Developers and AI
The website and public API use the same checked content and calculator availability. Calculations are unavailable; there is no working calculation endpoint to call.
Public HTTP
The intended public API base is https://api.adad.app. The following routes are implemented in this draft. Public-domain delivery still needs a separately approved deployment; these instructions do not claim that the hosted API has been cut over.
- GET /pages lists public page summaries.
- GET /pages/home reads this site's home page as checked JSON, including Markdown.
- GET /calculators lists calculator availability.
- GET /calculators/annual reads annual calculator availability.
Unknown pages return 404. Invalid identifiers return 400. The annual calculator reports unavailable with unqualified tax years. No login or API key is required for these read operations.
Effect RPC
The implemented HTTP transport is POST /rpc at the same API base. The owning contract provides ListPages, GetPage, ListCalculators and GetCalculator. Use the checked adad RPC client with the matching contract. Its wire format is a native Effect protocol, rather than an arbitrary JSON calculation request.
Browser requests omit credentials. The API admits only the exact matching website origin; a local API instance admits its configured local website origin.
AI discovery and Markdown
Read llms.txt, the sitemap or this page's Markdown copy to discover public information. These files describe available read operations only.
Remote MCP
The draft implements POST /mcp at the intended API base. It exposes list_pages, get_page, list_calculators and get_calculator. Get operations take an id; list operations take an empty object. These tools read public information only. No login or API key is required.
The selected MCP version is 2026-07-28. It uses per-request metadata rather than an initialise or session handshake. Each POST needs Accept for application/json and text/event-stream, MCP-Protocol-Version, MCP-Method and MCP-Name for a tool call. Header version, method and tool name must agree with the request body. Discovery uses server/discover. Older versions and subscriptions are unavailable.
Non-browser clients may omit Origin. Browser requests require the exact matching website origin and omit credentials. Requests are limited to 32 KiB, responses to 256 KiB, unfinished work to ten seconds and concurrent requests to sixteen. Hosted delivery still requires separately approved deployment.
Browser tools
A supporting browser can use the same four read tools while the annual calculator page is open at the matching website origin. The tools call the website's existing checked RPC client. Leaving that page removes registration and stops unfinished calls. Browsers without WebMCP show an explicit unsupported message; a refused registration is reported separately.
No calculation tool is advertised. Annual availability remains unavailable with unqualified tax years. Never provide financial information to these read tools.