Look up location details for a supported zip or postal code by country and return geographic information for address validation, mapping, or regional workflows.
Look up location info for a zip/postal code.
| Name | Required | Description | Default |
|---|---|---|---|
| code | Yes | Zip or postal code | |
| country | No | Country code (default: us). Supports us, gb, au, ca, de, fr, etc. |
Changes observed during successful MCP inspections.
v0.1.11Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, so the safety profile needs no repeating. The description adds nothing beyond the one-line purpose: it does not say what 'location info' contains (city/state/lat-long?), whether lookups are case-insensitive, or what happens on an unknown code or unsupported country.
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 well-formed sentence with no filler, and the core action is front-loaded. It is arguably too terse rather than too verbose, but nothing in it 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 only two parameters and an output-schema-less response, the description should at minimum characterize what 'location info' returns and how country defaulting behaves. The schema covers the inputs, but the agent cannot predict the response shape or error behavior from this sentence.
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 both 'code' and 'country' (including the default 'us' and supported country list) are fully documented in the schema. The description adds no parameter-level meaning beyond that, making the baseline 3 appropriate.
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 ('look up') and resource ('location info for a zip/postal code'), which is clear on its own. However, the sibling list contains near-identical tools such as postcode_lookup, zip_by_city, and auspost_get_postcode, and the description never distinguishes this tool 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 description offers no when-to-use guidance, no exclusions, and no mention of the obvious alternative (zip_by_city reverses the direction; postcode_lookup overlaps directly). The agent must infer routing from the tool name alone.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.