Grundheim runs an open MCP server (Model Context Protocol). It lets your AI assistant calculate Swiss taxes, affordability and mortgage rates with grundheim.ch's official engines instead of guessing. Free, no account, in 10 languages.
https://agent.grundheim.ch/mcp
Streamable HTTP, no authentication, read-only tools. Works with any MCP-compatible AI platform.
Claude — 1. Click "Connect to Claude": claude.ai opens the "Add custom connector" dialog with the name and endpoint URL already filled in (or go to Settings > Connectors manually). 2. Review and confirm the entry. 3. In a new chat, ask Claude for example whether you can afford your target property. For Claude Code in the terminal:
Step-by-step guide: Grundheim in Claude: https://www.grundheim.ch/en/integrationen/claude
https://claude.ai/customize/connectors?modal=add-custom-connector&connectorName=Grundheim&connectorUrl=https%3A%2F%2Fagent.grundheim.ch%2Fmcp
claude mcp add --transport http grundheim https://agent.grundheim.ch/mcp
ChatGPT — 1. Open the Grundheim entry in the ChatGPT plugin directory (link above). 2. Choose "Add" and confirm. 3. Enable Grundheim in a new conversation via the plus menu. Without directory access: Settings > Security and login > Developer mode, then choose "+" under Plugins and paste the endpoint URL.
Step-by-step guide: Grundheim in ChatGPT: https://www.grundheim.ch/en/integrationen/chatgpt
https://chatgpt.com/plugins/plugin_asdk_app_6acb3c7ce3d8819188911ef4a4ce3818
Gemini — In the Gemini app: add the endpoint URL as a custom app under Settings > Connected apps (currently requires Google AI Ultra). For the Gemini CLI, install our extension:
gemini extensions install https://github.com/ParetoLabsCH/grundheim-mcp
Other clients — Cursor and VS Code install the server with one click; the link opens the app with the connection details prefilled.
cursor://anysphere.cursor-deeplink/mcp/install?name=grundheim&config=eyJ1cmwiOiJodHRwczovL2FnZW50LmdydW5kaGVpbS5jaC9tY3AifQ==vscode:mcp/install?%7B%22name%22%3A%22grundheim%22%2C%22type%22%3A%22http%22%2C%22url%22%3A%22https%3A%2F%2Fagent.grundheim.ch%2Fmcp%22%7DAll tools use the same calculation engines as the calculators on grundheim.ch: official ESTV tariffs, standard bank stress-test rules and daily updated rate data.
calculate_swiss_income_and_wealth_tax — Income and wealth taxes for all 2,122 Swiss municipalities (read-only)calculate_capital_withdrawal_tax — Lump-sum tax on pension fund or pillar 3a withdrawals (read-only)calculate_affordability — Affordability stress test to Swiss bank standards (read-only)calculate_purchase_costs — Purchase incidental costs (registry, notary, transfer tax) per canton (read-only)calculate_imputed_rental_value — Tax effect of the imputed rental value incl. the post-2028 reform (read-only)compare_rent_vs_buy — Rent vs. buy over a multi-year horizon (read-only)calculate_mortgage_costs — Monthly mortgage costs, tranche strategy and rate shock (read-only)estimate_break_penalty — Break penalty for exiting a fixed-rate mortgage early (read-only)evaluate_forward_mortgage — Forward mortgage: is locking the rate in advance worth it (read-only)compare_amortization_strategies — Direct vs. indirect amortization of the second mortgage via pillar 3a (read-only)compare_tranche_structures — Tranche planner: 10-year fixed, 5-year fixed and SARON under six rate worlds over ten years (read-only)calculate_pension_buyin — Pension fund buy-in: tax savings and comparison with private investing (read-only)benchmark_ask_price — Whether an asking price is high or low for its location (read-only)get_mortgage_rates — Current and historical mortgage rates across Swiss banks (read-only)get_municipality_profile — Municipality profile: tax multiplier, population, official sale prices (read-only)get_market_price_context — Market price context: median prices per m² from current listings (read-only)get_price_trend — Property price trend: national index and local ZH sale prices (read-only)rank_municipalities_by_tax — Municipality ranking by tax multiplier within a canton (read-only)get_safety_statistics — Safety statistics: burglaries per 1,000 residents (BFS) (read-only)search_tradespeople — Tradespeople near a Swiss place, from the commercial register (read-only)generate_handover_link — Creates a link to prefilled calculators on grundheim.ch (creates link)All tools can be used anonymously: no registration, no personal data passed to Grundheim. The gateway stores no conversation content; inputs are processed for the calculation only. The one exception: when the assistant creates a short link to a prefilled calculator at your request, we store the link's target address with the values it contains (such as purchase price or municipality) so that the link works. We log technical metadata (tool name, language, client type, timestamp, response time), see section 12 of the privacy policy. Please note: your conversation itself runs on the respective AI platform (OpenAI, Anthropic, Google) and is subject to its privacy terms.