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

With no annotations present, the description carries the full burden and does so well: it discloses the paid cost ($0.01 USDC), that the server holds no wallet and never pays, that it returns HTTP 402 requirements (x402 on Base, MPP on Tempo), and the exact URL to retry. This is exactly the auth/payment behavior an agent needs before invoking.

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 core question and result contents before the payment mechanics. It is somewhat dense with parenthetical detail (x402 on Base, MPP on Tempo), but every sentence carries operational information.

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, and the description compensates by enumerating the components of the paid result plus the 402/retry flow. It does not describe the response's shape or units, but for an agent's selection and invocation decision nothing critical 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?

Schema coverage is 100%, so the baseline is 3, but the description adds meaning by tying the computation to LTI/LTV Central Bank checks and Help to Buy eligibility, which signals how income, deposit, mortgage and buyer_type are actually used. It still adds no format or unit guidance 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?

Opens with a concrete question and enumerates exactly what the paid result contains (stamp duty, Help to Buy estimate, LPT, legal/registration fees, LTI/LTV checks). This distinguishes it cleanly from siblings like paid_comps, paid_rent_check and paid_eu_house_prices, which cover different resources.

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?

The context of use is unambiguous ('cost to buy a home in Ireland') and the payment prerequisite is spelled out, including how to pay and retry. It never names a sibling alternative or states when-not to use it, so it falls short of a 5.

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