VrChat docs state it’s possible but there is no description of how.
New to contacts, I understand the theory and can test phys-bones but cannot find a description of how to test without building the avatar.
What you’ll need to do is set your Avatars animation controller to the controller that has the logic for your receiver. So, the FX controller more than likely.
Then you can create a new object in your scene - a sphere works well for testing - and add a contact sender to it.
When you then run your game inside Unity, switch from the Game tab to your Scene tab and then you can move your test object to collide with your receiver.
Here’s a link to a great vid that explains a lot of this stuff:
Also - by adding animation controllers to your avatar and playing in your scene, you can do some debugging of animations and the like as well.
Thank you for the detailed description!
Would be nice to see the docs updated with this kind of info in the future.
But one can dream 
1 Like
Just don’t forget to remove that animation controller before you publish your avatar!