I accidentally gave my AI agent access to my live Payment key. Here's what I built.

While building an agent last week, I realized something uncomfortable: my agent had my live Payment API key sitting in its context window. One prompt injection attack. One malicious tool response. One leaked log file. And that key is gone. I couldn't find a clean solution, so I built one. What I built AgentGuard is a credential proxy for AI agents. Instead of giving your agent real API keys, you give it a token. When the agent makes an API call, it goes through the AgentGuard proxy which: Validates the agent token Decrypts the real credential server-side Injects it into the request Forwards to the target API Logs the call The agent never sees the real key. Ever. The code change is 3 lines Before: requests.post(" https://api.stripe.com/v1/charges ", headers={"Authorization": "Bearer sk_live_real_key..."}) After: requests.post(" https://proxy.agent-guard.dev/v1/charges ", headers={ "X-AgentGuard-Token": "your_agent_token", "X-AgentGuard-Credential": "your_credential_id" }) That's it. Bas