USPS Address Validation and Standardization MCP Server

validate_address

Validate and standardize US addresses via USPS API to receive corrected address data, delivery point validation, and standardized formatting.

Instructions

Validate and standardize a US address using USPS Address Validation API. Returns corrected address information, delivery point validation, and address standardization.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "streetAddress": "<streetAddress>",
      "city": "<city>",
      "state": "<state>",
      "zipCode": "<zipCode>"
    },
    "name": "validate_address"
  }
}

Input Schema

Name	Required	Description
`city`	Yes	City name (e.g., "New York", "Los Angeles")
`state`	Yes	Two-letter state code (e.g., "NY", "CA", "TX")
`zipCode`	Yes	ZIP code - 5 digits or ZIP+4 format (e.g., "12345", "12345-6789")
`urbanization`	No	Urbanization name (Puerto Rico addresses only)
`streetAddress`	Yes	Street address (e.g., "123 Main St", "456 Oak Avenue Apt 2B")

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Aug 10, 2026

TDQS

A3.8/5.0

Behavior3/5

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It reveals that the tool calls the USPS API and returns corrected address information, delivery point validation, and standardization. However, it does not disclose potential side effects (e.g., external API dependency, rate limits, authentication requirements) or behavior on invalid addresses. This is partial transparency.

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

Conciseness5/5

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

The description is a single sentence that effectively front-loads the tool's purpose and return value. Every phrase is informative: the API used, the action performed, and the outcomes. There is zero wasted content, making it highly concise and well-structured.

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

Completeness4/5

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

Given that there is no output schema and no annotations, the description adequately explains the return values (corrected address, delivery point validation, standardization) and the underlying service. It lacks explicit details about error handling or edge cases (e.g., invalid addresses), but the tool is relatively straightforward and the schema covers all inputs. The description is complete enough for most use cases.

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 all parameters already have detailed descriptions in the schema. The tool description does not add any additional meaning to the parameters beyond what the schema provides. The baseline score of 3 applies because the schema fully covers parameter semantics.

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

Purpose5/5

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

The description uses a specific verb ('validate and standardize') and identifies the resource ('US address') and the API used ('USPS Address Validation API'). It clearly states what the tool does and distinguishes it from any hypothetical alternatives by specifying the USPS-specific service. The purpose is unambiguous.

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?

The description implies usage for US address validation and mentions the return of corrected information, but it does not provide explicit guidance on when to use this tool vs alternatives, nor does it state when not to use it (e.g., for international addresses). No sibling tools are listed, so some guidance could be helpful but is not strictly required given the clear scope.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Deploy Server

Other Tools

validate_addressA