MCP Carvana

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

With no annotations provided, the description carries full burden for behavioral disclosure. It states this provides an 'estimated' value, which implies approximation rather than guaranteed pricing, but doesn't mention whether this requires authentication, rate limits, data freshness, or what the output format looks like. For a valuation tool with zero annotation coverage, this leaves significant behavioral gaps.

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 single, well-structured sentence that efficiently communicates the tool's purpose and key parameters. Every word earns its place with no redundancy or wasted space, making it easy to parse quickly.

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?

Given the 8-parameter complexity and lack of both annotations and output schema, the description provides adequate purpose clarity but falls short on behavioral transparency and usage guidance. It's complete enough for basic understanding but insufficient for confident tool selection without additional context about how the estimation works or what the response contains.

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%, so the schema already documents all 8 parameters thoroughly. The description lists key parameters ('make, model, year, mileage, and condition') but doesn't add meaningful semantic context beyond what the schema provides. The baseline of 3 is appropriate when the schema does the heavy lifting.

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 specific action ('Get an estimated trade-in value') and resource ('your current vehicle on Carvana'), with explicit parameters listed. It distinguishes from siblings like 'get_financing_estimate' or 'get_market_insights' by focusing specifically on trade-in valuation rather than financing, market data, or vehicle details.

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 context through the parameter list ('based on make, model, year, mileage, and condition'), suggesting this is for valuation estimation. However, it doesn't explicitly state when to use this tool versus alternatives like 'get_market_insights' or 'search_by_budget', nor does it mention prerequisites or exclusions.

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