MCP Carvana

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It mentions that the tool 'Returns a list of matching vehicles with basic details,' which gives some output context, but lacks critical details like whether this is a read-only operation, potential rate limits, authentication requirements, or pagination behavior. For a search tool with 14 parameters and no annotations, this is a significant gap.

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, efficient sentence that front-loads the core purpose and key parameters. It avoids redundancy and wastes no words, though it could be slightly more structured by separating usage guidelines or output details. Overall, it's appropriately sized for its function.

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 complexity (14 parameters, no output schema, no annotations), the description is minimally adequate. It covers the basic purpose and output format but lacks details on behavioral traits, usage context, and deeper parameter insights. Without annotations or output schema, it should do more to compensate, but it meets the minimum viable threshold for a search tool.

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?

The description lists example parameters ('make, model, year, price range, and other filters'), which adds minimal meaning beyond the input schema. Since schema description coverage is 100%, the schema already fully documents all 14 parameters with descriptions and enums. The description doesn't provide additional syntax, format details, or constraints, so it meets the baseline of 3 without adding significant value.

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's purpose: 'Search for vehicles on Carvana by make, model, year, price range, and other filters.' It specifies the verb (search), resource (vehicles on Carvana), and scope (multiple filters). However, it doesn't explicitly differentiate from sibling tools like 'search_by_budget' or 'get_vehicle_details,' which would be needed for a score of 5.

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 provides no guidance on when to use this tool versus alternatives. It doesn't mention sibling tools like 'search_by_budget' (which might focus on budget constraints) or 'get_vehicle_details' (which might retrieve specific vehicle info), leaving the agent with no context for tool selection. Usage is implied by the search functionality but not explicitly stated.

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