## The open source software factory for expert engineers
AI coding agents are powerful but unpredictable. You either babysit every step or review a 50-file diff you don't trust. Arc gives you a middle path: define the process as a graph, let agents execute it, and intervene only where it matters. [Why Arc?](https://arc.dev/getting-started/why-arc)
[](LICENSE.md)
[](https://arc.dev)
```bash
curl -fsSL https://fabro.sh/install.sh | bash
```
---
## Key Features
| | Feature | Description |
| --- | ------------------------------ | ----------------------------------------------------------------------------------------------------- |
| 🔀 | Deterministic workflow graphs | Define pipelines in Graphviz DOT with branching, loops, parallelism, and human gates. Diffable, reviewable, version-controlled |
| 🙋 | Human-in-the-loop | Approval gates pause for human decisions. Steer running agents mid-turn. Interview steps collect structured input |
| 🎨 | Multi-model routing | CSS-like stylesheets route each node to the right model and provider, with automatic fallback chains |
| ☁️ | Cloud sandboxes | Run agents in isolated Daytona cloud VMs with snapshot-based setup, network controls, and automatic cleanup |
| 🔌 | SSH access and preview links | Shell into running sandboxes with `arc ssh` and expose ports with `arc preview` for live debugging |
| 🌲 | Git checkpointing | Every stage commits code changes and execution metadata to Git branches. Resume, revert, or trace any change |
| 📊 | Automatic retros | Each run generates a retrospective with cost, duration, files touched, and an LLM-written narrative |
| ⚡ | Comprehensive API | REST API with SSE event streaming and a React web UI. Run workflows programmatically or as a service |
| 🦀 | Single binary, no runtime | One compiled Rust executable with zero dependencies. No Python, no Node, no Docker required |
| ⚖️ | Open source (MIT) | Full source code, no vendor lock-in. Self-host, fork, or extend to fit your workflow |
---
## Example Workflow
A plan-approve-implement workflow where a human reviews the plan before the agent writes code:
```dot
digraph PlanImplement {
graph [
goal="Plan, approve, implement, and simplify a change"
model_stylesheet="
* { llm_model: claude-haiku-4-5; reasoning_effort: low; }
.coding { llm_model: claude-sonnet-4-5; reasoning_effort: high; }
"
]
start [shape=Mdiamond, label="Start"]
exit [shape=Msquare, label="Exit"]
plan [label="Plan", prompt="Analyze the goal and codebase. Write a step-by-step plan.", reasoning_effort="high"]
approve [shape=hexagon, label="Approve Plan"]
implement [label="Implement", class="coding", prompt="Read plan.md and implement every step."]
simplify [label="Simplify", class="coding", prompt="Review the changes for clarity and correctness."]
start -> plan -> approve
approve -> implement [label="[A] Approve"]
approve -> plan [label="[R] Revise"]
implement -> simplify -> exit
}
```
Agents run as multi-turn LLM sessions with tool access. Human gates (`hexagon`) pause for approval. The stylesheet routes planning to a cheap model and coding to a frontier model. See the [DOT language reference](https://arc.dev/reference/dot-language) for the full syntax.
---
## 📖 Documentation
Arc ships with [comprehensive documentation](https://arc.dev) covering every feature in depth:
- [**Getting Started**](https://arc.dev/getting-started/introduction) -- Installation, first workflow, and why Arc exists
- [**Defining Workflows**](https://arc.dev/workflows/stages-and-nodes) -- Node types, transitions, variables, stylesheets, and human gates
- [**Executing Workflows**](https://arc.dev/execution/run-configuration) -- Run configuration, sandboxes, checkpoints, retros, and failure handling
- [**Tutorials**](https://arc.dev/tutorials/hello-world) -- Step-by-step guides from hello world to parallel multi-model ensembles
- [**API Reference**](https://arc.dev/api-reference/overview) -- Full OpenAPI spec with authentication, SSE events, and client SDKs
---
## Quick Start
### Install
```bash
curl -fsSL https://fabro.sh/install.sh | bash
# Initialize your project
cd my-repo/
arc init
# Run your first workflow
arc run hello
```
---
## Help or Feedback
- [Bug reports](https://github.com/brynary/arc/issues) via GitHub Issues
- [Feature requests](https://github.com/brynary/arc/issues) via GitHub Issues
- Email [bryan@qlty.sh](mailto:bryan@qlty.sh) for questions
- See [CONTRIBUTING.md](CONTRIBUTING.md) for build instructions and development workflow
---
## License
Arc is licensed under the [MIT License](LICENSE.md).
