The AP3 Playground is best on desktop — the inspector tabs are dense JSON and don’t fit a phone screen.
AP3 Playground
Watch two agents check for shared data — without revealing the data.
What is AP3?
AP3 is a protocol for two agents to compute over each other's private data without revealing the data itself. This playground demonstrates the canonical example — Private Set Intersection (PSI), where one side learns whether a record matches, but never which record matched.
Scenario: Bank A has a new customer. Bank B maintains a sanctions list. Bank A wants to know if its customer is on Bank B's list — without sending the customer's identity to Bank B, and without Bank B handing over its full list. PSI is the cryptographic tool that makes this exchange possible.
Playground servers
Initiator agent
A2A URL
http://127.0.0.1:18082
AgentCard endpoint
/.well-known/agent-card.json
Acts as the AP3 initiator and opens the protocol by sending the first envelope (phase init).
Receiver agent
A2A URL
http://127.0.0.1:18083
AgentCard endpoint
/.well-known/agent-card.json
Validates the intent + envelope (session binding, signature, participants, payload hash, replay) and responds.
The playground UI talks to these agents and captures A2A HTTP to populate the Inspector.
Flow
  1. Discovery: read AgentCards + AP3 extension (roles, ops, commitments, public key)
  2. Compatibility: score + explanation (why compatible / incompatible)
  3. Protocol run: execute PSI over A2A JSON-RPC
  4. Inspector: view request, HTTP trace, envelopes, directives, audit checks, logs
Why a playground
Privacy claims are easy to make and hard to verify. This playground is glass-box: every envelope on the wire, every signature, every receiver-side check is exposed in the inspector. You can also tamper with messages or replay them to see the defenses fire in real time — so you can trust the protocol because you watched it work, not because we said so.
AP3 Playground
Start with Compatibility Lab, then inspect protocol runs.
Compatibility Lab
Initiator
Receiver
Computing compatibility…
AgentCards (preview)
Initiator AgentCard JSON

              

              

                
Receiver AgentCard JSON

                

              

            

          


          

            
          

        

      

    


    
    

      

        

          

            

              
AP3 Playground

              
Inspector + Playground

            

            

              
            

          


          

            

              
Walkthrough

              

              

                
PSI outcome

                

                  
                  
                

                

                  Attacks
                  
                

                

                  
                  
                

                

                  
                  
                

              

              

              

                
                
                
                
                
              

              
Not started.