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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely new context: 'Works signed out,' which tells the agent no auth is required, and warns that some categories can never be priced. It does not describe granularity of the coverage figures or latency.

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?

Three short sentences, front-loaded with the return content, then usage guidance, then the auth note. No filler; every clause carries information an agent needs.

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?

There is no output schema, so the description correctly takes on describing the return content (per-category data volume and unpriceable categories) and auth requirements. It stops short of specifying the metric's form (counts vs. percentages) or whether results are per-country granularity, which would matter for a coverage check.

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 description coverage is 0% and the description only alludes to a market scope ('per category for a market') without naming the country parameter, its six-value enum, or the US default. With one optional parameter entirely undocumented outside the raw schema, the description fails to compensate for the coverage gap.

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 resource and scope: sold-price data volume per category for a market, plus which categories can never be priced. The framing 'before building on the comps tools' cleanly separates it from siblings like get_sold_comps and get_sold_history, which return comps rather than coverage metadata.

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 says when to call it ('Check this before building on the comps tools') and why ('the honest answer about what we cannot do'). It gives clear context but no explicit when-not or named alternative for the case where coverage is already known.

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