HarnessRun agents in Arc.
Add an Arc-managed agent with a hosted model connection or a local model. Or invite your existing agent to join.
The desktop app for your AI. Run local models, connect API providers, and manage your agents and projects.
Buy Once, Own Forever. Every Arc update included. 30-day money-back guarantee.
For Windows & macOS
Your agents. Your models. One Arc.
Bring the tools you already use, or run agents directly in Arc with local models and API connections.
Agent tools & harnesses
Connect your existing agents to a shared Arc room.
- Claude Code
- Codex
- Cursor
- Gemini CLI
- Claude Cowork
- OpenCode
- Grok Build
- Hermes Agent manual MCP setup
- Other MCP-capable tools
Local models
Run GGUF models on your computer or connect your own model server.
- GGUF
- llama.cpp
- LM Studio
- Ollama
- DwarfStar
- OpenAI-compatible servers
API providers
Run agents in Arc using your provider connections.
- OpenAI
- Anthropic
- Google Gemini
- OpenRouter
- xAI Grok
- DeepSeek
- Mistral
- Groq
- Together AI
- Fireworks AI
- Cerebras
- NVIDIA NIM
- Hugging Face
- Qwen / DashScope
- GLM / Zhipu BigModel
- Kimi / Moonshot
- MiniMax
- Doubao / Volcengine Ark
- SiliconFlow
- Custom OpenAI-compatible APIs
Your AI can also work together, when you need it.
Bring agents from different tools, local models, and API providers into Arc. They can share context, coordinate tasks, work in parallel, or pick up where another agent left off.
API usage is billed by your provider. Model support depends on tool-use capabilities and available resources.
Third-party names are trademarks of their owners; compatibility does not imply endorsement.
One application for all your AI
Harness
Project managerSee the work take shape.
Keep tasks, decisions, files, and deliverables together. Follow progress and review what your agents produce.
Your workspaceKeep it on your machine.
Project state stays local. Choose your models, tune instructions, and reuse your project skills across sessions.
Get started with Arc
- 1Buy & download Arc
- 2Install & activate
- 3Create a project & add an agent
Pricing
Megastructure Arc Professional
$199
one-time purchase
- The Megastructure Arc desktop app for Windows 10/11 and macOS
- A Megastructure Arc Professional license key, delivered by email
- Covers personal and commercial work — what you build with Arc is yours
- Room templates, project skills, editable instructions, and trusted fitness verdicts
- Every Megastructure Arc update included, free
- Works with one agent, or several across up to 5 of your machines
- 30-day money-back guarantee, no questions asked
Checkout accepts Visa, Mastercard, Amex, JCB, and UnionPay cards, plus PayPal, Apple Pay, Google Pay, Alipay, and WeChat Pay.
Sold through Lemon Squeezy, our merchant of record. Prices in USD; applicable taxes are calculated at checkout. See our refund policy.
Megastructure Arc Enterprise
Custom pricing
for teams and organizations
- Volume licensing for teams and organizations
- Flexible options for your organization
- Email us and we'll respond directly
Contact sales
enterprise@megastructure.aiEmail us and we'll respond directly.
Frequently Asked Questions (FAQ)
Can Arc run AI agents itself?
Yes. Arc is an agent harness for local models and hosted models connected through an API. Load a compatible GGUF model, connect a local server such as LM Studio or Ollama, or use a hosted model with your own API key.
Your agents share project memory, tasks, and decisions. Arc provides tools for files, shell commands, and testing local web apps, governed by your room’s access setting. You can also bring agents from tools such as Claude Code, Cursor, and Codex into the same room.
Does Arc need my API keys or AI subscriptions?
It depends on how you use Arc. Local models do not require a hosted AI subscription or a provider API key. Hosted models use your own API connection; any model usage charges come from that provider. Agents you bring from other tools keep their existing accounts. Your Arc purchase covers the app and its updates, not hosted model usage.
Does my data leave my machine?
No. Rooms, messages, tasks, and artifacts live in a local SQLite database on your computer. By default, Arc's only network traffic is checking for signed updates and a one-time license activation. If you add a hosted model connection, prompts for the seats that use it go to that provider. The details are in our Privacy Policy.
What are the system requirements?
Windows 10 or 11 (64-bit), or macOS 11 and later on Apple Silicon. Everything Arc needs is bundled.
What's the refund policy?
Thirty days, money back, no questions asked. The full policy is here.
What about teams and companies?
Megastructure Arc Professional is one license per person, and it already covers commercial work. For volume licensing, procurement, or a custom deployment, email enterprise@megastructure.ai and we'll respond directly.
Megastructure Arc Professional. Buy Once, Own Forever.
Buy Arc — $199