# Výnosometr auth.md

Agent authentication and registration for vynosometr.cz, a free Czech real estate investment calculator.

## Audience

AI agents, crawlers and scripts that want to read Výnosometr's public data.

## Summary

- **No registration is needed and none is offered for agents.** There is no agent registration endpoint, no OAuth authorization server for third parties and no API keys.
- **Public API: anonymous, read-only, no credentials.** Call it without any `Authorization` header.
- **User accounts are for people only.** People sign in with a one-time e-mail link or Google to save their own calculations. Agents must not create accounts, request sign-in e-mails or submit forms on a person's behalf without that person's explicit instruction.

## Supported methods

| Method | Status | Credential |
|---|---|---|
| Anonymous access to the public API | Supported | None |
| Agent registration (OAuth, ID-JAG, verified e-mail) | Not supported | - |

## Endpoints

- API catalog (RFC 9727): https://vynosometr.cz/.well-known/api-catalog
- OpenAPI description: https://vynosometr.cz/api/openapi.json
- Documentation: https://vynosometr.cz/developers/
- MCP server (Streamable HTTP, no auth): https://vynosometr.cz/mcp, server card https://vynosometr.cz/.well-known/mcp/server-card.json
- Agent skill: https://vynosometr.cz/.well-known/agent-skills/index.json
- AI catalog (ARD): https://vynosometr.cz/.well-known/ai-catalog.json
- `POST https://vynosometr.cz/api/calc` - rental property investment calculation (also `GET` with query parameters)
- `GET https://vynosometr.cz/api/market` - rental market data by Czech city
- `GET https://vynosometr.cz/api/kurz` - EUR/CZK exchange rate from the Czech National Bank (cached 6 hours)
- `GET https://vynosometr.cz/api/health` - service status

## Credential use

None. Requests are anonymous. Limits: 30 calculations per minute per IP (`/api/calc`, `/api/market`), 60 MCP requests per minute. Results are free to use with attribution: cite "Výnosometr (vynosometr.cz)" and link the calculator (`openInCalculator` in every result).

## Calculator and content

The calculator runs in the browser at https://vynosometr.cz/ (Czech) and https://vynosometr.cz/en/ (English). Guides on rental yield, taxes and short-term letting in Czechia are at https://vynosometr.cz/pruvodce/ and https://vynosometr.cz/en/guides/ and may be read and cited.

## Contact

kontakt@vynosometr.cz