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

Annotations already declare readOnlyHint=true and idempotentHint=true, so safety is covered. The description adds valuable behavioral context: results are deduped by VIN, sourced directly from dealer websites, include marketContext and freshness dates, and need no cross-checking. This exceeds annotation coverage 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 information-dense and well-structured, opening with the main action, providing an example, then detailing output fields and sourcing reliability. While slightly long, each clause earns its place 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?

For an 18-parameter search tool with an output schema, the description is quite complete. It addresses query flexibility, VIN behavior, output fields, sourcing, and dedup. It omits details like pagination or error handling, but these are minor given the limit parameter and typical expectations.

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 61%, and the description adds meaning to the query parameter by explaining plain-English parsing and exact-VIN lookup beyond the schema. However, it does not compensate for uncovered parameters like color, maxYear, minYear, or maxMileage, leaving some semantics unclear. The added value is moderate but incomplete.

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 searches live vehicle inventory across all dealerships, using a specific verb and resource. It differentiates from siblings by mentioning exact-VIN lookup and broad inventory searching, which contrasts with get_vehicle (single vehicle) and get_market_prices (market stats).

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 for searching vehicles (e.g., 'Search live cars for sale'), but it does not explicitly state when to prefer this over siblings like get_vehicle or get_market_prices. While it mentions VIN lookup, it doesn't contrast with get_vehicle. No explicit exclusions or alternative routing are given.

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