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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=false, so the safety profile is covered. The description adds substantial behavioral context beyond that: it explains percentile semantics for low/typical/high, what take_home_usd means, that sample_size spans sold and past listings, that a narrowed range needs at least 5 matches and can differ in basis, and that available:false means insufficient data. Latency, permissions, and rate limits are not covered.

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?

It is front-loaded correctly with the 'Use when' trigger, and most sentences carry real information given the absence of an output schema. However, it is a dense run-on paragraph held together by semicolons and parentheticals, and the Marketplace/Craigslist/OfferUp reference is repeated, which hurts scanability.

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?

With no output schema, the description carries the full burden of documenting the response and does so nearly field by field: low/typical/high, take_home_usd, sample_size, narrowed_to, model_matches, basis, available, buyer_prices_usd, and added_to_buyer_price_usd. An agent can interpret the result without any other source.

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%, so both parameters are already documented. The description still adds meaning beyond the schema for model: it explains the narrowing is against listing titles, exposes the outcome via narrowed_to and model_matches, and states the 5-match threshold required for a narrowed range. Category itself gets no extra semantics.

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 resource and deliverable: comparable sale/list prices for a category, expressed as low/typical/high before delivery, with take-home figures. The framing around take-home vs buyer price implicitly separates it from pricing_quote_payout and pricing_quote_crosslist, though those siblings are never named. Purpose is clear but not explicitly contrasted with alternatives.

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?

It gives an explicit when-to-use trigger with concrete item types (fitness equipment, hot tubs, saunas, golf carts, furniture, appliances) and the cross-listing scenario (Facebook Marketplace, Craigslist, OfferUp). There is no when-not guidance and no sibling tool is named as an alternative, so the routing value is context-only.

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