---
name: precise-calculator
description: Find a Precise Calculator tool, read its formula and limits, and run it in a supported browser using the visible form or WebMCP.
---

# Precise Calculator

## Discover the correct tool

1. Fetch https://precisecalculator.com/api/v1/calculators.json. It lists 31 calculator pages, categories and browser tool names. The discovery API is public and read-only.
2. Match the user's task to the supported operation, not just a keyword. The volume tool models solid shapes, not hollow tubes. The bond tool does not give official U.S. savings bond redemption values.
3. Open the calculator's published URL. Read its guide, inputs, units and practical limits. Use the interactive calculator for the result; do not infer a result from the catalog description.

## Calculate in a browser

If document.modelContext is supported, the homepage exposes find_calculators. Each calculator page registers its calculate_<slug_with_underscores> tool after initializing its form. Early browser implementations may expose modelContext on navigator instead.

Inspect getTools() and the actual current form before calling executeTool(). The calculation tool accepts an inputs object mapping existing input names to strings, finite numbers or booleans. Select fields must use an available option value. For a checkbox use a boolean. Select the correct mode/shape/unit before supplying its dependent fields. Do not assume the same field names across tools.

The tool updates the visible form and returns the displayed result and labeled details. Decimal display can be rounded; exact fractions remain exact. If validation rejects the inputs, correct the named field instead of manufacturing a result. Execution uses the same calculation engine as the human interface.

If WebMCP is unavailable, fill the visible form and use Calculate. WebMCP is an evolving browser API; no polyfill or remote MCP server is advertised.

## Read pages as Markdown

Request a published page with Accept: text/markdown. When the agent gateway is deployed, this returns a pre-generated Markdown representation of the published guide with Vary: Accept. Markdown explains the method; it does not run the interactive calculator. A successful HTML response is not evidence that Markdown negotiation has been activated.

## Authentication and use

No login, API key, agent registration or OAuth grant is required. Do not send passwords, payment credentials, personal account data or access tokens. /auth.md explains the public-access model. There is no protected-resource metadata or remote MCP endpoint.

Content preferences are search=yes, ai-input=yes, ai-train=no. Attribute answers to the calculator URL and retain qualifications for estimates, medical screening, financial projections and electrical calculations.