# calculate_vat

Calculate VAT (Value Added Tax).

Agent View of the PolicyLayer registry record for `calculate_vat`. HTML page: https://policylayer.com/tools/io-tinyfn-tinyfn/calculate-vat

## Facts

- Tool: `calculate_vat`
- Server: TinyFn (`https://api.tinyfn.io/mcp/all/`) — https://policylayer.com/tools/io-tinyfn-tinyfn.md
- Homepage: https://github.com/tinyfn-io/tinyfn-mcp
- Risk category: Read (Low risk)
- Registry record: grade F, identity unverified
- Server auth posture: open
- Server rate-limited: no
- Parameters: 3 (1 required)
- Recommended policy verdict: Allowed

## Parameters

| Parameter | Type | Required | Description |
| --- | --- | --- | --- |
| `amount` | number | yes | Amount |
| `vat_rate` | number | no | VAT rate percentage |
| `inclusive` | boolean | no | Is amount VAT inclusive? |

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": "calculate_vat",
    "arguments": {
      "amount": 0
    }
  }
}
```

## Why calculate_vat is rated Low

This tool performs a read-only mathematical calculation (VAT computation) with no side effects, no financial transactions, no data modification, and no external operations. It is consistent with the server's stated purpose of deterministic math and conversion tools.

From the tool's own definition: "Calculate VAT (Value Added Tax) — performs a deterministic tax computation; server described as '500+ deterministic tools' for math/conversion"

## Use case

AI agents call calculate_vat to retrieve information from TinyFn 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 TinyFn:

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

## Other tools on TinyFn (571)

- `array_compact` — Destructive — https://policylayer.com/tools/io-tinyfn-tinyfn/array-compact.md
- `array_dedupe` — Destructive — https://policylayer.com/tools/io-tinyfn-tinyfn/array-dedupe.md
- `truncate_2` — Destructive — https://policylayer.com/tools/io-tinyfn-tinyfn/truncate-2.md
- `generate_hmac` — Execute — https://policylayer.com/tools/io-tinyfn-tinyfn/generate-hmac.md
- `random_float_2` — Execute — https://policylayer.com/tools/io-tinyfn-tinyfn/random-float-2.md
- `random_string_2` — Execute — https://policylayer.com/tools/io-tinyfn-tinyfn/random-string-2.md
- `random_weighted_choice` — Execute — https://policylayer.com/tools/io-tinyfn-tinyfn/random-weighted-choice.md
- `roll_dice` — Execute — https://policylayer.com/tools/io-tinyfn-tinyfn/roll-dice.md
- `null` — Other — https://policylayer.com/tools/io-tinyfn-tinyfn/null.md
- `absolute_value` — Read — https://policylayer.com/tools/io-tinyfn-tinyfn/absolute-value.md
- `acres_to_hectares` — Read — https://policylayer.com/tools/io-tinyfn-tinyfn/acres-to-hectares.md
- `add` — Read — https://policylayer.com/tools/io-tinyfn-tinyfn/add.md
- `adler32_checksum` — Read — https://policylayer.com/tools/io-tinyfn-tinyfn/adler32-checksum.md
- `analogous_colors` — Read — https://policylayer.com/tools/io-tinyfn-tinyfn/analogous-colors.md
- `analyze_password` — Read — https://policylayer.com/tools/io-tinyfn-tinyfn/analyze-password.md
- `array_difference` — Read — https://policylayer.com/tools/io-tinyfn-tinyfn/array-difference.md
- `array_first` — Read — https://policylayer.com/tools/io-tinyfn-tinyfn/array-first.md
- `array_frequency` — Read — https://policylayer.com/tools/io-tinyfn-tinyfn/array-frequency.md
- `array_interleave` — Read — https://policylayer.com/tools/io-tinyfn-tinyfn/array-interleave.md
- `array_intersection` — Read — https://policylayer.com/tools/io-tinyfn-tinyfn/array-intersection.md
- `array_last` — Read — https://policylayer.com/tools/io-tinyfn-tinyfn/array-last.md
- `array_nth` — Read — https://policylayer.com/tools/io-tinyfn-tinyfn/array-nth.md
- `array_partition` — Read — https://policylayer.com/tools/io-tinyfn-tinyfn/array-partition.md
- `array_repeat` — Read — https://policylayer.com/tools/io-tinyfn-tinyfn/array-repeat.md
- `array_reverse` — Read — https://policylayer.com/tools/io-tinyfn-tinyfn/array-reverse.md
- `array_rotate` — Read — https://policylayer.com/tools/io-tinyfn-tinyfn/array-rotate.md
- `array_slice` — Read — https://policylayer.com/tools/io-tinyfn-tinyfn/array-slice.md
- `array_symmetric_difference` — Read — https://policylayer.com/tools/io-tinyfn-tinyfn/array-symmetric-difference.md
- `array_union` — Read — https://policylayer.com/tools/io-tinyfn-tinyfn/array-union.md
- `array_unzip` — Read — https://policylayer.com/tools/io-tinyfn-tinyfn/array-unzip.md
- …and 541 more: https://policylayer.com/tools/io-tinyfn-tinyfn.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`

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