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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint. The description adds a useful list of returned fields, but it does not disclose any additional behavioral traits such as error handling, permission needs, or response shape. With annotations covering the safety profile, a 3 is appropriate.

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 leads with the verb and resource, then compactly lists the returned fields. There is no redundancy or filler; every word adds value.

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 simple lookup by ID, the description covers the return fields and the key identifier semantics. It lacks an explicit note about the overlapping sibling tool get_listing_details and potential edge cases, but given the low complexity and annotations, it is largely complete.

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 schema only defines car_id as an integer with no description. The description adds that it is the 'PegaRex id', giving domain meaning to the parameter. This helps compensate for the 0% schema coverage, but it does not provide format details or constraints beyond that.

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 action ('Fetch') and resource ('single listing by its PegaRex id') plus a detailed list of returned fields. It is specific but does not explicitly differentiate itself from the sibling tool get_listing_details, so it falls short of a 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?

No guidance is provided on when to use this tool versus alternatives like search_vehicles or get_listing_details. The description only states what it does, leaving the agent to infer usage from the name and general context.

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