How OpenACP talks to 28+ AI agents through one protocol — architecture of a self-hosted messaging bridge

I needed Claude Code to talk to Telegram. Not a chatbot — the actual coding agent, running on my machine, reading my files, writing code. I wanted to send it a task from my phone and get structured updates back, including permission prompts I could approve with a tap. Parsing terminal stdout wasn't going to cut it. I tried that approach early on and it kept breaking whenever the agent's output format changed. That's when I found OpenACP and started contributing. What made it work where my hacky approach didn't was a protocol layer underneath: the Agent Client Protocol (ACP), an open standard that lets any client communicate with any compatible coding agent through structured JSON-RPC messages. Here's how the architecture works. The problem: agents live in your terminal AI coding agents — Claude Code, Gemini CLI, Codex, and others — are powerful but they assume you're sitting at a terminal. Leave your desk and the agent hits a permission prompt? It waits. You come back 40 minutes later