pacs008-mcp: An MCP Server for ISO 20022 FI-to-FI Credit Transfers

A Model Context Protocol server that exposes the pacs008 ISO 20022 FI-to-FI Customer Credit Transfer library as tools for AI agents and assistants — discover message types and scheme profiles, validate records against the JSON Schema and against a rail's usage guidelines, generate validated XML, validate raw XML against the bundled XSD, and parse inbound messages, all from your favourite MCP client.

Latest release: v0.0.1 — nine MCP tools over stdio, all backed by the pacs008 library, for Python 3.10+.

Contents

• Overview

• Install

• Quick Start

• Tools

• Using the tools

• Development

• Licence

• Contribution

• Acknowledgements

Related MCP server: jPOS MCP Server

Overview

The Model Context Protocol (MCP) is an open standard that lets AI agents and assistants discover and call external tools in a uniform way. pacs008-mcp is an MCP server that turns the pacs008 library into a set of first-class agent tools, so an assistant can generate, validate, and parse ISO 20022 pacs.008 FI-to-FI Customer Credit Transfer XML messages — and the related pacs.002/.004 status and return messages — directly from a conversation.

Every tool is a thin, typed wrapper over the pacs008 library — the same package used by the CLI and REST API — so all interfaces behave identically. Tools return JSON-serialisable data; on a validation error they return an {"error": ...} payload rather than raising.

• Website: https://pacs008.com

• Source code: https://github.com/sebastienrousseau/pacs008-mcp

• Bug reports: https://github.com/sebastienrousseau/pacs008-mcp/issues

flowchart LR
    A["MCP client<br/>(Claude Desktop, IDE, agent)"] -->|stdio| B["pacs008-mcp"]
    B -->|delegates to| C["pacs008 library"]
    C -->|render + validate| D["ISO 20022 pacs XML"]

Install

pacs008-mcp runs on macOS, Linux, and Windows and requires Python 3.10+ and pip. It pulls in the core pacs008 library and the MCP SDK automatically.

python -m pip install pacs008-mcp

Note: while the core pacs008 library is not yet on PyPI, install it from source first:

python -m pip install "git+https://github.com/sebastienrousseau/pacs008.git"
python -m pip install pacs008-mcp

Quick Start

Launch the server over stdio (the FastMCP default transport):

pacs008-mcp

Register it with any MCP client (e.g. Claude Desktop) by adding it to the client's configuration:

{
  "mcpServers": {
    "pacs008": { "command": "pacs008-mcp" }
  }
}

Tools

All tools wrap the pacs008 library, so they behave identically to the CLI and REST API.

Using the tools

You can invoke the tools in-process — without a transport — straight through the FastMCP instance. This mirrors what an agent receives over stdio. The runnable version of this snippet lives in examples/mcp_tools.py.

import asyncio

from pacs008_mcp.server import server

record = [
    {
        "msg_id": "MSG001",
        "creation_date_time": "2026-01-15T10:30:00",
        "nb_of_txs": "1",
        "settlement_method": "CLRG",
        "interbank_settlement_date": "2026-01-15",
        "end_to_end_id": "E2E001",
        "interbank_settlement_amount": "1000.00",
        "interbank_settlement_currency": "EUR",
        "charge_bearer": "SHAR",
        "debtor_name": "Debtor Corp",
        "debtor_agent_bic": "DEUTDEFF",
        "creditor_agent_bic": "COBADEFF",
        "creditor_name": "Creditor Ltd",
    }
]


async def main() -> None:
    async def call(name, args):
        result = await server.call_tool(name, args)
        content = result[0] if isinstance(result, tuple) else result
        return content[0].text if content else ""

    print(await call("list_schemes", {}))
    xml = await call("generate_message",
                     {"message_type": "pacs.008.001.08", "records": record})
    print(xml[:46])  # -> <?xml version="1.0" encoding="UTF-8"?> ...


asyncio.run(main())

Run it directly:

python examples/mcp_tools.py

Development

pacs008-mcp uses Poetry and mise.

git clone https://github.com/sebastienrousseau/pacs008-mcp.git && cd pacs008-mcp
mise install
poetry install
poetry shell

This package depends on the core pacs008 library. Until it is on PyPI, install it from source first: pip install "git+https://github.com/sebastienrousseau/pacs008.git".

A Makefile orchestrates the quality gates (kept in lockstep with CI):

make check        # all gates (REQUIRED before commit)
make test         # pytest
make lint         # ruff + black
make type-check   # mypy --strict

MCP Registry

mcp-name: io.github.sebastienrousseau/pacs008-mcp

Licence

Licensed under the Apache Licence, Version 2.0. Any contribution submitted for inclusion shall be licensed as above, without additional terms.

Contribution

Contributions are welcome — see the contributing instructions. Thanks to all contributors.

Acknowledgements

Built on the pacs008 ISO 20022 FI-to-FI Customer Credit Transfer library and the Model Context Protocol Python SDK.