What is ksefnik CLAUDE.md?

Project instructions for Ksefnik, a TypeScript software library that matches Polish KSeF e-invoices with bank transactions. It describes the project's packages, tools, testing approach, and coding conventions.

Use it when working on Ksefnik's shared types, reconciliation engine, bank parsers, offline test server, MCP server, command-line tool, or package and test setup.

It gives contributors the context needed to change the right package and follow the project's existing structure. A monorepo is one repository containing several related packages that are developed together.

How CodeFormers-it/ksefnik configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to CodeFormers-it/ksefnik. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/CodeFormers-it/ksefnik/main/CLAUDE.md

Clone the repo

git clone --depth 1 https://github.com/CodeFormers-it/ksefnik

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/codeformers-it/ksefnik/claude-md/github.svg)](https://agentmods.dev/instructions/codeformers-it/ksefnik/claude-md)

Your own site

<a href="https://agentmods.dev/instructions/codeformers-it/ksefnik/claude-md"><img src="https://agentmods.dev/badge/instructions/codeformers-it/ksefnik/claude-md/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/codeformers-it/ksefnik/claude-md"><img src="https://agentmods.dev/badge/instructions/codeformers-it/ksefnik/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 796 This file is loaded in full into every session.

When invoked 796 The same file — it is already loaded in full.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.00796	$0.00796
Opus 5.5	$0.00318	$0.00318
Sonnet 5.5	$0.00159	$0.00159
Haiku 4.5	$0.00080	$0.00080

Measured 2mo ago against content hash f6a46418231c, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

ksefnik CLAUDE.md scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2mo ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

CLAUDE.md · 80 lines

How it starts

The opening of the file, as written. The whole thing — 80 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Ksefnik — TypeScript SDK

Project Overview

Open-source TypeScript SDK for KSeF (Polish National e-Invoice System) reconciliation. Core value: matching KSeF invoices with bank statement transactions.

Organization: CodeFormers-it Repo: CodeFormers-it/ksefnik (private → public when ready) Sister repo: CodeFormers-it/ksefnik-pro (always private) Domain: ksefnik.pl

Tech Stack

Component	Choice
Language	TypeScript (strict)
Runtime	Node.js 22
Package Manager	pnpm (workspace monorepo)
Validation	Zod
Testing	Vitest
KSeF API client	@ksef/client (adapter pattern)
MCP SDK	@modelcontextprotocol/sdk
CLI	Commander.js
Interactive	@clack/prompts
Fuzzy matching	fuzzball
MT940 parsing	mt940js
DB (local)	bun:sqlite
Binary	bun build --compile

Monorepo Structure

packages/
  shared/        @ksefnik/shared    — Zod schemas, types, plugin interface
  core/          @ksefnik/core      — SDK facade, reconciliation engine, bank parsers
  simulator/     @ksefnik/simulator — Offline KSeF mock server
  mcp/           @ksefnik/mcp       — MCP server (thin wrapper on core)

apps/
  cli/           @ksefnik/cli       — CLI entry point → standalone binary

Key Conventions

pnpm workspace with apps/* and packages/* (same as codeformers-website)
SDK-first: all logic lives in @ksefnik/core. CLI, MCP, and hosted API are thin wrappers.
Plugin system: pro features loaded via try { await import(pkg) } catch {} — missing = free tier.
No DRM: zero license validation in runtime, zero phone-home.
Zod everywhere: all domain models (Invoice, BankTransaction, Match) are Zod schemas.
Money as integers: amounts in grosze (1 PLN = 100), never floats.
Adapter pattern: @ksef/client wrapped in adapter for retry, cache, swappability.
.nvmrc: 22
Formatting: Prettier (no ESLint in root)

Architecture Principles

Ksefnik facade with namespaces: invoices, bank, reconciliation, plugins
Factory: createKsefnik()
Reconciliation engine: 6-pass pipeline (KSeF ref → exact NIP → invoice ref → fuzzy → partial → proximity)
Each pass implements ReconciliationPass interface with order number (core: 50-500, plugins: 600+)
Bank parsers implement BankStatementParser protocol with auto-detection

Read the full file on GitHub · 80 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

2mo ago First seen · 80 lines · 796 tokens per session scan A f6a46418231c

Subscribe to this mod's changes

ksefnik CLAUDE.md is an instructions file published in the GitHub repository CodeFormers-it/ksefnik (13 stars, last pushed 5mo ago), licensed MIT. It adds 796 tokens to every session, about $0.0032 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

Finance and fintech bank-statement claude e-faktura e-invoice einvoice fintech

ksefnik CLAUDE.md next to 6 instructions from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
ksefnik CLAUDE.mdCodeFormers-it/ksefnik	Instructions file	13	5mo ago	MIT	A	796	Claude Code
vscode buildNext.instructions.mdmicrosoft/vscode	Instructions file	195k	today	MIT	A	9,719	GitHub Copilot
next.js AGENTS.mdvercel/next.js	Instructions file	143k	today	MIT	A	7,461	Codex, OpenCode
vscode oss-third-party-notices.instructions.mdmicrosoft/vscode	Instructions file	195k	today	MIT	A	5,685	GitHub Copilot
langchain AGENTS.mdlangchain-ai/langchain	Instructions file	149k	yesterday	MIT	A	4,680	Codex, OpenCode
vscode copilot-instructions.mdmicrosoft/vscode	Instructions file	195k	today	MIT	A	3,093	GitHub Copilot
vscode model-prompts.instructions.mdmicrosoft/vscode	Instructions file	195k	today	MIT	A	2,022	GitHub Copilot

ksefnik: Instructions file for Claude Code