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

Beyond the annotations (readOnlyHint=false, idempotentHint=true), the description discloses genuinely useful behavioral traits: $0.03/company pricing, 'unresolved lookups never charged', 'honest nulls' failure behavior, and per-field evidence + confidence output. No contradiction with annotations; in fact, the 'never charged' guarantee and paid nature align with readOnlyHint=false.

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 core transformation is front-loaded in the first sentence, and pricing is compactly stated. It loses a point for redundancy: 'GLEIF LEI / Japan NTA' and 'per-field evidence' each appear twice, so the description could be tightened without loss of 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?

With no output schema, the description compensates well by conveying output shape (verified profile with per-field evidence, confidence, honest nulls), billing behavior, and source registries. The payment flow is mostly delegated to the x_payment schema description. It is slightly incomplete on explicit differentiation from jp_company_profile and on output structure details, but for a complex paid enrichment tool it covers the essentials.

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. The description adds minor value by saying 'pass country_hint jp for Japanese companies,' slightly extending the schema's 'ISO country hint for registry lookups,' but this is marginal and largely redundant with the schema's own 'e.g. jp' example.

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?

The description states a specific transformation: company name/domain/URL to a verified profile, citing concrete registries (GLEIF LEI, Japan NTA). The 'Choose this when...' clause and registry-grounded framing effectively set it apart from siblings like jp_company_profile and verify_invoice without needing to open their schemas.

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?

'Choose this when you have a company NAME or DOMAIN and need a registry-grounded profile...' is explicit when-to-use guidance, and it gives a concrete parameter hint ('pass country_hint jp for Japanese companies'). It stops short of a full 5 because it names no explicit when-not-to-use cases or alternative sibling tools.

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