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

Annotations already establish read-only, idempotent, non-destructive safety, so the bar is lower and the description clears it. It adds two genuinely useful behaviors not in the schema: results are ordered by listing tier then name, and the tool returns an empty array when no listed operators exist.

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 each deliver distinct value: action and scope, when to use it and the ranking expectation, and the empty-array edge case. There is no filler, and the most decision-relevant content is front-loaded.

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?

With a full output schema and safety annotations present, the description covers the key selection context, the ranking behavior, and the no-result scenario without redundant return-type explanation. The only minor gap is not naming sibling tools for alternate scenarios, but the slug-based versus location-based distinction is adequately implied.

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 coverage is 100% with rich descriptions for all four parameters (slugs, enum service values, limit with min/max/default), so the schema already documents semantics. The description merely rephrases 'optionally narrowed by service' and 'city slug plus state slug' without adding new detail, meeting but not exceeding the baseline.

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 a specific verb 'List' and names an exact resource ('valet operators serving a city slug plus state slug'), immediately distinguishing it from sibling search/nearest/operator-detail tools. The optional service narrowing and the ranking-by-tier detail make the tool's scope 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?

It gives an explicit 'Use this when an agent has a city already disambiguated' condition, which clearly routes an agent to this tool after city resolution rather than to city-search or nearest-location tools. It does not explicitly name the alternatives to use in other cases, but the disambiguation condition is strong contextual guidance.

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