Documentation
Open App Capability Protocol. An open standard that lets Android apps tell AI assistants what they can do.
Think of it as MCP for mobile apps. An app ships a small JSON manifest describing its capabilities. An assistant discovers that manifest at runtime, matches the user's voice to the right action, and fires a standard Android Intent. No cloud. No vendor lock-in. No special SDK from Google or Apple.
OACP is the protocol. Hark is the open-source assistant that implements it. The name means "to listen."
Try It Out
Install Hark and the Test App. Speak a command. See OACP work end-to-end in 5 minutes.
Get started ›
Add OACP to Your App
Three files. Five minutes. Your app responds to voice commands from any OACP assistant.
Add OACP ›
OACP Protocol
How discovery, invocation, parameters, and async results work under the hood.
Read the protocol ›
Hark
The open-source assistant. On-device AI, wake word, overlay UI. See how it all fits together.
Meet Hark ›
How it works
No server. No API key. Everything runs on the device.
Where to start
You want to... | Start here |
|---|---|
See it working | |
Add voice control to your app | |
Understand the protocol | |
Read the full oacp.json schema | |
Learn about Hark's architecture | |
See which apps support OACP | |
Contribute | |
Use AI to help you integrate |
Quick links
- github.com/OpenAppCapabilityProtocol/oacp - Protocol spec
- github.com/OpenAppCapabilityProtocol/oacp-android-sdk - Android SDK
- github.com/OpenAppCapabilityProtocol/hark - Hark assistant
- github.com/OpenAppCapabilityProtocol - Organization