ng-postcode

Look up a Nigerian postcode

lookup_postcode

Read-onlyIdempotent

Verify whether a Nigerian NIPOST digital postcode is assigned to a building. Use this validation before relying on the postcode for address or building details.

Instructions

Confirm a postcode is assigned to a building. Free.

Address and building details are a paid lookup, listed as its own tool only when the server's NG_POSTCODE_MAX_LEVEL is 2 or more.

Input Schema

Name	Required	Description	Default
`level`	No	Always 1. Address and building details are a separate paid tool.
`postcode`	Yes	Code in any style, e.g. EK-01-A03-FK-01.

Output Schema

Name	Required	Description
`note`	No	Why the answer may be incomplete, such as a test key.
`valid`	Yes	Whether the code is assigned to a building.
`status`	No	valid, not_found, or invalid for a malformed code.
`postcode`	Yes
`verified`	No
`point_geometry`	No	Level 5, unstructured.
`building_use_status`	Yes	Level 3 and up, e.g. residential.
`other_building_info`	No	Level 4 and up, unstructured.
`recent_house_address`	Yes	Level 2 and up. Personal data.
`administrative_address`	Yes	Level 2 and up.

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedv0.4.6Oct 16, 2026

changedInput schema / properties / level / description

Previous value: -"Always 1. Higher levels are lookup_postcode_details."New value: +"Always 1. Address and building details are a separate paid tool."

Changed4 schema fields changedv0.4.5Oct 14, 2026

changedInput schema / properties / level / description

Previous value: -"1: validity only (free). 2: adds the administrative and recent house address. 3: adds building use. Levels 2+ consume NIPOST credits."New value: +"Always 1. Higher levels are lookup_postcode_details."

changedInput schema / properties / level / maximum
```
Previous value: -5New value: +1
```
addedInput schema / properties / postcode / maxLength
```
Added value: +64
```

addedOutput schema / properties / note

Added value: +{
+  "anyOf": [
+    {
+      "type": "string"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "description": "Why the answer may be incomplete, such as a test key.",
+  "title": "Note"
+}

First observedv0.2.4Oct 3, 2026

TDQS

B3.4/5.0

Behavior3/5

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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint, so the safety profile is covered. The description adds genuine non-annotation behavior: that this check is free and that a companion paid tool only appears when a server setting is 2+. It says nothing about how the check resolves, error behavior, or result semantics.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loads the core purpose in one short sentence, then adds pricing and server-gating context. It is compact and every sentence carries information, though the second paragraph is slightly awkward and reads as an aside.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists so return values need not be explained, and annotations cover the safety traits. What is missing is routing clarity inside a five-tool family of postcode helpers, plus any indication of what a negative confirmation means for the caller.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% and both parameters carry their own descriptions (level 'Always 1', postcode accepting any style). The description adds no syntax, format, or normalization guidance beyond that, so the baseline of 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description gives a specific verb and resource: 'Confirm a postcode is assigned to a building.' That is materially more precise than the title. It does not, however, distinguish itself from the closest sibling, validate_postcode, which an agent will reasonably confuse with this confirmation check.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

It notes the lookup is free and that address/building details live in a separate paid tool gated by NG_POSTCODE_MAX_LEVEL >= 2, which is conditional context for a sibling. It never states when to choose this over validate_postcode, autocomplete_postcode, or resolve_address, so selection is left to inference.

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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