Numeral MCP by usefulapi
REMOTE · NUMERAL.USEFULAPI.IO
Calculate sales tax & VAT, record transactions and refunds, manage products and customers.
Available components
Last scanned (3 hours ago)
Scores higher than 4% of remote servers
Reachable. Last reached 5 Nov 2026.
Category Finance and Payments
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. How we score → Why this is hard to score →
Endpoint Security46
- The endpoint's TLS certificate is valid, in date, and uses a strong key. View diagnostics → Pass
- Authorisation not yet verified: we couldn't confirm whether this endpoint requires it. View diagnostics → Unverified
- HTTPS enforcement could not be verified: the plaintext port redirected somewhere other than https, so enforcement is unproven. View diagnostics → Unverified
- HSTS check failed: the Strict-Transport-Security header is absent. See how to fix → View diagnostics → Fail
- DNSSEC check failed: this domain isn't protected by DNSSEC. See how to fix → View diagnostics → Fail
Transport & Reachability0
- Transport check failed: declared streamable-http, but the endpoint redirected instead of responding directly. See how to fix → View diagnostics → Fail
Schema Quality & AI Usability0
- Schema not yet verified: we couldn't read the endpoint's schema, or could read only part of its tool list.Unverified
Stability & Change Management0
- Stability not yet verified: not enough scan history yet (needs a 30-day window).Unverified
Tool Coverage0
- Tool coverage not yet verified: we couldn't read the endpoint's tools, or could read only part of the list.Unverified
Tool Safety0
- Tool safety not yet verified: we couldn't read the endpoint's tools, or could read only part of the list.Unverified
Capabilities0
- Capabilities not yet verified: we couldn't read the endpoint's capabilities.Unverified
Unverified: 5 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.
Checks we ran (4)
- TLS certificate
- HSTS header
- DNSSEC
- Transport
Checks we could not complete (7)
These are gaps on our side, not findings about this hosted endpoint. We only credit what we can confirm, so a category made up entirely of them scores 0.
- Authorization in Endpoint SecurityAuthorisation not yet verified: we couldn't confirm whether this endpoint requires it.
- HTTPS in Endpoint SecurityHTTPS enforcement could not be verified: the plaintext port redirected somewhere other than https, so enforcement is unproven.
- Schema quality in Schema Quality & AI Usability (scores 0 for this)Schema not yet verified: we couldn't read the endpoint's schema, or could read only part of its tool list.
- Stability in Stability & Change Management (scores 0 for this)Stability not yet verified: not enough scan history yet (needs a 30-day window).
- Tool coverage in Tool Coverage (scores 0 for this)Tool coverage not yet verified: we couldn't read the endpoint's tools, or could read only part of the list.
- Tool safety in Tool Safety (scores 0 for this)Tool safety not yet verified: we couldn't read the endpoint's tools, or could read only part of the list.
- Capabilities in Capabilities (scores 0 for this)Capabilities not yet verified: we couldn't read the endpoint's capabilities.
Does not apply to this hosted endpoint (2)
- Supply Chain SecurityScored on package channels only. This is a hosted endpoint, so there is nothing to install or inspect.
- Provenance & TransparencyScored on package channels only. This is a hosted endpoint, so there is nothing to install or inspect.
The score does not measure everything. What the score does not measure →
Every change we have recorded for this component, newest first. Security-relevant changes are always shown. ▲ marks a change for the better, ▼ a change for the worse; unmarked changes are neutral.
- 2 Nov 26 −62
- Endpoint reachability: reachable → not serving MCP ▼ security
- Stability: pass → unverified ▼ security
- Tool safety: pass → unverified ▼ security
- Authorization: pass → unverified ▼ security
- Schema quality: 100 → unverified ▼ functional
- Capabilities: pass → unverified ▼ functional
- Tool coverage: 100 → unverified ▼ functional
- 31 Oct 26 +3
- Authorization: partial → pass ▲ security
- MCP protocol: fail → pass ▲ functional
- New prompt “check_products_and_tax_categories_or_add_a_product” functional
- New prompt “get_a_tax_quote_for_an_order” functional
- New prompt “look_up_a_transaction_and_its_refunds” functional
- New prompt “look_up_or_add_a_customer” functional
- New prompt “record_a_completed_sale_as_a_transaction” functional
- New prompt “record_a_full_or_partial_refund” functional
- MCP protocol version: 2025-06-18 → 2025-11-25 functional
- Server version: 1.31.0 → 1.33.0 functional
- Server version: 1.30.0 → 1.31.0 functional
- Server version: 1.29.2 → 1.30.0 functional
- 30 Oct 26 0
- Server version: 1.29.1 → 1.29.2 functional
- Server version: 1.29.0 → 1.29.1 functional
- 29 Oct 26 0
- Server version: 1.28.0 → 1.29.0 functional
- Server version: 1.27.0 → 1.28.0 functional
- 28 Oct 26 0
- Server version: 1.25.0 → 1.27.0 functional
- 27 Oct 26 0
- Server version: 1.24.0 → 1.25.0 functional
- 25 Oct 26 0
- Server version: 1.23.0 → 1.24.0 functional
- Server version: 1.22.0 → 1.23.0 functional
- Server version: 1.21.3 → 1.22.0 functional
- Server version: 1.21.0 → 1.21.3 functional
- 24 Oct 26 0
- The server rewrote its instructions, which are the text every model session reads security
- Server version: 1.20.0 → 1.21.0 functional
- Server version: 1.19.0 → 1.20.0 functional
- Server version: 1.17.0 → 1.19.0 functional
Diagnostic detail from the automated scan of this channel: what the scanner observed at each step, so you can see exactly where a check passed or failed. It is informational only and never changes the trust score.
Captured 5 Nov 2026 · Probed https://numeral.usefulapi.io/mcp
TLS valid
Negotiated TLS 1.3 with TLS_AES_128_GCM_SHA256 .
| Subject | Issuer | Valid from | Valid until | Key | Signature | Serial |
|---|---|---|---|---|---|---|
| CN=usefulapi.io | CN=WE1,O=Google Trust Services,C=US | 13 Sept 2026 | 12 Dec 2026 | ECDSA 256 | ECDSA-SHA256 | d9be3287b0fde9630e825ba1f79bff3f |
| SANs: usefulapi.io, *.usefulapi.io | ||||||
| CN=WE1,O=Google Trust Services,C=US (CA) | CN=GTS Root R4,O=Google Trust Services LLC,C=US | 13 Dec 2023 | 20 Feb 2029 | ECDSA 256 | ECDSA-SHA384 | 7ff31977972c224a76155d13b6d685e3 |
| CN=GTS Root R4,O=Google Trust Services LLC,C=US (CA) | CN=GlobalSign Root CA,OU=Root CA,O=GlobalSign nv-sa,C=BE | 15 Nov 2023 | 28 Jan 2028 | ECDSA 384 | SHA256-RSA | 7fe530bf331343bedd821610493d8a1b |
Background: What to check on a remote MCP endpoint →
DNSSEC insecure
Validation of numeral.usefulapi.io. — Not signed
| Zone | DS | Keys | Algorithms | Outcome |
|---|---|---|---|---|
| . | Trust anchor | 20326, 38696 | 8, 8 | Verified |
| io. | DS published | 38690 | 8 | Verified |
| usefulapi.io. | No DS | Unsigned (proven) parent-signed NSEC/NSEC3 proves an unsigned delegation |
Authentication Inconclusive
We could not reach the endpoint well enough to judge its authorisation posture.
| Result | Inconclusive |
|---|---|
| HTTP status | 302 |
Background: How OAuth 2.1 works in the 2026 MCP spec →
Transports 2 probes
| Transport | URL | Outcome | Status | Location |
|---|---|---|---|---|
| streamable-http | https://numeral.usefulapi.io/mcp | Redirected | 302 | https://usefulapi.io/numeral/ |
| http (plaintext) | http://numeral.usefulapi.io/mcp | Inconclusive | 302 | http://numeral.usefulapi.io/mcp |
The tools this component advertises to a client, with an estimated token cost for each. Expand a tool to see its parameters and schema. The per-tool counts are indicative and are not scored directly; the schema's total context footprint is one signal in Schema Quality & AI Usability. A tool's description is untrusted text the model reads on every call, which is what makes this list a security surface and not just an inventory: how tool poisoning works →
numeral_calculate_tax Calculate tax ~170
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.
| Name | Type | Req | Description |
|---|---|---|---|
| customer | object | yes | Customer details — address is required. |
| metadata | object | – | Arbitrary string key/value metadata. |
| order_details | object | yes | Order details. |
| origin_address | object | – | The address a product ships from. Optional on 2024-09-01; required on API version 2025-05-12+. |
No output schema declared.
No examples provided.
numeral_create_customer Create customer ~99
CREATES a customer record — this WRITES to your Numeral customer list (used for order tracking and tax exemptions). Numeral: POST /tax/customers.
| Name | Type | Req | Description |
|---|---|---|---|
| string | yes | 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). |
No output schema declared.
No examples provided.
numeral_create_product Create product ~112
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.
| Name | Type | Req | Description |
|---|---|---|---|
| product_category | string | yes | A tax category from Numeral's taxonomy, e.g. "GENERAL_MERCHANDISE", "SAAS_GENERAL". |
| reference_product_id | string | yes | Your product id (used to reference this product in calculations). |
| reference_product_name | string | yes | Human-readable product name. |
No output schema declared.
No examples provided.
numeral_create_refund Create refund ~155
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.
| Name | Type | Req | Description |
|---|---|---|---|
| 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 | yes | The transaction id (tr_...) to refund. |
| type | string | yes | "full" refunds the whole transaction; "partial" requires line_items. |
No output schema declared.
No examples provided.
numeral_create_transaction Create transaction ~137
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.
| Name | Type | Req | Description |
|---|---|---|---|
| calculation_id | string | yes | The calculation id returned by numeral_calculate_tax. |
| metadata | object | – | Arbitrary string key/value metadata. |
| reference_order_id | string | yes | 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. |
No output schema declared.
No examples provided.
numeral_get_customer Get customer ~124
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}.
| Name | Type | Req | Description |
|---|---|---|---|
| customer_id | string | yes | 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). |
No output schema declared.
No examples provided.
numeral_get_product Get product ~69
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}.
| Name | Type | Req | Description |
|---|---|---|---|
| reference_product_id | string | yes | Your product id (the reference_product_id used when the product was created). |
No output schema declared.
No examples provided.
numeral_get_transaction Get transaction ~64
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}.
| Name | Type | Req | Description |
|---|---|---|---|
| transaction_id | string | yes | The Numeral transaction id (tr_...). |
No output schema declared.
No examples provided.
numeral_list_products List products ~84
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.
| Name | Type | Req | Description |
|---|---|---|---|
| cursor | string | – | Pagination cursor — pass the last_product_id from the previous page. |
No output schema declared.
No examples provided.
numeral_list_transaction_refunds List transaction refunds ~58
List all refunds recorded against a transaction. Returns {refunds:[...]}. Numeral: GET /tax/transactions/{transaction_id}/refunds.
| Name | Type | Req | Description |
|---|---|---|---|
| transaction_id | string | yes | The Numeral transaction id (tr_...). |
No output schema declared.
No examples provided.
numeral_ping Ping (health check) ~41
Health check — verifies the API key works and reports the environment (test/prod), api_version, and server timestamp. Numeral: GET /tax/ping.
Input schema present but exposes no named parameters.
No output schema declared.
No examples provided.
How do I install the Numeral MCP by usefulapi server?
Numeral MCP by usefulapi is a hosted endpoint at https://numeral.usefulapi.io/mcp, so there is nothing to install locally. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.
remote · numeral.usefulapi.io
claude mcp add --transport http io-usefulapi-numeral 'https://numeral.usefulapi.io/mcp'
What is the Numeral MCP by usefulapi server?
Numeral MCP by usefulapi is listed in the public MCP registry as io.usefulapi/numeral. Calculate sales tax & VAT, record transactions and refunds, manage products and customers. This page covers its hosted endpoint (https://numeral.usefulapi.io/mcp).
Is the Numeral MCP by usefulapi server safe to use?
Numeral MCP by usefulapi scores 18 out of 100 on VerifyMCP. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.
What tools does the Numeral MCP by usefulapi server expose?
Numeral MCP by usefulapi exposes 11 tools: numeral_ping, numeral_calculate_tax, numeral_get_transaction, numeral_list_transaction_refunds, numeral_list_products, and 6 more. Their descriptions and schemas cost roughly 1,113 tokens of context every time the server is loaded.
Does the Numeral MCP by usefulapi server require authentication?
Its publisher declares no required credentials for Numeral MCP by usefulapi. We have not been able to confirm that against the live endpoint, and a server can require authorisation without declaring it here.
Is the Numeral MCP by usefulapi server still maintained?
Numeral MCP by usefulapi is still listed as active in the MCP registry. We last reached this channel on 5 November 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.
What did VerifyMCP test on the Numeral MCP by usefulapi server?
VerifyMCP ran 4 checks on Numeral MCP by usefulapi, covering TLS certificate, HSTS header, DNSSEC and Transport. 7 items could not be completed, a gap on our side rather than a finding about Numeral MCP by usefulapi: Authorization, HTTPS, Schema quality, Stability and 3 more. 5 categories score 0 for that reason, because we only credit what we can confirm. Supply Chain Security and Provenance & Transparency do not apply to a hosted endpoint, so they were not tested. The score does not measure everything, and the scoring documentation lists what it leaves out.