# KAMMAREN
> Deterministic tax engine for Swedish limited companies (aktiebolag).
> LLMs classify. Code calculates. Humans decide.

## What this is
KAMMAREN is an open source calculation kernel for Swedish tax optimization.
It sits between bookkeeping systems and decisions. Every answer is deterministic,
verified against Skatteverket's published tables, and logged in a cryptographic
audit trail (SHA-256 hash chain).

## MCP Server (live)
Endpoint: https://mcp.kammaren.nu/mcp
Protocol: MCP (Model Context Protocol)
Tools available:
- optimize_312: Swedish 3:12 salary/dividend tax optimization
  Inputs: profit_before_salary, municipal_tax_rate, church_member, salary_strategy
  Output: SkillOutput with strategies, net amounts, legal references, disclaimer

## npm Package
Package: kammaren-tax-engine
Registry: https://www.npmjs.com/package/kammaren-tax-engine
Install: npm install kammaren-tax-engine

## Web Calculator
URL: https://kammaren.nu
Tool: 3:12 tax optimization with 4 salary strategies, 290 municipalities

## Source Code
Repository: https://github.com/Baltsar/kammaren
License: AGPL-3.0-or-later
Language: TypeScript (Bun runtime)
Test suite: 258 golden case assertions, all verified against official tables

## Skills (calculation modules)
- tax-optimizer: 3:12 salary/dividend optimization (live)
- ag-avgifter: employer contributions 31.42% (built, verified 19/19)
- moms: VAT 25/12/6/0% + reverse charge (built, verified 34/34)
- bolagsskatt: corporate tax + periodiseringsfond (built, verified 46/46)
- k10: shareholder tax, 2026 additive model (built, verified 34/34)
- 29 more planned (löneberäkning, representation, pension, kryptoskatt, etc.)

## Legal Sources
Swedish Income Tax Act (IL) chapter 57
SKV 433 (Skatteverket calculation tables)
Prop. 2025/26:1 (new 3:12 rules effective 2026)
Social Insurance Contributions Act (SFL)
VAT Act (ML)

## Contact
Website: https://kammaren.nu
Email: info@kammaren.nu
Build log: https://kammaren.nu/build