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

Annotations already declare readOnly, openWorld and idempotent, so the safety profile is covered. The description adds genuinely non-obvious behavioral context beyond that: a per-successful-call cost of 0.005 USDC via x402 on Base, and that errors are free — important for an agent deciding whether and how often to call.

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?

Two tight sentences with no filler; the capability and the returned fields come first and the pricing caveat is tacked on at the end. Slightly dense enumeration of gnr/bnr/fnr/snr, but nothing is wasted.

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?

With no output schema, the description usefully names the returned fields (coordinates, postcode, municipality, cadastre numbers, unit count) and covers the billing model. Pagination (page/size) is left entirely to the schema, which is acceptable for a read-only search tool.

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 the schema already documents q, page, size, postcode and municipality with formats and constraints. The description restates the search dimensions but adds no syntax or semantics beyond the schema, so the 3 baseline applies.

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 ('Search Norwegian street and cadastral addresses from Kartverket') and enumerates the query modes (text, municipality, postcode) and returned fields. It implicitly distinguishes itself from addresses_near by being a query/filter search rather than a proximity search, but never names that sibling explicitly.

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 through the listed search modes; the description never says when to prefer this over addresses_near or any other sibling, nor does it state exclusions. An agent can infer that text/postcode/municipality queries belong here, but must guess for geographic-radius cases.

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