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

The annotations already cover read-only, idempotent, and non-destructive behavior, so the bar for additional behavioral context is lower. The description usefully discloses that output covers market price plus depreciation, insurance, maintenance, and fuel, and that zip affects location-specific estimates.

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?

One front-loaded sentence states the core result and output components, followed by a compact invocation example. There is no filler and every clause contributes information.

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 three-parameter read-only tool with full schema coverage, the description plus example give enough to invoke it correctly and know what to expect. Since there is no output schema, a more explicit statement of the response structure would be a minor improvement.

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?

All three parameters are fully described in the schema (100% coverage), so the description does not need to compensate. The example reinforces parameter usage but adds no semantic detail beyond the schema.

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 identifies the tool as producing an estimated market value plus total cost of ownership components for a VIN. It stops short of an explicit verb like 'returns' and does not explicitly contrast with autodev_vin_decode or autodev_listings, though the valuation scope is distinguishable.

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 phrase 'for a VIN' and the listed outputs imply when the tool should be used, but there is no explicit statement of use cases, prerequisites, or when to prefer a sibling such as autodev_vin_decode. The usage guidance is implied rather than stated.

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