// Developers

Build with ARCANA without guessing the interface.

ARCANA is OTNEL's terminal-native AI engineering workbench. This page is the canonical developer entry point for evaluating the product, installing the Community edition, discovering the public website API, understanding authentication, and locating machine-readable resources. Local Community use is free and does not require an ARCANA license: bring your own supported model-provider credentials and follow the quickstart. ARCANA licenses are used for optional hosted proxy and cloud features rather than basic local operation.

Start locally for free

Use the Quick Start to install the arcana-ai package and launch the arcana CLI or TUI. Community/BYOK mode keeps model billing with the selected provider. No sales conversation is required to evaluate local ARCANA. Run arcana doctor after installation to verify configuration and detected provider credentials.

Public REST API

Machine clients should begin at GET /api. Public unauthenticated operations include GET /api/status, GET /api/feedback, and POST /api/feedback. Authenticated account, profile, workspace, session, and billing operations are described separately. Use the OpenAPI 3.1 document or the YAML representation for operation IDs, request and response schemas, security requirements, and recovery behavior.

Authentication

Do not assume every ARCANA endpoint requires a key. The OpenAPI security declaration is authoritative. Public status and feedback endpoints are intentionally reachable without authentication. Account-oriented operations may require a Bearer credential obtained through ARCANA's documented authentication flow. The CLI can pair with an ARCANA account using arcana console login; local Community/BYOK operation remains separate from that hosted account flow.

Agent-readable discovery

Automated clients can read llms.txt, agents.md, the Agent Skills Discovery index, the RFC 9727 API catalog, and the sitemap. The Agent Skills index follows discovery schema 0.2.0 and points to a focused ARCANA developer-workbench skill with an integrity digest.

MCP scope

ARCANA supports MCP as a client and can connect to configured MCP servers, including remote Streamable HTTP servers. The public ARCANA website is not currently advertised as a hosted MCP server. Clients probing /.well-known/mcp/* should therefore treat HTTP 404 as an intentional signal rather than infer a server capability from an application-shell response.

Errors and recovery

Unknown API routes return structured JSON errors with a stable error code, human-readable message, and resolution hint. Unknown website resources return a real HTTP 404 and direct agents back to documentation, the sitemap, llms.txt, and OpenAPI. This behavior is intentional so automated clients can distinguish a missing resource from a valid application page.