# Eulernen auth.md

Agents need no registration and no credentials for eulernen.de.

## Audience

Any AI agent or client that looks up Eulernen learning posters for a user.

## Registration and credentials

- Registration endpoint: none. There is nothing to register for.
- Supported method: anonymous access without credentials.
- Credential use: none. Send no `Authorization` header, API key or cookie; none is issued or checked.
- OAuth: not offered, so there is no `/.well-known/oauth-protected-resource` or `/.well-known/oauth-authorization-server`.

## Endpoints

| Endpoint | Protocol | Access |
|---|---|---|
| `GET https://eulernen.de/api/v1/catalog.json`, `GET https://eulernen.de/api/v1/sets`, `GET https://eulernen.de/api/v1/sets/{id}` | JSON, described by [OpenAPI](https://eulernen.de/api/openapi.json); `/api/catalog.json` is an alias | public, anonymous, read-only |
| `POST https://eulernen.de/mcp` | MCP Streamable HTTP, tools `list_sets` and `get_set` ([server card](https://eulernen.de/.well-known/mcp/server-card.json)) | public, anonymous, read-only |
| `POST https://eulernen.de/a2a` | A2A JSON-RPC, `SendMessage` and `message/send` ([agent card](https://eulernen.de/.well-known/agent-card.json)) | public, anonymous, read-only |

All three return catalogue data only. Nothing can be bought, booked, ordered or changed through them. Together they allow 60 requests per 60 seconds per client IP; above that the answer is 429 with `Retry-After`.

There is no sandbox and nothing to provision: production is public and read-only. Examples, errors and versioning: [developer docs](https://eulernen.de/docs).

## Purchases

A human buys on Etsy: https://www.etsy.com/shop/Eulernen. The Etsy listings are being added; prices and availability are shown only there. Do not buy on a user's behalf without their explicit confirmation of item and total.

## Contact

info@eulernen.de