GadgetHumans API Hub

vat_validate

Validate an EU or UK VAT number format and checksum and return the country and normalised form. Pure CPU, instant.

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": {
      "vat": "<vat>"
    },
    "name": "vat_validate"
  }
}

Input Schema

Name	Required	Description	Default
`vat`	Yes	VAT number to validate

Schema Changelog

Changes observed during successful MCP inspections.

AddedNov 8, 2026
RemovedNov 6, 2026

Changed2 schema fields changedNov 3, 2026

addedInput schema / properties / vat

Added value: +{
+  "description": "VAT number to validate",
+  "type": "string"
+}

addedInput schema / required
```
Added value: +[
+  "vat"
+]
```

AddedNov 2, 2026

TDQS

B3.3/5.0

Behavior3/5

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

With no annotations, the description carries the full burden; it usefully discloses that this is a pure CPU, instant, offline format+checksum check and that it returns the country and a normalised form. However, it does not say what happens for an invalid number (error vs. a valid=false result) or whether a country prefix is required in the input, which matters for correct invocation.

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?

Two short sentences, front-loaded with the action and scope, with zero filler; the latency note is terse and earns its place.

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?

There is no output schema, so the description is the only place return shape is described; it names country and normalised form but omits any validity flag and failure behavior. For a simple single-parameter validator that is close to adequate, but the missing failure semantics leaves a real gap.

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 coverage is 100% for the single 'vat' parameter, so the schema already documents it. The description adds only a hint that the input is a raw number containing a country prefix, and that normalisation occurs, which is mild added meaning beyond the schema.

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?

States a specific verb and resource (validate a VAT number), narrows scope to EU/UK, and says what it checks (format and checksum). It does not distinguish itself from the sibling tool 'eu_vat', which likely overlaps, so the reader cannot tell which to pick.

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

Usage Guidelines2/5

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

No when-to-use or when-not-to-use guidance is given, and the closely related sibling 'eu_vat' is never mentioned. The agent must guess whether this tool or 'eu_vat' is the right choice for a given VAT lookup.

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

All GadgetHumans API Hub tools Inspect

Try in Browser

One endpoint for every MCP toolRayrun runs every MCP server behind one URL and holds the credentials. Each call is decided per client, tool, and argument, then recorded.ray.runAd

Glama MCP Gateway

Add one secure layer between your agents and this server.