# validate_gstin

Validates the structure, format, and checksum of a GSTIN (Goods and Services Tax Identification Number), and extracts the State, PAN, Entity Type, and Checksum status.

Agent View of the PolicyLayer registry record for `validate_gstin`. HTML page: https://policylayer.com/tools/denispaul-india-business-mcp-server/validate-gstin

## Facts

- Tool: `validate_gstin`
- Server: India Business (`@denispaul/india-business-mcp-server`) — https://policylayer.com/tools/denispaul-india-business-mcp-server.md
- Install: `npx -y @denispaul/india-business-mcp-server`
- Homepage: https://www.npmjs.com/package/@denispaul/india-business-mcp-server
- Risk category: Read (Low risk)
- Registry record: grade A, identity unverified
- Server rate-limited: no
- Parameters: 1 (1 required)
- Recommended policy verdict: Allowed

## Parameters

| Parameter | Type | Required | Description |
| --- | --- | --- | --- |
| `gstin` | string | yes | The 15-character GSTIN (e.g., '27AAPFU0939F1ZV') |

Parameters from the server's own tool schema.

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "validate_gstin",
    "arguments": {
      "gstin": "<gstin>"
    }
  }
}
```

## Why validate_gstin is rated Low

This tool performs validation and extraction of information from a GSTIN number. It reads and parses an input string to verify its format and checksum, then returns extracted components (State, PAN, Entity Type, Checksum status). There are no side effects, no data modifications, no code execution, and no irreversible actions.

From the tool's own definition: "Tool 'validates the structure, format, and checksum of a GSTIN' and 'extracts' data; uses words like 'validates' and 'extracts' indicating data retrieval and validation only, with no modification, deletion, or execution of external operations."

## Use case

AI agents call validate_gstin to retrieve information from India Business without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

## Recommended policy (PolicyLayer)

Verdict: **Allowed**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches India Business:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "validate_gstin": {}
  }
}
```

## Other tools on India Business (5)

- `calculate_gst_tax` — Read — https://policylayer.com/tools/denispaul-india-business-mcp-server/calculate-gst-tax.md
- `check_pincode_serviceability` — Read — https://policylayer.com/tools/denispaul-india-business-mcp-server/check-pincode-serviceability.md
- `lookup_ifsc` — Read — https://policylayer.com/tools/denispaul-india-business-mcp-server/lookup-ifsc.md
- `lookup_pincode` — Read — https://policylayer.com/tools/denispaul-india-business-mcp-server/lookup-pincode.md
- `validate_pan` — Read — https://policylayer.com/tools/denispaul-india-business-mcp-server/validate-pan.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=denispaul-india-business-mcp-server · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/denispaul-india-business-mcp-server