# io.usefulapi/numeral (remote · numeral.usefulapi.io)

Calculate sales tax & VAT, record transactions and refunds, manage products and customers.

- Trust score: 18/100 (low)
- Change this week: −50
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-08-03

## Components

- remote · `numeral.usefulapi.io`: 18/100 (this document), [markdown](https://verifymcp.io/servers/io-usefulapi-numeral/numeral.md), [page](https://verifymcp.io/servers/io-usefulapi-numeral/numeral)

## Channel facts

- Endpoint: `https://numeral.usefulapi.io/mcp`
- Transports: `streamable-http`
- Auth: `none`
- Version: `1.0.0`

## Trust breakdown

How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. Scores are 0–100 per category. Scoring method: https://verifymcp.io/docs/scoring (what has changed: https://verifymcp.io/docs/scoring/changelog)

Scored 2026-08-03.

- **Endpoint Security**: 46/100
  - The endpoint's TLS certificate is valid, in date, and uses a strong key.
  - Authorisation not fully verified: no authorisation is required to connect, but we couldn't read the tool list to see what that exposes.
  - HTTPS not yet verified: we couldn't determine whether a plaintext access path exists.
  - HSTS check failed: the Strict-Transport-Security header is absent.
  - DNSSEC check failed: this domain isn't protected by DNSSEC.
- **Transport & Reachability**: 0/100
  - Transport check failed: declared streamable-http, but the endpoint returned HTTP 429.
- **Schema Quality & AI Usability**: 0/100
  - Schema not yet verified: we couldn't read the endpoint's schema.
- **Stability & Change Management**: 0/100
  - Stability not yet verified: not enough scan history yet (needs a 30-day window).
- **Tool Coverage**: 0/100
  - Tool coverage not yet verified: we couldn't read the endpoint's tools.
- **Capabilities**: 0/100
  - Capabilities not yet verified: we couldn't read the endpoint's capabilities.

**Unverified: 4 categories.** Categories scored 0 because we could not verify them: authentication we do not have, an unreachable endpoint, or not enough scan history. We only credit what we can confirm.

## Install

### Claude

```bash
claude mcp add --transport http io-usefulapi-numeral https://numeral.usefulapi.io/mcp
```

### Codex

```toml
[mcp_servers.io-usefulapi-numeral]
url = "https://numeral.usefulapi.io/mcp"
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "io-usefulapi-numeral": {
      "type": "remote",
      "url": "https://numeral.usefulapi.io/mcp",
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add io-usefulapi-numeral --url https://numeral.usefulapi.io/mcp --transport streamable-http
```

### Hermes

```yaml
mcp_servers:
  io-usefulapi-numeral:
    url: "https://numeral.usefulapi.io/mcp"
```

### Other

```json
{
  "mcpServers": {
    "io-usefulapi-numeral": {
      "type": "http",
      "url": "https://numeral.usefulapi.io/mcp"
    }
  }
}
```

The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs.

## Changelog

Every change recorded for this component, newest first. Days that predate change tracking, or that we cannot explain, say so: "we were watching and nothing happened" and "we were not watching" are different claims.

### 2026-08-01 (score 18, −53)

- [security regression] Endpoint reachability: reachable → not serving MCP
- [security regression] Stability: 0.13 → unverified
- [security regression] Authorization: pass → unverified
- [security regression] Transport: pass → fail
- [functional regression] Capabilities: fail → unverified
- [functional regression] Tool coverage: 100 → unverified

### 2026-07-31 (score 71, +3)

- [functional] We updated how we score, so this day's move reflects our rubric, not a change to the server

### 2026-07-30 (score 68, −2)

- [functional] We updated how we score, so this day's move reflects our rubric, not a change to the server

### 2026-07-29 (score 70, +1)

No change was recorded against any check on this day. Stability & Change Management went from 3 to 7. That category is still filling its 30-day observation window: 1 days of observed history at the previous scan, 2 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-07-28 (score 69, +1)

- [functional improvement] Stability: unverified → 0.03

### 2026-07-27 (score 68, +56)

- [functional] We updated how we score, so this day's move reflects our rubric, not a change to the server

### 2026-07-26 (score 12)

First indexed and scored.

## MCP tools (11)

### `numeral_ping` (~41 tokens)

Ping (health check)

Health check — verifies the API key works and reports the environment (test/prod), api_version, and server timestamp. Numeral: GET /tax/ping.

### `numeral_calculate_tax` (~170 tokens)

Calculate tax

Calculate sales tax / VAT for an order — a STATELESS quote that persists nothing (record it later with numeral_create_transaction using the returned calculation id). Returns per-jurisdiction rates, total_tax_amount, and totals. Provide a customer address and one or more line items (each needs reference_product_id OR product_category). Amounts are in the currency's smallest unit (cents). Numeral: POST /tax/calculations.

Input parameters:

- `customer` (object, required): Customer details — address is required.
- `metadata` (object): Arbitrary string key/value metadata.
- `order_details` (object, required): Order details.
- `origin_address` (object): The address a product ships from. Optional on 2024-09-01; required on API version 2025-05-12+.

### `numeral_get_transaction` (~64 tokens)

Get transaction

Get a recorded transaction by its Numeral id (tr_...). Returns the transaction with its line items, currencies, and metadata. Numeral: GET /tax/transactions/{transaction_id}.

Input parameters:

- `transaction_id` (string, required): The Numeral transaction id (tr_...).

### `numeral_list_transaction_refunds` (~58 tokens)

List transaction refunds

List all refunds recorded against a transaction. Returns {refunds:[...]}. Numeral: GET /tax/transactions/{transaction_id}/refunds.

Input parameters:

- `transaction_id` (string, required): The Numeral transaction id (tr_...).

### `numeral_list_products` (~84 tokens)

List products

List your Numeral products (up to 50 per page), each with its reference id, name, and product_category. Use `cursor` (the last_product_id from a previous page) to paginate; has_more indicates more pages. Numeral: GET /tax/products.

Input parameters:

- `cursor` (string): Pagination cursor — pass the last_product_id from the previous page.

### `numeral_get_product` (~69 tokens)

Get product

Get a single product by its reference_product_id (your id). Returns the product's name, product_category, and timestamps. Numeral: GET /tax/products/{reference_product_id}.

Input parameters:

- `reference_product_id` (string, required): Your product id (the reference_product_id used when the product was created).

### `numeral_get_customer` (~124 tokens)

Get customer

Get a customer by id. By default `customer_id` is the Numeral id (cus_...); set id_type to "reference" to look up by your own reference_customer_id. Returns name, email, and tax-exempt status. Numeral: GET /tax/customers/{customer_id}.

Input parameters:

- `customer_id` (string, required): The customer id — a Numeral id (cus_...) by default, or your reference id when id_type="reference".
- `id_type` (string): Which id space `customer_id` is in (default: numeral).

### `numeral_create_transaction` (~137 tokens)

Create transaction

RECORDS a completed sale as a transaction — this WRITES a live tax/compliance record used for filings. Supply the `calculation_id` returned by numeral_calculate_tax and your `reference_order_id`. Numeral: POST /tax/transactions.

Input parameters:

- `calculation_id` (string, required): The calculation id returned by numeral_calculate_tax.
- `metadata` (object): Arbitrary string key/value metadata.
- `reference_order_id` (string, required): Your order id for this sale (used for record keeping / dedupe).
- `transaction_processed_at` (number): Unix timestamp (SECONDS) the sale was processed. Defaults to now if omitted.

### `numeral_create_refund` (~155 tokens)

Create refund

RECORDS a refund against a transaction — this WRITES a live tax/compliance record (adjusts tax owed). Use type="full" to refund the whole transaction, or type="partial" with line_items (each keyed by reference_product_id) for a partial refund. Numeral: POST /tax/refunds.

Input parameters:

- `line_items` (array): Required for type="partial": the line items to refund.
- `refund_processed_at` (number): Unix timestamp (SECONDS) the refund was made. Defaults to now if omitted.
- `transaction_id` (string, required): The transaction id (tr_...) to refund.
- `type` (string, required): "full" refunds the whole transaction; "partial" requires line_items.

### `numeral_create_product` (~112 tokens)

Create product

CREATES (or upserts) a product with its tax category — this WRITES to your Numeral product catalog, which drives future tax calculations. Numeral: POST /tax/products.

Input parameters:

- `product_category` (string, required): A tax category from Numeral's taxonomy, e.g. "GENERAL_MERCHANDISE", "SAAS_GENERAL".
- `reference_product_id` (string, required): Your product id (used to reference this product in calculations).
- `reference_product_name` (string, required): Human-readable product name.

### `numeral_create_customer` (~99 tokens)

Create customer

CREATES a customer record — this WRITES to your Numeral customer list (used for order tracking and tax exemptions). Numeral: POST /tax/customers.

Input parameters:

- `email` (string, required): Customer email (required).
- `is_tax_exempt` (boolean): Whether this customer is tax exempt.
- `name` (string): Customer name.
- `reference_customer_id` (string): Your own id for this customer (for reference-based lookups).

## Diagnostics

Captured diagnostic sections: TLS, DNSSEC, Authorisation, Transports. The full working is on the page: https://verifymcp.io/servers/io-usefulapi-numeral/numeral#diagnostics

## Score history

- 2026-08-03: 18
- 2026-08-02: 18
- 2026-08-01: 18
- 2026-07-31: 71
- 2026-07-30: 68
- 2026-07-29: 70
- 2026-07-28: 69
- 2026-07-27: 68
- 2026-07-26: 12

## Links

- Remote endpoint: https://numeral.usefulapi.io/mcp
- Repository: https://github.com/m190/usefulapi-mcp
- Changelog RSS feed: https://verifymcp.io/servers/io-usefulapi-numeral/numeral/changelog.xml
- Changelog JSON feed: https://verifymcp.io/servers/io-usefulapi-numeral/numeral/changelog.json
- HTML version of this page: https://verifymcp.io/servers/io-usefulapi-numeral/numeral