get_rulingAccess: API key required. One CBP CROSS ruling by number (for example N338012 or H313152), the same operation as GET /v1/rulings/{ruling_number}: its date, subject, the HTS codes it cites, the later and earlier rulings CBP lists against it, and, when extracted, the held HTS codes, holding and merchandise description from the ruling text. A ruling binds only the merchandise it was issued for.
| Name | Required | Description | Default |
|---|---|---|---|
| ruling_number | Yes |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden and does well: it discloses that an API key is required, enumerates what comes back (date, subject, cited HTS codes, later/earlier rulings), flags that some fields only appear 'when extracted', and warns that a ruling binds only the merchandise it was issued for. Missing only things like error behavior for unknown ruling numbers or pagination/size limits.
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 access requirement and the core operation, then the return detail, then the binding caveat — the ordering is sensible. It is a single dense sentence with long enumerations, slightly heavy for a one-parameter lookup.
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?
No output schema exists, so describing the returned fields is essential and the description does it thoroughly, plus auth and a domain caveat. For a simple single-argument lookup it is nearly complete; only error/not-found behavior is unaddressed.
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 0%, so the description must compensate, and it does by giving two concrete ruling-number examples (N338012, H313152) that convey the expected format beyond the bare regex pattern. It does not explain the letter prefix convention or the length bounds, keeping it short of a 5.
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 ('One CBP CROSS ruling by number') and anchors it to the equivalent REST endpoint, so the agent knows exactly what it retrieves. The examples (N338012, H313152) and the enumerated return fields make its scope unambiguous versus the sibling search_rulings.
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?
'One ... ruling by number' strongly implies lookup-by-identifier rather than keyword search, which routes the agent away from search_rulings. It never explicitly names search_rulings or states when not to use this tool, so it falls short of a full when/when-not statement.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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