# DATEV EXTF (npm · @seamless-engineering/datev-extf-mcp)

Validate and write DATEV-Format (EXTF) files locally, with findings in German and English.

- Trust score: 66/100 (medium)
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-09-26

## Components

- npm · `@seamless-engineering/datev-extf-mcp`: 66/100 (this document), [markdown](https://verifymcp.io/servers/engineering-seamless-datev-extf/seamless-engineering-datev-extf-mcp.md), [page](https://verifymcp.io/servers/engineering-seamless-datev-extf/seamless-engineering-datev-extf-mcp)

## Channel facts

- Registry: `npm`
- Package: `@seamless-engineering/datev-extf-mcp`
- Version: `0.1.0`
- 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 2026-09-26.

- **Supply Chain Security**: 100/100
  - No malware found by supply-chain analysis.
  - No known CVEs affecting this package version or its production dependencies.
  - No install/post-install scripts declared.
  - 0 of 4 dependencies flagged as unhealthy.
- **Provenance & Transparency**: 45/100
  - Source repository is publicly reachable at the declared URL.
  - Provenance check failed: no build-provenance attestation is published.
  - Clear OSI-approved license (MIT).
  - Actively maintained (last published 0 days ago).
  - Disclosure check failed: no security disclosure policy was found in the source repository.
- **Schema Quality & AI Usability**: 52/100
  - 20% of prompts and resources have a non-trivial description (not blank, and not just the item's name).
  - AI-judged instruction clarity (good).
  - Tool/resource definitions use about 661 tokens (~82/item across 8 items; 4 tools + 4 resources), lean.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 0/100
  - Stability not yet verified: not enough scan history yet (needs a 30-day window).
- **Tool Coverage**: 91/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 70% of tool parameters carry a description.
  - Structured output schemas are declared (100% of tools); any adoption earns full credit.
- **Tool Safety**: 100/100
  - No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.
  - We read all 4 captured tool definition(s), and no name or description among them implies an irreversible operation.
  - An AI judge read all 6 captured unit(s) of tool text and found none that tries to manipulate the model reading it.
- **Capabilities**: 100/100
  - Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.

**Unverified: 1 category.** A category scored 0 because we could not verify it: a data source with nothing on this package, evidence we could not reach, or a check we could not run. We only credit what we can confirm.

## Install

### How do I install the DATEV EXTF MCP server?

DATEV EXTF runs locally as an npm package, launched with npx -y @seamless-engineering/datev-extf-mcp. 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 engineering-seamless-datev-extf -- npx -y @seamless-engineering/datev-extf-mcp
```

### Cursor

```json
{
  "mcpServers": {
    "engineering-seamless-datev-extf": {
      "command": "npx",
      "args": [
        "-y",
        "@seamless-engineering/datev-extf-mcp"
      ]
    }
  }
}
```

### VS Code

```json
{
  "servers": {
    "engineering-seamless-datev-extf": {
      "command": "npx",
      "args": [
        "-y",
        "@seamless-engineering/datev-extf-mcp"
      ]
    }
  }
}
```

### Codex

```bash
codex mcp add engineering-seamless-datev-extf -- npx -y @seamless-engineering/datev-extf-mcp
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "engineering-seamless-datev-extf": {
      "type": "local",
      "command": [
        "npx",
        "-y",
        "@seamless-engineering/datev-extf-mcp"
      ],
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add engineering-seamless-datev-extf --command npx --arg -y --arg @seamless-engineering/datev-extf-mcp
```

### Hermes

```yaml
mcp_servers:
  engineering-seamless-datev-extf:
    command: "npx"
    args: ["-y", "@seamless-engineering/datev-extf-mcp"]
```

### Netclaw

```json
{
  "McpServers": {
    "engineering-seamless-datev-extf": {
      "Transport": "stdio",
      "Command": "npx",
      "Arguments": [
        "-y",
        "@seamless-engineering/datev-extf-mcp"
      ]
    }
  }
}
```

### Vellum

```bash
assistant mcp add engineering-seamless-datev-extf -t stdio -c npx -a -y @seamless-engineering/datev-extf-mcp
```

### Other

```json
{
  "mcpServers": {
    "engineering-seamless-datev-extf": {
      "command": "npx",
      "args": [
        "-y",
        "@seamless-engineering/datev-extf-mcp"
      ]
    }
  }
}
```

## 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.

### 2026-09-26 (score 66)

First indexed and scored.

## MCP tools (4)

### `validate_datev_extf` (~194 tokens)

Validate a DATEV EXTF file

Check a DATEV-Format (EXTF) CSV file, e.g. EXTF_Buchungsstapel.csv or a Debitoren/Kreditoren export, before importing it into DATEV or after DATEV rejected it. Returns every problem with line, field and a plain-language explanation in German or English: dot instead of comma in amounts, missing leading zeros in Belegdatum, BU-Schlüssel on automatic accounts, account length, encoding, header errors and more. Pass a file path (preferred, the encoding is checked too) or the file content.

Input parameters:

- `content` (string): The file content as text, if there's no file. The encoding can't be checked this way.
- `lang` (string): Language of the messages: de (default) or en.
- `path` (string): Path to the CSV file on this machine. Relative paths resolve against the server's working directory.

Output parameters:

- `category` (string): buchungsstapel, debkred or other
- `countsByCode` (object)
- `disclaimer` (string)
- `encoding` (string)
- `errors` (number)
- `findings` (array)
- `header` (object)
- `rows` (number)
- `truncated` (boolean)
- `warnings` (number)

### `explain_datev_finding` (~89 tokens)

Explain a DATEV EXTF finding code

Explain what a validate_datev_extf finding code (e.g. amount-dot, bu-automatic, date-leading-zero) means and how to fix it. Placeholders like {value} or {max} stand for values from the specific finding.

Input parameters:

- `code` (string, required): The finding code.
- `lang` (string): Language of the messages: de (default) or en.

Output parameters:

- `code` (string)
- `disclaimer` (string)
- `explanation` (string)

### `write_buchungsstapel` (~173 tokens)

Write a DATEV Buchungsstapel

Create a DATEV-Format Buchungsstapel (EXTF, Formatversion 13) from booking rows, ready for import into DATEV Rechnungswesen or DATEV Unternehmen online. The result is checked with the validator before it's returned. With outputPath the file is written as Windows-1252, the encoding DATEV expects; without it the CSV text is returned. The tool formats bookings, it doesn't choose accounts or tax keys: take those from the user or their tax advisor.

Input parameters:

- `header` (object, required)
- `lang` (string): Language of the messages: de (default) or en.
- `outputPath` (string): Where to write the file, e.g. EXTF_Buchungsstapel.csv. Existing files are overwritten.
- `rows` (array, required)

Output parameters:

- `changed` (array): Belegfeld 1 values the writer had to clean, and texts with characters Windows-1252 can't hold
- `csv` (string)
- `path` (string)
- `report` (object)
- `rows` (number)

### `list_datev_columns` (~80 tokens)

List DATEV EXTF columns

List the columns (line 2) of a DATEV Buchungsstapel (Formatversion 13, 125 columns) or Debitoren/Kreditoren file (254 columns), numbered by position. Use it to map export fields to DATEV columns or to find a column named in a finding.

Input parameters:

- `format` (string, required)

Output parameters:

- `asOf` (string)
- `columns` (array)
- `format` (string)

## Diagnostics

Captured diagnostic sections: Provenance, Dependencies. The full working is on the page: https://verifymcp.io/servers/engineering-seamless-datev-extf/seamless-engineering-datev-extf-mcp#diagnostics

## Score history

- 2026-09-26: 66

## Common questions

### What is the DATEV EXTF MCP server?

DATEV EXTF is an MCP server listed in the public MCP registry as engineering.seamless/datev-extf. Validate and write DATEV-Format (EXTF) files locally, with findings in German and English. This page covers its npm package (@seamless-engineering/datev-extf-mcp).

### Is the DATEV EXTF MCP server safe to use?

DATEV EXTF scores 66 out of 100 on VerifyMCP. We found no known CVEs affecting it as of 26 September 2026. It declares no install or post-install scripts. 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 DATEV EXTF MCP server expose?

DATEV EXTF exposes 4 tools: validate_datev_extf, explain_datev_finding, write_buchungsstapel, list_datev_columns. Their descriptions and schemas cost roughly 536 tokens of context every time the server is loaded.

### Is the DATEV EXTF MCP server still maintained?

DATEV EXTF is still listed as active in the MCP registry. We last reached this channel on 26 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 DATEV EXTF MCP server under?

DATEV EXTF declares the MIT licence, which is OSI-approved. That covers the source only, and says nothing about the cost of any service it calls.

## Links

- npm package: https://www.npmjs.com/package/@seamless-engineering/datev-extf-mcp
- Socket report: https://socket.dev/npm/package/@seamless-engineering/datev-extf-mcp
- Repository: https://github.com/seamless-engineering/datev-extf-mcp
- Website: https://seamless.engineering/tools/datev-extf-validator/
- Changelog RSS feed: https://verifymcp.io/servers/engineering-seamless-datev-extf/seamless-engineering-datev-extf-mcp.xml
- Changelog JSON feed: https://verifymcp.io/servers/engineering-seamless-datev-extf/seamless-engineering-datev-extf-mcp.json
- HTML version of this page: https://verifymcp.io/servers/engineering-seamless-datev-extf/seamless-engineering-datev-extf-mcp