Arcade is a tools & integrations option for building AI agents. Tool-calling with per-user OAuth, so the agent acts as the user, not as root.
Worth knowing. The per-user token model is what stops one user's agent reading another user's mailbox.
ARCADE_API_KEY=
| Option | What it does | Licence | Self-host |
|---|---|---|---|
| Arcade | Tool-calling with per-user OAuth, so the agent acts as the user, not as root. | Open source | Yes |
| MCP (Model Context Protocol) | The open protocol for exposing tools and data to agents. The default answer. | Open source | Yes |
| Composio | Managed auth and tool-calling for 250+ SaaS apps. | Open source | No |
| Browserbase | Managed headless browsers with stealth and session replay, plus Stagehand. | Proprietary | No |
| Playwright MCP | Drive a real local browser over MCP, using the accessibility tree. | Open source | Yes |
| Nango | Open-source integration platform — you own the OAuth and the sync logic. | Open source | Yes |
Every page here answers to Accept: text/markdown and returns the same content at roughly a tenth the tokens. No separate site, no toggle — same URL.
curl -s -H "Accept: text/markdown" https://newagent.build/c/arcade