# What ChengOS Is

> Applies to: ChengOS v0.1.0+ ｜ Last verified: 2026-08-12 ｜ Source: root `README.md`, `deploy/README.md`

ChengOS is a visual platform for building, running, and publishing AI workflows and agents.
You assemble typed nodes on a canvas into a directed graph, and the platform runs that graph
on a Rust engine — then exposes the result as a chat interface, a published app, a scheduled
job, an API endpoint, or a terminal session, without you rebuilding anything.

## What it is, concretely

Five pieces ship together:

| Piece | What it is |
|---|---|
| **`cheng-api`** | The Rust backend: DAG execution engine, REST + WebSocket API, node library, credential vault, scheduler, vector retrieval |
| **`cheng-ui`** | The browser workflow editor and admin console, built on React Flow |
| **`cheng-app`** | The chat gateway: embeddable web widget, responsive H5/PWA, and messaging-channel routing |
| **`cheng` CLI** | A terminal client that connects to a local or remote server, in the style of Claude Code or Codex |
| **`deploy/`** | One script, `chengos.sh`, that installs and operates all of the above |

## What you can build with it

- Visual AI and automation workflows from reusable nodes and subflows.
- ReAct agents that discover and invoke tools, MCP servers, and Skills.
- Chat applications for web, mobile, embedded widgets, and messaging channels.
- Local document, spreadsheet, RAG, and multimodal processing pipelines.
- Terminal agents that operate against a local or remote ChengOS server.

## What makes it different

**Credentials never reach the model.** API keys, tokens, and passwords live in an encrypted
vault. Nodes hold a *reference*; the real secret is injected server-side at the moment a
network call or shell command is actually made. Even an autonomous agent choosing its own
tool calls never sees a key in its prompt context, which closes off prompt-injection as a
route to credential theft.

**Documents and spreadsheets are local.** There is a built-in canvas for rich text/`.docx`
and spreadsheets/`.xlsx`. You do not connect Google Sheets or Feishu to let an agent edit a
table — the data stays in the workspace sandbox.

**MCP is native, in both directions.** ChengOS consumes external MCP servers over stdio,
SSE, and HTTP, and also *exposes* workflows as MCP servers. An agent discovers external
tools, prompts, and resources automatically.

**Node forms are generated, not written.** A node declares its inputs as a JSON Schema with
`x-*` UI hints; the editor turns that into a form. Change a node's inputs on the backend and
the property panel follows, with no frontend work.

**The engine is Rust.** The DAG is planned statically into stages, then scheduled
concurrently with a semaphore-bounded task pool, streaming progress over WebSocket.

## How the pieces talk

```text
                      ┌───────────────────────────────┐
                      │   Backend core (cheng-api)    │
                      │  Rust DAG engine / REST + WS  │
                      └───────────────┬───────────────┘
                                      │
        ┌─────────────────────────────┼─────────────────────────────┐
        ▼                             ▼                             ▼
┌────────────────┐           ┌────────────────┐           ┌────────────────┐
│ Visual editor  │           │  Chat gateway  │           │  Terminal CLI  │
│  (cheng-ui)    │           │  (cheng-app)   │           │    (cheng)     │
│ React Flow     │           │ Widget / H5    │           │ Local / remote │
└────────────────┘           └────────────────┘           └────────────────┘
```

Every client is an ordinary consumer of the same REST + WebSocket API. There is no privileged
internal channel — see [the REST API overview](/docs/api-rest-overview).

## Licensing

ChengOS is currently **free to use** but **not open source**. You may use it at no cost for
personal and commercial office automation; the source is not published. The stated plan is a
free Community Edition (the current release, with core office-automation features) and a paid
Enterprise Edition adding team collaboration, permission management, and dashboards.

Business and enterprise enquiries: `hello@chengrouter.com`.

## Where to go next

- [Core concepts](/docs/core-concepts) — the vocabulary, in one page.
- [System overview](/docs/system-overview) — the components and deployment shapes.
- [Install ChengOS](/docs/install-chengos) — get it running.
- [Your first workflow](/docs/quickstart-first-workflow) — build something.