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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and openWorldHint=false, so the safety profile is covered. The description adds real context beyond that: the figures come from live Roomly listings and are reported with the sample size they are based on, which tells the agent how much to trust a thin result. It stops short of saying what happens for a location with no listings or whether the location must be a known Roomly area.

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?

A single front-loaded sentence with a colon that enumerates the returned metrics, so the most useful information arrives first. Density is high with little waste, though the trailing 'with how many listings it is based on' is slightly clunky.

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 two-parameter read-only tool with full schema coverage, annotations, and no output schema, the description carries the right load by spelling out the return shape (median, range, sample size) that the missing output schema cannot. The only substantive gap is empty-result and location-matching behavior.

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 100% and the enum's 'Empty = all three' note already documents listing_type. The description only paraphrases that breakdown ('for a room, a whole apartment and a sublet') and echoes that location may be a city or area, without adding format, matching, or disambiguation rules beyond the schema.

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?

Names a precise resource (typical asking rent) and scope (a city or area on Roomly), and enumerates the exact metrics returned: median, usual range, and listing count, broken out by room, apartment, and sublet. It is clearly not a listing-retrieval tool, though it never names the siblings (search_listings, get_listing) it contrasts with.

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?

Usage is only implied: an agent can infer this is the pricing-overview tool rather than a listing lookup, since it returns aggregates 'from live listings'. There is no explicit when-to-use/when-not, no guidance on pairing with search_listings for the underlying listings, and no pointer to list_locations for valid location values.

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