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

The description adds valuable behavioral detail beyond the readOnlyHint/idempotentHint annotations: the 100-mile distance cap, nearest-first ranking, optional service narrowing, and the empty-array response if nothing qualifies. This fully informs the agent of operational expectations without contradiction.

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 a tight three-sentence structure that front-loads the core verb and scope, then adds the primary use case and empty-state behavior. Every sentence earns its place and no explicit guidance is lost in prose.

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 read-only, idempotent, non-destructive operation with a full input schema and an output schema, the description covers all necessary context: purpose, cap, ordering, optional filter, and failure response. It is sufficient for an agent to select and call the tool 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 100%, and each parameter already includes types, ranges, defaults, and enum options. The description adds minimal semantic value beyond 'coordinate' and 'optionally narrowed by service', so the baseline of 3 is appropriate since the schema carries the parameter documentation weight.

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 verb and resource: 'List nearest valet operators within a 100-mile cap of a coordinate, optionally narrowed by service.' It differentiates from city-based and operator lookup tools by emphasizing coordinates and fallback context, though it does not explicitly distinguish itself from the similarly named sibling valet_find_operators_near.

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 gives a concrete trigger scenario: 'Use this when a user is in a city with no listed operators and you need the closest available fallback ranked nearest-first.' This is useful, but it doesn't name alternatives or explicitly say when not to use the tool, leaving some inference about choosing between siblings.

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