Try It Out
OACP is early. Most apps don't support it yet. The Test App is a playground built specifically for trying OACP with Hark. Install both, speak a command, see it work. Five minutes.
What you need
- An Android device running Android 8.0 (API 26) or higher
- About 5 minutes for setup, plus ~2 minutes for Hark's first-launch model download
1. Install Hark
Download the latest APK from GitHub Releases and sideload it.
2. Install the OACP Test App
Download the latest APK from GitHub Releases. Or clone the repo and build it yourself.
3. Set Hark as the default assistant
- Open Settings on your device
- Go to Apps → Default apps → Digital assistant app
- Select Hark
This lets you launch Hark by long-pressing the Home button, just like Google Assistant.
4. Try your first command
Long-press the Home button. Hark opens and listens. Say:
"increment the counter"
The Test App opens and the counter goes up by one. That's OACP working end to end.
5. Try more commands
Say this | What happens |
|---|---|
"increment the counter by 5" | Counter goes up by 5 |
"what's the battery level" | Hark reads back battery percentage (no app opens) |
"reset the counter" | Counter resets to zero |
"set the counter to 42" | Counter jumps to 42 |
What just happened
Here is the full chain, all running on your device:
- Voice capture - Hark recorded your speech and transcribed it on-device (Whisper)
- Discovery - Hark queried every installed app for an
oacp.jsonmanifest via Android ContentProviders - Intent resolution - EmbeddingGemma matched your utterance to the right capability from all discovered capabilities
- Parameter extraction - Qwen3 pulled structured parameters from your sentence ("5", "42", etc.)
- Dispatch - Hark fired an Android broadcast Intent with the action and parameters. The Test App's receiver handled it.
No cloud. No API key. No account. Everything ran locally on the device.
For developers: test with adb
You don't need to use your voice every time. Send commands directly via adb:
This is the same mechanism Hark uses. The broadcast actions and extras match what the Test App declares in its oacp.json.
Troubleshooting
Nothing happens when I long-press Home
Hark is not set as the default assistant. Go to Settings → Apps → Default apps → Digital assistant app and select Hark.
Hark says it can't find any apps
The Test App is not installed, or it was installed after Hark's last discovery scan. Reinstall the Test App and try again.
First command is slow
Hark downloads AI models on first launch. This takes about 2 minutes depending on your connection. Subsequent launches are fast.
Hark opens but doesn't hear me
Check that Hark has microphone permission. Go to Settings → Apps → Hark → Permissions → Microphone.
The more apps that adopt OACP, the more useful Hark becomes. That's where you come in. Add OACP to your app →