Scribo

io.github.causa-prima-aiPublished by GitHub account causa-prima-aiv1.0.0Updated Oct 25, 2026

EN 16931-compliant e-invoices: XRechnung, ZUGFeRD, Factur-X, Peppol BIS, Facturae or US PDF. Free.

VerifiedStreamable HTTPWeb executableFinanceBusiness & Commerce

Overview

AI-generated overview

Scribo is a hosted MCP endpoint that lets an assistant draft, generate and re-download compliant e-invoices from plain-language descriptions.

What you can do
Create invoices from sender, recipient and line-item details, returning a download link; German senders get EN 16931 output (XRechnung or ZUGFeRD), US senders a plain PDF, and other jurisdictions are rejected as unsupported. Verify ownership of the sender email with a 6-digit code when the first invoice from that address requires it. Fetch a previously generated invoice by its ID with a freshly signed download link. List the supported jurisdictions, their formats and default formats.
When to use it
Useful when you want an assistant to turn a short description of work into a finished invoice document, especially for German B2B or public-sector e-invoicing formats, or for simple US PDF invoices, and to retrieve earlier invoices again.
Requirements
A remote Streamable HTTP endpoint added to an MCP-aware client; nothing to install locally. No authentication is declared. A sender email address is needed, and the first invoice from a new address requires a 6-digit code sent to that email. Network access to the hosted service.
Before you install
Invoice details, including sender and recipient names, addresses, VAT IDs and amounts, are sent to a third-party hosted service. The first invoice from a sender email triggers an email verification code. Generated invoices are documents only and are not tax or legal advice. Only Germany and the United States are supported at present.

Installation

In SourceWeft

  1. Open Scribo in the dashboard and add it to a workspace.
  2. Enable the server for the chats that should use its tools.

Web executable via Streamable HTTP. Remote servers run from the web runtime once configured in a workspace.

Use with an agent

Paste this prompt into Claude Code, Codex, Cursor or another agent — or into SourceWeft chat. The agent reads this server's install guide, shows you its publisher, endpoint and sign-in, and adds it to your client once you agree. Keys never go into a command.

Read https://sourceweft.com/mcp/io.github.causa-prima-ai%2Fscribo/install.md and connect the MCP server it describes to my client. Before changing any config, show me its publisher, endpoint and sign-in method and wait for my OK. Never put an API key in a command or in a file I would commit; ask me where it should come from.

Read the install guide the agent follows

Other MCP clients

Add this to your client's mcpServers config.

{
  "mcpServers": {
    "scribo": {
      "type": "http",
      "url": "https://scribo.causaprima.ai/mcp"
    }
  }
}

README

[A3 _ MCP server]

Scribo MCP Server

Free, AI-native e-invoicing — for any MCP client.

Contents

What is Scribo?

Scribo is a free, conversational e-invoicing tool. Describe an invoice in plain language — "bill Acme GmbH €2,400 for May design work" — and it drafts a structured invoice for you to review, download and send directly.

Just ask your AI agent about Scribo: it ships as an MCP server, a CLI, and a Claude/Codex skill, alongside a public HTTP API and a web app. Free forever — no credit card. You just need a sender email.

Built by Causa Prima — Scribo is built by Causa Prima, a company building agentic AI for the CFO office. It's our first freely available skill — an early glimpse of what we're building.

What is the Scribo MCP server?

The Scribo MCP server gives your AI assistant the ability to create invoices for you. It's a hosted Model Context Protocol endpoint — add its URL to your assistant once, then just ask for an invoice and it gathers the details and hands back a finished, compliant invoice in the chat, ready to download and send.

Because it's hosted, there's nothing to install or run locally. It works with any MCP-aware client — Claude Desktop, Claude.ai, Cursor, Cline, ChatGPT App, the OpenAI Codex CLI, and others. Free, no signup — your email is all you need.

Demo

https://github.com/user-attachments/assets/3e1fcca8-580b-448f-bb1c-bee5ee016b54

Getting started

Quickstart

Scribo's MCP server is hosted — there's nothing to install. Point your client at:

https://scribo.causaprima.ai/mcp

In Claude Desktop or Claude.ai: Customize → Connectors → Add custom connector, name it Scribo, paste the URL, and save. Then just ask:

Draft an invoice for 3 days of consulting at €1,200/day to Acme GmbH.

Scribo collects the missing details, verifies your sender email once, and returns a download link.

Using a different client? See the per-client setup below.

Setup & prerequisites

The server speaks MCP over Streamable HTTP (JSON-RPC 2.0, MCP spec ≥ 2025-03-26) with no auth. Any MCP-aware client connects with one setting — the URL https://scribo.causaprima.ai/mcp.

Claude Desktop / Claude.ai — Customize → Connectors → Add custom connector → name Scribo, paste the URL. On Team/Enterprise plans an org owner may need to add it once under Organization settings → Connectors.

Cursor — add to ~/.cursor/mcp.json (or workspace .cursor/mcp.json):

json
{ "mcpServers": { "scribo": { "url": "https://scribo.causaprima.ai/mcp" } } }

Cline — add to cline_mcp_settings.json:

json
{ "mcpServers": { "scribo": { "transport": "streamable-http", "url": "https://scribo.causaprima.ai/mcp" } } }

OpenAI Codex CLI — add to ~/.codex/config.toml, then restart Codex:

toml
[mcp_servers.scribo]url = "https://scribo.causaprima.ai/mcp"

Any other MCP client — configure a remote server at the URL above, transport Streamable HTTP, no auth.

Prefer a plain-bash setup with no connector in the loop? The Scribo skill covers Claude Code, Claude.ai, Claude Desktop, and Codex via simple helper scripts.

Verify. Ask your assistant: "list the jurisdictions Scribo supports."

Usage

How it works

You describe the invoice in plain language; your assistant calls Scribo's tools to build it. The server exposes four tools:

ToolWhat it does
create_invoiceGenerates a compliant invoice from the sender, recipient, and line-item details, and returns a durable download link.
verify_email_codeConfirms ownership of the sender email using the 6-digit code Scribo emails on the first invoice.
get_invoiceRe-fetches a previously generated invoice and a fresh download link.
list_supported_jurisdictionsLists which countries and formats are available.

A typical flow: you ask for an invoice → your assistant calls create_invoice and collects anything missing → on your first invoice from a new sender email, Scribo asks you to paste a 6-digit code (confirmed via verify_email_code) → your assistant retries and hands back a download link — a PDF with the matching EN 16931 XML embedded. On clients that render widgets (e.g. the ChatGPT App), the invoice appears as a card with a download button.

The server also registers five workflow prompts (generate_invoice, german_b2b_invoice, german_b2g_xrechnung, us_plain_pdf_invoice, redownload_invoice) — clients that surface prompts show them as slash-command-style starters.

Full tool schemas and sample payloads are in schemas/ and examples/, and in the MCP docs.

Examples

Things you can say to your assistant once Scribo is connected:

German B2B invoice (ZUGFeRD)

Invoice Beispiel GmbH for 12 hours of web development at €110/hour, 19% VAT. I'm Example GmbH, VAT ID DE123456789.

Returns a ZUGFeRD invoice — a PDF a human can read, with EN 16931 XML embedded for the recipient's accounting system.

German public-sector invoice (XRechnung)

Same client, but it's for the City of Munich — the Leitweg-ID is 04011000-1234512345-06.

A Leitweg-ID tells Scribo this is a B2G invoice, so it produces XRechnung, the format German public authorities require.

US invoice (plain PDF)

Bill Acme Inc. $4,000 for a brand strategy workshop.

A clean PDF invoice — no e-invoice XML, since the US has no e-invoicing mandate.

Re-download a past invoice

Send me the download link for the invoice I made for Beispiel GmbH last week.

Scribo returns a fresh download link for an invoice you've already generated.

Compliance

Scribo emits invoices conforming to EN 16931, the European e-invoicing standard, with the relevant national CIUS. Every EN 16931 output (ZUGFeRD, XRechnung) is validated against the Invopop-hosted validator at generate-time — output that fails the rule set never reaches the user. US plain PDFs carry no EN 16931 XML and are rendered directly.

Supported formats

JurisdictionFormatStatus
Germany (B2B)ZUGFeRD COMFORT (PDF/A-3 hybrid + CII XML)✅ Live
Germany (B2G)XRechnung (UBL / CII)✅ Live
United StatesPlain PDF (no XML, no e-invoice claim)✅ Live
FranceFactur-X EN 16931🔜 Coming soon
SpainFacturae🔜 Coming soon
Belgium / NL / LU / ATPeppol BIS 3.0 UBL🔜 Coming soon

Disclaimer: Scribo generates and validates compliant invoice documents. It is not tax or legal advice — Scribo does not determine your tax obligations, VAT treatment, or filing requirements.

FAQ

Is Scribo really free?

Yes — free forever. No credit card, no subscription, no paywall before your first invoice. You just need a sender email.

Do I need an account or signup?

No signup form. On your first invoice, Scribo verifies the sender email — a 6-digit code (or one-click link) arrives at that address; one verification covers ~30 minutes of invoicing. The same email doubles as your magic-link login for re-downloads later.

Which countries and formats are supported?

Live today: Germany — ZUGFeRD (B2B) and XRechnung (B2G) — and the United States (plain PDF). Coming next: France (Factur-X), Spain (Facturae), and Belgium / NL / LU / AT (Peppol BIS 3.0).

What does "EN 16931-compliant" actually mean here?

Every EN 16931 output (ZUGFeRD, XRechnung) is validated against the EN 16931-1:2017 rule set (via the Invopop-hosted validator) before it's returned. Output that fails validation never reaches you. US plain PDFs carry no EN 16931 XML, so no schematron validation applies.

Is the US version compliant?

Yes. There is no US e-invoicing mandate, so Scribo produces a fully compliant plain PDF.

Does Scribo give tax or legal advice?

No. Scribo generates and validates compliant invoice documents. It does not determine your tax obligations, VAT treatment, or filing requirements.

How do AI agents / LLMs use Scribo?

Scribo is built to be operated by an agent. It ships as an MCP server, a CLI, and a Claude/Codex skill, plus a public HTTP API and a web app — all on the same backend. An agent can discover Scribo, create an invoice, and return the file on a user's behalf.

Who builds Scribo?

Causa Prima — a company building agentic AI for the CFO office. Operated by Causa Prima Germany GmbH, Munich.

Resources

Other Scribo surfaces

License

Proprietary — UNLICENSED. © Causa Prima Germany GmbH. All rights reserved. Distributed for use against the public Scribo API; not open-source. See LICENSE.

Source: README.md at commit a17a560

Tools

4

create_invoice

Generate Invoice

Generate an invoice. **Phase 1 supports Germany (DE) and the United States (US) only** — DE emits an EN 16931-compliant XRechnung (UBL by default, CII via format_override) or ZUGFeRD COMFORT, US emits a plain PDF. Any other sender jurisdiction is rejected with `unsupported_jurisdiction`. The format is selected automatically from the sender's country (override with `format_override`, or auto-select XRechnung UBL by setting `recipient.leitweg_id`); German output is validated against EN 16931 before bytes are returned. **B2G submission is NOT included yet** — for XRechnung the response carries the legally binding XML, a PDF preview, and a `submission` object explaining how to upload the XML manually (ZRE / OZG-RE / Peppol direct send is on the roadmap). Surface that limitation to the user before they commit to a B2G invoice. After email verification succeeds, returns a durable signed download URL plus the resolved format. Synchronous — blocks until validation passes; use `get_invoice` afterwards to re-mint the download URL on demand. Safe to retry with identical inputs: when no `idempotency_key` is supplied the client derives one, so repeats return the original invoice. The exception is `invoice_source_review_required`: the invoice number is already used for that recipient with different facts, or the recipient matches more than one business partner or its name or tax ID conflicts with the business partner on record, and nothing was recorded — do not retry unchanged; when `details.reason` is `unresolved_parties` ask the user to check the recipient's name and tax ID, otherwise ask for a different invoice number. `invoice_admission_busy` means another invoice is being recorded; retry the same call shortly. `invoice_storage_unavailable` means storing the invoice timed out and nothing was recorded; retry the same call shortly. If this returns `verification_required`, ask the user to paste the 6-digit code from the verification email, call `verify_email_code`, then retry th

Parametersnoteslocalesenderrequiredcurrencyrequireddue_daterecipientrequiredissue_dateline_itemsrequiredjurisdictiondelivery_datepayment_meanspayment_terms+5 more

get_invoice

Fetch Invoice

Fetch a previously generated invoice by its `invoice_id` and return its current metadata plus a freshly signed download URL. Read-only and tenant-scoped — cross-tenant lookups return 404. Use this after `create_invoice` to re-download bytes from a different device, or to obtain a new signed URL after the original expires.

Parametersinvoice_idrequired

list_supported_jurisdictions

List Supported Jurisdictions

List jurisdictions Scribo can emit invoices for, with each jurisdiction's available formats and the default format applied when no override is given. Phase 1 returns Germany (DE — XRechnung / ZUGFeRD) and the United States (US — plain PDF) only. Read-only and side-effect-free; safe to call before `create_invoice` to confirm a country is supported. Returns an array of `{ jurisdiction, formats[], default_format }`.

Takes no parameters.

verify_email_code

Use this after `create_invoice` returns `verification_required`. Arguments: `{ challenge_id, code }`. On success returns a `verification_token`. Retry `create_invoice` with the same arguments plus that `verification_token` passed in its `verification_token` field. The token is reusable for ~30 min, so thread the same one into every subsequent `create_invoice` for the same sender email until it expires. Only ever call this with a code the user gave you: attempts are capped, a handful of failures revokes the challenge and forces the user to request a new email, and a `rate_limited` error means stop and tell them to wait, not retry.

Parameterscoderequiredchallenge_idrequired

Version history

1
  1. v1.0.0LatestSep 16, 2026

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