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

Annotations already establish readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds genuinely useful commercial behavior: $0.002 USDC per successful call via x402 on Base, Solana or Arc, with failed calls not charged, which an agent needs to know before invoking. It still says nothing about result volume, pagination, or coverage gaps in the source data.

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 dataset identity and geography are front-loaded, followed by the field list, filters, and pricing, so the important information arrives first. The enumerated field list is long but each item carries real selection value; the only minor drag is that pricing is appended rather than given its own sentence.

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 an output schema present, the description needn't explain return structure, and it covers identity, scope, filters, and payment terms adequately for a read-only open-world query. The remaining gaps (pagination or result caps, how missing months behave) are small but non-zero.

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%, with each parameter's format documented in the schema (2-letter flag codes, 7-digit IMO, month defaults). The description only restates which fields can be filtered and omits the year/month parameters entirely, so it adds little beyond what the schema already provides; baseline 3 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?

The opening clause names a specific verb and dataset ('Port state control detentions published by the Tokyo MOU'), scopes it by region (Asia-Pacific) and time (month), and then enumerates the returned fields. This clearly separates it from nearby siblings such as logistics_imo_vessel_dossier or logistics_sanctioned_vessel_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?

The description states the available filters (flag, IMO, port) and that records are scoped to a month, which implicitly tells an agent how to narrow results. However, it never says when to prefer this over a sibling lookup like the IMO vessel dossier, nor does it state any exclusions or prerequisites.

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