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

With no annotations, the description carries the full burden and does so unusually well: it discloses pricing ($0.05 USDC), the exact payment protocols (x402 on Base, MPP on Tempo), that the server holds no wallet and never pays, that it returns HTTP 402 requirements plus the target URL, and that the caller must retry after paying.

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?

The first sentence front-loads the purpose and the rest is dense but every clause carries needed information (source, metrics, payment flow, URL). Slightly crammed into one long sentence, but no filler.

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 paid tool with no annotations and no output schema, the description covers what is returned, the source, the payment mechanics, and the retry workflow. An agent has everything needed to attempt the call and handle the 402 response.

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%, so county, segment, and quarters are already documented in the schema. The description reinforces segment semantics (new vs second-hand) and the trailing-12-month framing of quarters, but adds no syntax or defaults 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?

States a specific verb+resource (Irish residential sale-price comps by county) and enumerates exactly what is returned: median/p25/p75 per quarter and trailing 12 months, new vs second-hand, sourced from the PSRA Property Price Register. This is clearly distinguishable from the rent-oriented siblings (county_rent, paid_rent_check).

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 clear context for when and how to use it (paid endpoint, pay with your own x402/MPP client and retry the URL) and an exclusion ('Not a valuation'). It does not explicitly contrast with county_rent/paid_rent_check, so the routing between siblings is only implied.

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