compare_listings

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

No annotations are provided, so the description carries the transparency burden. It discloses that the tool 'pulls full details' and 'renders a comparison table,' which is informative. However, it does not mention whether authentication is required, rate limits, error behavior, or explicitly that it is read-only. This is partial disclosure, not comprehensive.

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 purpose and includes the output behavior. It contains no filler or redundant details, making it appropriately concise and well-structured.

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?

Without an output schema, the description partially describes the output as a 'comparison table' but does not specify its structure or what 'full details' entails. It does not mention error conditions, pagination, or auth needs. For a tool that compares up to 3 listings, this is moderately complete but leaves some ambiguity for an agent to make assumptions.

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 100%: both 'listings' (array with item descriptions) and 'includeImages' have descriptive text in the schema. The description adds little beyond the schema, only reiterating that comparison is by listingId or url. No additional parameter semantics are provided beyond what the schema already states.

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 states a specific action: 'Side-by-side comparison of 2–3 listings,' with explicit input methods (by listingId or url) and output ('renders a comparison table'). This clearly distinguishes it from siblings like get_listing_details (single listing) and search_cars (finding listings).

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 comparing multiple listings but does not explicitly state when to use it over single-listing tools (e.g., get_listing_details) or search tools. No alternatives or exclusions are mentioned, leaving the guidance implicit rather than explicit.

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