> ## Documentation Index
> Fetch the complete documentation index at: https://docs.eucaengine.com/llms.txt
> Use this file to discover all available pages before exploring further.

# API reference

> The typed HTTP API for the agent-native game engine — JSON over HTTP on localhost:3917.

Euca exposes one typed HTTP API. Everything an agent does — build, play, experiment — goes
through it. The endpoint pages in this section are rendered from a **hand-maintained OpenAPI
snapshot** (`openapi.json`). It was originally produced from the engine's request/response
types; the generator has since been retired, so the spec is now curated by hand and can drift
from the live routes — the canonical, always-current schema is the running server itself
(`GET /schema`, and `euca discover` / `euca explain` from the CLI).

## Conventions

* **Base URL** — `http://localhost:3917` for a local server.
* **Content type** — send `Content-Type: application/json` on every request with a body.
* **Identifiers** — entities are addressed by `id`; pass the `generation` returned by
  `/spawn` alongside the `id` where an endpoint asks for it.
* **Clients** — it is plain JSON over HTTP, so any language works. Examples are shown in
  cURL, Python (`requests`), and Rust (`reqwest`).

## Authentication

The local, self-hosted server is **unauthenticated by default** — no global gate, so token-less
calls just work; run it in a trusted environment. The engine also ships **opt-in Ed25519 auth**:
install an `AuthStore` and `POST /auth/login` verifies an Ed25519 signature and issues a session
token (`GET /auth/status` validates it), with a per-agent ownership layer on scoped scene routes.
It is **optional and not required** to use the engine locally. Hosted or benchmark access can
additionally layer an API key at the hosting tier.

## Coverage

This reference covers the agent's HTTP surface — **\~114 endpoints** — across world,
simulation, rules, forks, snapshots, scenes & scenarios, gameplay (units, items, abilities &
effects), assertions & manifest, camera & render, UI, animation, audio, particles, terrain,
navigation, input, scripting, and AI asset generation. The OpenAPI snapshot below is curated
by hand; treat `GET /schema` on the running server as the authoritative, always-current
schema. Engine version: **1.1.0**.