted verbiage.

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?

The description covers return fields and side-effect exclusions, which is helpful for a read-only validation tool. But given the complex nested schema (9 parameters, deep requirements object) and no output schema, it lacks guidance on the requirements structure and how to interpret partial checks, leaving an agent under-informed for correct invocation.

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 only 33%, with many parameters (locale, contact, dates, deliveryType, deliveryTime) undocumented in both schema and description. The description mentions 'partial or complete rental need' implying optional inputs, but provides no parameter-level semantics to compensate for the low coverage.

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 ('Check') and resource ('rental need'), and clarifies it handles partial or complete needs. The final sentence ('No commercial records, no notifications') distinguishes it from commercial siblings like issue_rental_quote, though it does not name them.

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 usage by saying it returns missingFields with questions to ask the user, suggesting a validation step before quoting. However, it does not explicitly state when to use this tool versus siblings like issue_rental_quote or search_rental_offers, leaving alternatives implicit.

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