Dishmath

dishmath

Restaurant arithmetic that runs entirely on your own machine: what a plate costs to make, what to charge for it, how a recipe changes between portion counts, and which dishes a guest with an allergy must avoid. There is no account, no key and no network call — every answer is computed locally from the numbers you pass in.

The four calculations

• Food cost — add up a dish ingredient by ingredient. Alongside the plate cost you can ask for the selling price that lands on a target food-cost percentage, and for the percentage you are really running at today's price.
• Menu price — start from a plate cost and a target food-cost percentage. You get the net price, the price with VAT added, that price rounded up to a clean step (0.50, 1.00, …), the gross profit per plate net of tax, and the food-cost percentage the rounded price actually gives you.
• Recipe scaling — give a recipe written for one number of portions and get every quantity rewritten for another. When the ingredients carry unit costs, the batch cost and the cost per portion come with it.
• Allergen matrix — declare the allergens in each dish and get the dish-by-allergen table used under EU Regulation 1169/2011 (Annex II), plus the list of dishes to avoid for each of the 14 allergens. Names are accepted in English or Italian, and common names work too: "shrimp" counts as crustaceans, "dairy" as milk. The tool never guesses allergens from a dish's name — a dish with none declared is reported that way.

Money is rounded half-up to two decimals and percentages to one decimal. An optional ISO currency code (default EUR) changes only how amounts are printed.

Worked example, plate cost €3.20 at a 30% target with 10% VAT and a 0.50 rounding step:

Net price (before tax): €10.67

Price incl. 10% tax: €11.74 Menu price (rounded up to 0.5): €12.00 Gross profit per plate (net of tax): €7.71 Real food cost after rounding: 29.3%

CLI

npx @reneturcios/dishmath menu_price_calculator '{"plate_cost":3.20,"target_food_cost_percent":30,"vat_percent":10,"rounding_step":0.50}'

npx @reneturcios/dishmath food_cost_calculator '{"ingredients":[{"name":"flour","quantity":0.5,"unit":"kg","unit_cost":1.20}],"target_food_cost_percent":30}' npx @reneturcios/dishmath recipe_scaler '{"ingredients":[{"name":"flour","quantity":500,"unit":"g"}],"original_portions":4,"target_portions":6}' npx @reneturcios/dishmath allergen_matrix '{"dishes":[{"name":"Shrimp pasta","allergens":["shrimp","gluten"]}]}' npx @reneturcios/dishmath --version

Each tool subcommand takes a single JSON argument string and prints the result as plain text. Exit codes: 0 on success, 1 on a calculation or validation error, 2 on a usage error.

MCP

npx -y @reneturcios/dishmath mcp

MCP client configuration:

{

"mcpServers": { "dishmath": { "command": "npx", "args": ["-y", "@reneturcios/dishmath", "mcp"] } } }

Tools exposed over MCP: food_cost_calculator, menu_price_calculator, recipe_scaler, allergen_matrix.

Docker

docker run -i ghcr.io/cloudcorprecords/dishmath

docker run --rm ghcr.io/cloudcorprecords/dishmath menu_price_calculator '{"plate_cost":3.20,"target_food_cost_percent":30,"vat_percent":10,"rounding_step":0.50}'

The container's default command is mcp, so the first form starts the stdio MCP server; any other arguments reach the CLI.

Development

npm install

npm run build npm test npm run dev

License

MIT — see LICENSE.