# What is Shelley?

> An open source coding agent that you run yourself and use from a browser tab.

Shelley is a coding agent. You tell it what you want; it gets there by running
shell commands, editing files, driving a browser, and showing you its work as it
goes. It is one binary that serves a web UI, so the place you use it is a browser
tab, on your laptop or your phone. Ask it to fix a bug, build a web site, set
up and run some software (say, a Marimo notebook on port 8000), or go read
something on the web, and anything in between.

It is mobile-friendly, web-based, multi-conversation, multi-modal, multi-model,
and single-user. It was built for [exe.dev](https://exe.dev/), where it comes
running on every VM, but it isn't exclusive to it: it runs anywhere you can run a
macOS or Linux binary.

## The shape of it

- **One process, one user.** `shelley serve` starts a web server and keeps
  everything in a SQLite database. There are no accounts and no sandbox; it runs
  commands as you. Read [Running it safely](/docs/security) before you expose it
  to anything.
- **Many conversations.** Each conversation is its own agent, with its own
  model and working directory. Run several at once. See
  [Conversations](/docs/conversations).
- **Tools that do things.** A shell, precise file patches, a headless browser,
  subagents, and more. See [Tools](/docs/tools).
- **Any model you like.** Anthropic, OpenAI, Gemini, Fireworks, and custom
  OpenAI-, Anthropic-, or Gemini-compatible endpoints. See [Models and API keys](/docs/models).
- **Yours to bend.** Guidance files ([AGENTS.md](/docs/agents-md)),
  [skills](/docs/skills), [MCP servers](/docs/mcp), and [hooks](/docs/hooks).
  Or ask Shelley to [change its own source](/docs/self-modifying); it
  rebases your changes onto each new release.

## Getting going

1. [Install it](/docs/install). One binary, or Homebrew, or from source.
2. [Give it a model](/docs/models). An API key in the environment is enough.
3. Run `shelley serve` and open the tab.

No keys, no install? Shelley is already running on every
[exe.dev](/docs/exe-dev) VM, behind exe.dev's auth, with models included.
[Try it](https://exe.dev/new).

## Where it came from

Shelley grew out of [Sketch](https://github.com/boldsoftware/sketch), an earlier
coding agent from the same people. Unsurprisingly, much of Shelley is written by
Shelley, Sketch, Claude Code, and Codex. It's Apache-2.0 licensed and
[on GitHub](https://github.com/boldsoftware/shelley). For the name and the
logo, see the [FAQ](/docs/faq#why-shelley).