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

No annotations are provided, so the description carries the disclosure burden. It implies a read-only comparison and discloses the 2-5 item cardinality, but says nothing about behavior on unresolvable/duplicate slugs, ordering of results, or failure modes. Adequate for a simple read, but not rich.

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?

Two tight sentences: what is compared and on which fields comes first, the slug prerequisite second. Zero filler and nothing redundant with the schema.

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 one-parameter tool with no output schema, enumerating the compared fields effectively communicates what comes back, and the pre-resolution guidance covers the main failure mode. Minor gaps remain around result ordering and handling of invalid slugs.

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 0% and the single 'slugs' parameter has no schema description, so the description must compensate — and it does: it explains the parameter is a list of listing slugs, constrains it to 2-5 items, and tells the agent where to source valid values. Only the format/validation of individual slug strings is left unstated.

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?

States a specific verb and resource ('Compare 2-5 listings side by side') plus the exact comparison dimensions (pricing, access model, categories, heat, upvotes, rating). The multi-listing scope distinguishes it from get_listing, and the metric list makes the operation concrete rather than generic.

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?

Explicitly names the prerequisite path: slugs must first be obtained via search_listings or find_alternatives. That is real routing guidance against siblings. It stops short of an explicit when-not-to-use rule (e.g. 'use get_listing for a single listing'), so it is not a full 5.

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