# io.github.cmendezs/mcp-invoicenow-sg (pypi · mcp-invoicenow-sg)

MCP server for Singapore electronic invoicing (InvoiceNow)

- Trust score: 64/100 (medium)
- Change this week: −12
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-09-20

## Components

- pypi · `mcp-invoicenow-sg`: 64/100 (this document), [markdown](https://verifymcp.io/servers/cmendezs-mcp-invoicenow-sg/mcp-invoicenow-sg.md), [page](https://verifymcp.io/servers/cmendezs-mcp-invoicenow-sg/mcp-invoicenow-sg)

## Channel facts

- Registry: `pypi`
- Package: `mcp-invoicenow-sg`
- Version: `0.3.3`
- Transport: `stdio`

## Trust breakdown

How this component scores in each security and reliability category. Every signal is checked automatically from public evidence about the published package, including repeated runs of it in an isolated sandbox, 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 2026-09-20.

- **Supply Chain Security**: 50/100
  - Malware scan not yet available for this package.
  - No known CVEs affecting this package version or its production dependencies.
  - Runs hatchling.build at install time, a recognised native-build step with no shell scripting around it.
  - 2 of 29 dependencies flagged as unhealthy.
- **Provenance & Transparency**: 48/100
  - Source repository is publicly reachable at the declared URL.
  - Provenance check failed: no build-provenance attestation is published.
  - Clear OSI-approved license (Apache-2.0).
  - Actively maintained (last published 7 days ago).
  - Publishes a security disclosure policy (SECURITY.md).
- **Schema Quality & AI Usability**: 71/100
  - AI-judged instruction clarity (excellent).
  - Context-footprint check failed: tool/resource definitions use about 2479 tokens (~145/item across 17 items; 17 tools + 0 resources), over budget; trim descriptions and params.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 77/100
  - Stability observed for 23 of 30 days with no destabilising changes; credit accrues until the full window elapses.
- **Tool Coverage**: 96/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 86% of tool parameters carry a description.
  - Structured output schemas are declared (100% of tools); any adoption earns full credit.
- **Tool Safety**: 75/100
  - No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.
  - 0 of 1 tool(s) whose name or description implies an irreversible operation declare an MCP destructiveHint annotation; "peppol_send" implies "send" and declares no destructiveHint at all, which the MCP spec reads as destructive by default.
  - An AI judge read all 18 captured unit(s) of tool text and found none that tries to manipulate the model reading it.
- **Capabilities**: 100/100
  - Implements a current MCP spec version (2026-07-28).

## Install

### How do I install the io.github.cmendezs/mcp-invoicenow-sg server?

io.github.cmendezs/mcp-invoicenow-sg runs locally as a PyPI package, launched with uvx mcp-invoicenow-sg. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.

### Claude

```bash
claude mcp add cmendezs-mcp-invoicenow-sg -- uvx mcp-invoicenow-sg
```

### Cursor

```json
{
  "mcpServers": {
    "cmendezs-mcp-invoicenow-sg": {
      "command": "uvx",
      "args": [
        "mcp-invoicenow-sg"
      ]
    }
  }
}
```

### VS Code

```json
{
  "servers": {
    "cmendezs-mcp-invoicenow-sg": {
      "command": "uvx",
      "args": [
        "mcp-invoicenow-sg"
      ]
    }
  }
}
```

### Codex

```bash
codex mcp add cmendezs-mcp-invoicenow-sg -- uvx mcp-invoicenow-sg
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "cmendezs-mcp-invoicenow-sg": {
      "type": "local",
      "command": [
        "uvx",
        "mcp-invoicenow-sg"
      ],
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add cmendezs-mcp-invoicenow-sg --command uvx --arg mcp-invoicenow-sg
```

### Hermes

```yaml
mcp_servers:
  cmendezs-mcp-invoicenow-sg:
    command: "uvx"
    args: ["mcp-invoicenow-sg"]
```

### Netclaw

```json
{
  "McpServers": {
    "cmendezs-mcp-invoicenow-sg": {
      "Transport": "stdio",
      "Command": "uvx",
      "Arguments": [
        "mcp-invoicenow-sg"
      ]
    }
  }
}
```

### Vellum

```bash
assistant mcp add cmendezs-mcp-invoicenow-sg -t stdio -c uvx -a mcp-invoicenow-sg
```

### Other

```json
{
  "mcpServers": {
    "cmendezs-mcp-invoicenow-sg": {
      "command": "uvx",
      "args": [
        "mcp-invoicenow-sg"
      ]
    }
  }
}
```

## 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.

### 2026-09-19 (score 64, +1)

No change was recorded against any check on this day. Stability & Change Management went from 70 to 73. That category is still filling its 30-day observation window: 21 days of observed history at the previous scan, 22 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-18 (score 63, −15)

- [security regression] Malware scan: pass → unverified

### 2026-09-17 (score 78, +16)

- [security improvement] Malware scan: unverified → pass

### 2026-09-14 (score 62, −14)

- [security regression] Malware scan: pass → unverified

### 2026-09-12 (score 76, +1)

- [security regression] Tool safety: pass → unverified
- [security regression] Stability: 0.47 → unverified
- [functional regression] Capabilities: pass → unverified
- [functional regression] Tool coverage: 100 → unverified
- [functional] Package version: 0.3.2 → 0.3.3

### 2026-09-10 (score 75, +35)

- [security improvement] Injection markers: unverified → pass
- [functional improvement] Tool coverage: unverified → 100
- [functional improvement] Stability: unverified → 0.43
- [functional improvement] MCP protocol: unverified → pass
- [functional] Package version: 0.3.1 → 0.3.2

### 2026-09-09 (score 40, −34)

- [security regression] Stability: 0.37 → unverified
- [security regression] Tool safety: pass → unverified
- [functional regression] Capabilities: pass → unverified
- [functional regression] Tool coverage: 100 → unverified
- [functional] First check of Schema quality: unverified
- [functional] Package version: 0.3.1 → 0.3.2

### 2026-09-08 (score 74, +1)

No change was recorded against any check on this day. Stability & Change Management went from 33 to 37. That category is still filling its 30-day observation window: 10 days of observed history at the previous scan, 11 at this one. The score rises as the window fills, whether or not the server changes.

## MCP tools (17)

### `generate_invoice_sg` (~178 tokens)

Generate Invoice Sg

Build an SGInvoice from structured data and serialize it to UBL 2.1 XML.

\`invoice_data['profile']` (CustomizationID) and `invoice_data['business_process']`
(ProfileID) select PINT-SG or SG Peppol BIS Billing 3.0, and must be a
matched pair (TX2_Annex Annex B) — use get_profile_urn_sg to look up
both values together rather than setting them independently.
Returns the UBL XML (as a string) plus the customization_id/profile_id
that were applied. Does not validate against Schematron — call
validate_invoice_sg on the returned XML for that.

Input parameters:

- `invoice_data` (object, required): Invoice fields matching the SGInvoice schema (see get_profile_urn_sg for the profile URN to set).

### `validate_invoice_sg` (~259 tokens)

Validate Invoice Sg

Validate a UBL 2.1 XML invoice against IRAS's C5 acceptance-layer Schematron.

Runs IRAS's own C5 acceptance layer (checks documents that IRAS
itself would still reject, e.g. a missing buyer/seller UEN). The CEN
EN16931 base ruleset, PINT-SG's own jurisdiction overlay, and SG
Peppol BIS Billing 3.0 are NOT checked — see `scope` and the
\`EN16931-BASE-UNAVAILABLE` warning in the result, and
validators/schematron.py's module docstring for why (SGInvoice's GST
category codes have no sourced crosswalk to the UNCL5305 code list
the base ruleset requires; tracked as
[CORE-EN16931-BASE-SG-CROSSWALK-1]).

Requires the optional `xslt2` extra (`pip install
mcp-invoicenow-sg[xslt2]`) — the bundled stylesheet needs XSLT 2.0.
If missing, returns `level="unavailable"`.

Input parameters:

- `xml_content` (string, required): UBL 2.1 Invoice or CreditNote XML content to validate.

### `get_gst_category_codes_sg` (~76 tokens)

Get Gst Category Codes Sg

Return the IRAS GST category codes accepted on Singapore invoices.

Source: IRAS e-Tax Guide Annex E (supply/output-tax side only — the
purchase-side codes are out of scope for sent invoices). `rate` is
null for categories with no fixed rate ("NA" in the source table).

### `get_profile_urn_sg` (~204 tokens)

Get Profile Urn Sg

Return the CustomizationID (BT-24) and ProfileID (BT-23) for a Singapore profile.

CustomizationID comes from mcp_einvoicing_core.profile_registry
(registered at import time in models/invoice.py); ProfileID is a
shared Peppol process identifier, not per-country, so it is returned
from a local constant rather than the registry.

PINT_SG is the recommended profile for new senders — SG Peppol BIS
Billing 3.0 (BIS3) predates the PINT programme and is positioned as
legacy (per the package's own compliance reference, "Supported wire
formats and profile URNs" — user-supplied guidance, not independently verified
against an IRAS/IMDA notice). Not enforced as a hard default here;
callers choose explicitly.

Input parameters:

- `profile` (string, required): Profile key: 'PINT_SG' or 'BIS3'.

### `peppol_lookup_participant` (~120 tokens)

Peppol Lookup Participant

Check whether a business is registered on the Peppol network.

Performs a DNS-over-HTTPS U-NAPTR lookup followed by an SMP
service-group request to determine registration status and the list
of supported document type identifiers.

Input parameters:

- `environment` (string): "production" or "test".
- `identifier` (string, required): Peppol participant ID ("<scheme>:<value>") or a bare national identifier this server knows how to adapt (e.g. a VAT number, if a national identifier adapter is configured).

### `peppol_get_service_endpoint` (~153 tokens)

Peppol Get Service Endpoint

Fetch the AS4 endpoint for a Peppol participant's document type.

Resolves the SMP hostname via DNS, then fetches service metadata for
\*document_type_id*. If the SMP returns a redirect, the result's
\`redirect_url` is set and `endpoint_url` is None; callers must not
follow more than one redirect hop (SMP 1.4.0 §3.2).

Input parameters:

- `document_type_id` (string): Peppol document type identifier URN (default: BIS Billing 3.0 invoice).
- `environment` (string): "production" or "test".
- `identifier` (string, required): Peppol participant ID or adaptable national identifier.

### `resolve_peppol_dns` (~94 tokens)

Resolve Peppol Dns

Resolve the SMP hostname for a Peppol participant via DNS only.

Performs the raw U-NAPTR (SML) lookup without fetching the SMP
service group, useful for diagnosing whether a participant is
registered in the SML independently of SMP reachability.

Input parameters:

- `environment` (string): "production" or "test".
- `identifier` (string, required): Peppol participant ID or adaptable national identifier.

### `peppol_send` (~208 tokens)

Peppol Send

Send a UBL/CII invoice to a Peppol participant via AS4.

Looks up the recipient's AS4 endpoint (SMP), builds the ebMS3/AS4
envelope, and transmits it using the supplied signing credentials.

Input parameters:

- `certificate_path` (string, required): Path to the PEM-encoded signing certificate.
- `document_type_id` (string): Peppol document type identifier URN (default: BIS Billing 3.0 invoice).
- `environment` (string): "production" or "test".
- `invoice_xml_base64` (string, required): Base64-encoded UBL or CII invoice XML.
- `private_key_password` (string): Optional password for the private key.
- `private_key_path` (string, required): Path to the PEM-encoded private key.
- `recipient_identifier` (string, required): Peppol participant ID or adaptable national identifier of the receiver.
- `sender_id` (string, required): Peppol AP identifier of the sender.

### `list_participant_id_schemes` (~120 tokens)

List Participant Id Schemes

List Peppol participant identifier (ICD) schemes from the OpenPeppol eDEC code list.

Requires EINVOICING_PEPPOL_CODELIST_DIR to point at a local copy of
the eDEC "Participant Identifier Schemes" GeneriCode export (not
bundled with this package, no confirmed redistribution rights, see
\`mcp_einvoicing_core.peppol.codelists` module docstring).

Input parameters:

- `active_only` (boolean): When True (default), omit deprecated/removed entries.

### `list_document_type_ids` (~69 tokens)

List Document Type Ids

List Peppol document type identifiers from the OpenPeppol eDEC code list.

Requires EINVOICING_PEPPOL_CODELIST_DIR (see `list_participant_id_schemes`).

Input parameters:

- `active_only` (boolean): When True (default), omit deprecated/removed entries.

### `list_process_ids` (~67 tokens)

List Process Ids

List Peppol process identifiers from the OpenPeppol eDEC code list.

Requires EINVOICING_PEPPOL_CODELIST_DIR (see `list_participant_id_schemes`).

Input parameters:

- `active_only` (boolean): When True (default), omit deprecated/removed entries.

### `list_spis_use_case_ids` (~73 tokens)

List Spis Use Case Ids

List Peppol SPIS use case identifiers from the OpenPeppol eDEC code list.

Requires EINVOICING_PEPPOL_CODELIST_DIR (see `list_participant_id_schemes`).

Input parameters:

- `active_only` (boolean): When True (default), omit deprecated/removed entries.

### `check_document_type_id_in_codelist` (~95 tokens)

Check Document Type Id In Codelist

Check whether a (scheme, value) pair is a recognized Peppol document type identifier.

Requires EINVOICING_PEPPOL_CODELIST_DIR (see `list_participant_id_schemes`).
Searches all entries regardless of state, so a historical (deprecated
or removed) document type is still reported as found.

Input parameters:

- `scheme` (string, required)
- `value` (string, required)

### `check_process_id_in_codelist` (~68 tokens)

Check Process Id In Codelist

Check whether a (scheme, value) pair is a recognized Peppol process identifier.

Requires EINVOICING_PEPPOL_CODELIST_DIR (see `list_participant_id_schemes`).

Input parameters:

- `scheme` (string, required)
- `value` (string, required)

### `check_participant_id_scheme_in_codelist` (~74 tokens)

Check Participant Id Scheme In Codelist

Check whether a 4-digit ISO 6523 ICD code (e.g. "0208") is a recognized Peppol scheme.

Requires EINVOICING_PEPPOL_CODELIST_DIR (see `list_participant_id_schemes`).

Input parameters:

- `icd` (string, required)

### `get_peppol_codelist_version` (~32 tokens)

Get Peppol Codelist Version

Report the OpenPeppol eDEC code list release version(s) currently configured locally.

### `peppol_directory_search` (~188 tokens)

Peppol Directory Search

Search the Peppol Directory for registered participants.

Public, unauthenticated search (no relation to SMP lookup). At least
one of q/participant/name/country/doctype must be supplied.

Input parameters:

- `country`: Exact match on ISO 3166-2 country code.
- `doctype`: Exact match on a full document type identifier URN.
- `environment` (string): "production" or "test".
- `name`: Partial match on business entity name (min. 3 characters).
- `participant`: Exact match on a scheme-qualified participant ID (e.g. "iso6523-actorid-upis::0208:0123456789").
- `q`: General purpose query term, matched across all fields.
- `result_page_count` (integer): Results per page.
- `result_page_index` (integer): 0-based result page index.

## Diagnostics

Captured diagnostic sections: Provenance, Install scripts, Dependencies. The full working is on the page: https://verifymcp.io/servers/cmendezs-mcp-invoicenow-sg/mcp-invoicenow-sg#diagnostics

## Score history

- 2026-09-20: 64
- 2026-09-19: 64
- 2026-09-18: 63
- 2026-09-17: 78
- 2026-09-16: 62
- 2026-09-15: 62
- 2026-09-14: 62
- 2026-09-13: 76
- 2026-09-12: 76
- 2026-09-11: 75
- 2026-09-10: 75
- 2026-09-09: 40
- 2026-09-08: 74
- 2026-09-07: 73
- 2026-09-06: 58
- 2026-09-05: 72
- 2026-09-04: 72
- 2026-09-03: 71
- 2026-09-02: 71
- 2026-09-01: 70
- 2026-08-31: 69
- 2026-08-30: 49
- 2026-08-29: 64
- 2026-08-28: 64

## Common questions

### What is the io.github.cmendezs/mcp-invoicenow-sg server?

io.github.cmendezs/mcp-invoicenow-sg is listed in the public MCP registry as io.github.cmendezs/mcp-invoicenow-sg. MCP server for Singapore electronic invoicing (InvoiceNow). This page covers its PyPI package (mcp-invoicenow-sg).

### Is the io.github.cmendezs/mcp-invoicenow-sg server safe to use?

io.github.cmendezs/mcp-invoicenow-sg scores 64 out of 100 on VerifyMCP. We found no known CVEs affecting it as of 20 September 2026. 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 io.github.cmendezs/mcp-invoicenow-sg server expose?

io.github.cmendezs/mcp-invoicenow-sg exposes 17 tools: generate_invoice_sg, validate_invoice_sg, get_gst_category_codes_sg, get_profile_urn_sg, peppol_lookup_participant, and 12 more. Their descriptions and schemas cost roughly 2,078 tokens of context every time the server is loaded.

### Is the io.github.cmendezs/mcp-invoicenow-sg server still maintained?

io.github.cmendezs/mcp-invoicenow-sg is still listed as active in the MCP registry. We last reached this channel on 20 September 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.

### What licence is the io.github.cmendezs/mcp-invoicenow-sg server under?

io.github.cmendezs/mcp-invoicenow-sg declares the Apache-2.0 licence, which is OSI-approved. That covers the source only, and says nothing about the cost of any service it calls.

## Links

- PyPI project: https://pypi.org/project/mcp-invoicenow-sg/
- Socket report: https://socket.dev/pypi/package/mcp-invoicenow-sg
- Repository: https://github.com/cmendezs/mcp-invoicenow-sg
- Changelog RSS feed: https://verifymcp.io/servers/cmendezs-mcp-invoicenow-sg/mcp-invoicenow-sg.xml
- Changelog JSON feed: https://verifymcp.io/servers/cmendezs-mcp-invoicenow-sg/mcp-invoicenow-sg.json
- HTML version of this page: https://verifymcp.io/servers/cmendezs-mcp-invoicenow-sg/mcp-invoicenow-sg