nearest_distribution_centersThe three closest AMSOIL distribution centers in the same country as a U.S. ZIP code or Canadian postal code, by straight-line distance. These are AMSOIL facilities, not A1 locations, and the nearest one may not fulfill an order.
| Name | Required | Description | Default |
|---|---|---|---|
| postal_code | Yes | U.S. ZIP code (for example 99156) or Canadian postal code (for example T5L 2T2). |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover read-only, idempotent, non-destructive, and closed-world semantics, so the safety profile is handled. The description adds real behavioral context the annotations cannot: distance is straight-line not driving, the facilities are AMSOIL (not A1), and proximity does not guarantee order fulfillment. It does not describe the shape of the returned records, but there is no output schema to lean on.
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?
Two sentences, zero waste. The core result ('three closest ... by straight-line distance') is front-loaded, and the two caveats follow compactly without redundancy.
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 single-parameter, read-only lookup with no output schema, the description covers what is returned and the non-obvious caveats that could mislead an agent (A1 vs AMSOIL, non-guaranteed fulfillment). Only the returned fields (address, contact) are left unstated, which is a minor gap.
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% and the single parameter is well documented with examples, so baseline is 3. The description modestly exceeds that by explaining the behavioral consequence of the input — the postal code's country determines which centers are eligible ('same country as') and that distance is measured straight-line.
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?
Names a precise resource and result set: the three closest AMSOIL distribution centers, ranked by straight-line distance, constrained to the same country as the input code. It explicitly distinguishes itself from 'A1 locations', which is a meaningful disambiguation. It does not contrast itself against sibling tools like contact_dealer, which would have pushed it to a 5.
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?
Usage is implied rather than stated: supply a ZIP/postal code to find nearby centers. The caveat 'the nearest one may not fulfill an order' is genuinely useful operational guidance, but no when-to-use/when-not-to-use framing or alternative (e.g., contact_dealer) is offered.
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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