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

Annotations already declare this a safe, idempotent, open-world read, so the description correctly spends its budget elsewhere: it discloses that prices are never converted and are in each city's local currency, that coverage dates differ per city because Inside Airbnb scrapes independently, and how sibling tools fail on uncovered cities. That is substantive context not present in the structured fields.

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?

Front-loaded with the resource and the return shape, and every sentence carries information (currency caveat, scrape-date caveat, sibling routing). It is a single dense paragraph with stacked parentheticals, though, and would scan faster as separated sentences.

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 carries the full burden of describing return values — and it does, field by field (display name, country, currency, listing count, median nightly price, data_as_of). Combined with the coverage caveat and sibling guidance, nothing an agent needs to call this correctly is missing.

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 tool takes zero parameters, so the baseline is 4 and there is nothing to document beyond that. The description's per-city return-field list is return-value information rather than parameter semantics, but it costs nothing here.

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 ('Every city this pack has short-term rental (Airbnb) data for') and names the upstream source (Inside Airbnb). It then enumerates exactly what each row contains, so an agent can distinguish it from str_city_summary and str_listings without opening either schema.

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?

Gives an explicit trigger ('Call this first if unsure whether a city is covered') and names the alternatives, describing how they behave differently ('str_city_summary and str_listings refuse an uncovered city by naming the covered set'). It even ranks the options ('this is the smaller way to check'), so the routing decision is unambiguous.

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