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

Annotations already declare readOnlyHint and openWorldHint, but the description adds substantial context beyond them: the pricing model ($0.002 USDC per successful call via x402 on Base/Solana/Arc), that failed calls are not charged, the 15-per-page paging, and that a total match count is returned. This billing/auth detail is genuinely valuable and not captured by annotations.

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?

Dense but front-loaded: the resource and scope come first, followed by returned fields, paging, source, and pricing. Every sentence carries information, though the field enumeration and the pricing clause make it a fairly long single paragraph.

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 read-only, single-required-parameter search tool with an output schema, the description covers source, scope, returned fields, paging, and cost. Nothing an agent needs to invoke it correctly and anticipate charges 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 schema already documents query, status, and page. The description restates the 15-per-page paging and adds the returned field list, but does not add syntax or format detail beyond the schema. Baseline 3 is appropriate.

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 (New Zealand Companies Register search via the official NZ Companies Office) and enumerates the returned fields (name, number, NZBN, status, entity type, address, incorporation date). This clearly distinguishes it from the many other country/registry siblings such as b2b_brreg_norway_companies or b2b_ireland_cro_companies.

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 description implies usage context (keyword search against the NZ public register, with a status filter) but never explicitly states when to prefer this over a sibling registry or when it is the wrong choice. An agent can infer the domain from the name, but no explicit exclusions or alternatives are given.

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