estimate_landed_costCalculate total landed cost across proxy and shipping routes from listing price, weight or SKU, and destination country, then compare route costs.
出品価格・重量（またはsku_id）・仕向国から、代行×配送の経路別の総額目安と最安経路を返す。
| Name | Required | Description | Default |
|---|---|---|---|
| proxy | No | 代行名を指定して絞り込む（任意） | |
| sku_id | No | 正規SKU_ID（重量の参照に使用、任意） | |
| weight_g | No | 重量（g、sku_idが無い場合はこちらを指定） | |
| price_jpy | Yes | 出品価格（円、必須） | |
| dest_country | Yes | 仕向国（ISO2、例: US） |
Changes observed during successful MCP inspections.
v1.0.1Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations exist, so the description carries the full burden. It does disclose the computed outputs (route-by-route totals and the cheapest route), which implies a read-only calculation with no side effects, but it never states that explicitly, nor mentions cost model assumptions, currency of results, rate limits, or what happens when neither weight_g nor sku_id is supplied.
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?
A single dense sentence with zero filler, and the input-to-output relationship is front-loaded. The parenthetical placement of '(or sku_id)' inside a long clause slightly hurts parseability 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 does the necessary work of naming what is returned (per-route totals and the cheapest route), and the input schema fully covers the parameters. It leaves the return structure unspecified (field names, whether all routes or only the best are returned) and omits the neither-weight-nor-sku_id case, so it falls just short of complete.
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 all five parameters including the weight_g/sku_id fallback rule. The description reinforces the three primary inputs and the weight-or-sku_id alternative but adds no format, unit, or constraint details beyond what the schema 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 description states a specific verb and output set: it returns per-route proxy×shipping total cost estimates plus the cheapest route, driven by listing price, weight (or sku_id), and destination country. That is far more than a restatement of the name 'estimate_landed_cost' and makes the tool's function unambiguous. No sibling (resolve_listing, explain_product, discover, report_correction) overlaps, but the description does not explicitly differentiate itself from them.
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 '(or sku_id)' phrasing implies the alternative input path for weight, which is useful selection guidance. However, there is no statement of when this tool should be chosen over alternatives, no prerequisites, and no exclusions — usage is only indirectly implied by the listed inputs.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.