pacs008-mcp

<!-- SPDX-License-Identifier: Apache-2.0 OR MIT -->

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

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<p align="center">
  <img src=".github/demo.gif" alt="pacs008-mcp Demo" width="100%" />
</p>

**A [Model Context Protocol][mcp] server that exposes the [`pacs008`][core]
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: v0.0.14**: 16 MCP tools over stdio, streamable HTTP or
> SSE, all backed by the `pacs008` library, for Python 3.10+. Adds `convert_mt103`, the legacy SWIFT
> MT103 → pacs.008 (MT→MX) migration path.

## Contents

- [Overview](#overview)
- [Install](#install)
- [Quick Start](#quick-start)
- [Transports](#transports)
- [Tools](#tools)
- [November 2026 structured-address cliff](#november-2026-structured-address-cliff)
- [Using the tools](#using-the-tools)
- [Development](#development)
- [Documentation](#documentation)
- [License](#license)
- [Contribution](#contribution)
- [Acknowledgements](#acknowledgements)

## Overview

The [Model Context Protocol][mcp] (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`][core] 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>

```mermaid
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.

```sh
python -m pip install pacs008-mcp
```

> **Note:** while the core `pacs008` library is not yet on PyPI, install it from
> source first:
>
> ```sh
> 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 default transport):

```sh
pacs008-mcp
```

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

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

## Transports

One command line, three transports:

| Command | Transport | Endpoint | Protocol revisions |
| :--- | :--- | :--- | :--- |
| `pacs008-mcp` | stdio | the client spawns the process | 2026-07-28, 2025-11-25 |
| `pacs008-mcp --transport streamable-http` | Streamable HTTP | `http://127.0.0.1:8000/mcp` | 2026-07-28 (stateless, `server/discover`) and 2025-11-25 (`initialize`, `Mcp-Session-Id`) on the same endpoint; responses stream as server-sent events, `GET` opens the server-to-client stream |
| `pacs008-mcp --transport sse` | HTTP+SSE (2024-11-05) | `http://127.0.0.1:8000/sse` and `/messages/` | for clients that still expect the older transport |

`--host` and `--port` change the bind address (defaults `127.0.0.1` and
`8000`). The HTTP transports carry no authentication of their own: bind
loopback, or put the server behind a gateway you trust before binding a
routable address. Every release is verified over streamable HTTP with
[passmcp](https://github.com/sebastienrousseau/passmcp) in both protocol
eras and over SSE with the MCP SDK client; see
[ADR 0001](https://github.com/sebastienrousseau/pacs008-mcp/blob/main/docs/adr/0001-three-transports-one-command-line.md).

```json
{
  "mcpServers": {
    "pacs008": { "url": "http://127.0.0.1:8000/mcp" }
  }
}
```

## Tools

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

- `list_message_types` — List the 20 supported ISO 20022 pacs message types
- `list_schemes` — List the registered scheme / usage-guideline profiles
- `get_scheme` — Inspect a scheme profile's rules
- `get_required_fields` — Required input fields for a message type
- `get_input_schema` — Full input JSON Schema for a message type
- `validate_records` — Validate flat records against a message type's schema
- `validate_scheme` — Validate records against a scheme's usage guidelines
- `generate_message` — Generate a validated pacs XML message
- `validate_xml` — Validate a raw XML string against the bundled XSD
- `parse_message` — Parse & classify an inbound ISO 20022 message
- `convert_mt103` — Convert a legacy SWIFT MT103 into pacs.008-ready records (MT→MX migration)
- `classify_address` — Classify a postal address as structured / hybrid / unstructured
- `validate_address` — Validate one postal address against an address policy
- `repair_address` — Upgrade legacy unstructured address lines toward hybrid/structured form
- `validate_addresses` — Batch-validate every party address across payment rows
- `verify_bic_online` — Check a BIC's format and look it up in a configured BIC directory (needs the `online` extra)

## November 2026 structured-address cliff

On **14 November 2026**, fully unstructured postal addresses are decommissioned
across SWIFT CBPR+, HVPS+, TARGET2 RTGS, CHAPS, Fedwire and Lynx — after that
date, any cross-border or high-value payment carrying an unstructured-only
postal address is **rejected at the rail**. The four address tools above wrap
the `pacs008` library's `standards.address` module so an agent can get ahead of
the deadline: `classify_address` shows where an address stands, `validate_address`
/ `validate_addresses` enforce a policy (defaulting to the cliff rule
`hybrid_or_structured`, which rejects unstructured addresses), and
`repair_address` runs country-aware heuristics (`GB`, `US`, `DE`, `FR`, `JP`,
plus a best-effort fallback) to lift legacy address lines into hybrid form.
The repair step is experimental — audit its output before submitting downstream.

## Using the tools

You can invoke the tools in-process — without a transport — straight through the
server instance. This mirrors what an agent receives over stdio. The runnable
version of this snippet lives in [`examples/mcp_tools.py`](https://github.com/sebastienrousseau/pacs008-mcp/blob/main/examples/mcp_tools.py).

```python
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:

```sh
python examples/mcp_tools.py
```

## Development

**pacs008-mcp** uses [Poetry](https://python-poetry.org/) and
[mise](https://mise.jdx.dev/).

```bash
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):

```bash
make check        # all gates (REQUIRED before commit)
make test         # pytest, 100% line+branch coverage
make lint         # ruff + black
make type-check   # mypy --strict
make doc-coverage # interrogate, 100% docstrings
make mutate       # mutmut over the tool handlers, gated
make docs         # Sphinx site, warnings are errors
```

---

## Documentation

- **Rendered docs:** [sebastienrousseau.github.io/pacs008-mcp](https://sebastienrousseau.github.io/pacs008-mcp/) — API reference, benchmarks, ADRs, changelog
- **Runnable example:** [`examples/mcp_tools.py`](https://github.com/sebastienrousseau/pacs008-mcp/blob/main/examples/mcp_tools.py)
- **Release history:** [CHANGELOG.md](https://github.com/sebastienrousseau/pacs008-mcp/blob/main/CHANGELOG.md)
- **Core library docs:** [pacs008.com](https://pacs008.com)
- **MCP specification:** [modelcontextprotocol.io](https://modelcontextprotocol.io)

---

## Related MCP Servers

Part of the **ISO 20022 MCP Suite** — open-source,