ACP Runners: From Text Pipes to Agent Protocols
In the previous blog post, we introduced CLI Runners — a way to use your existing AI subscriptions (Claude Pro, Copilot, Gemini, etc.) directly inside IntelliJ by piping prompts to external CLI tools. CLI Runners solved the "double-paying" problem, but they communicate through plain text over stdin/stdout. That works, but it's a bit like having a conversation by passing notes under a door.
ACP Runners open that door. Instead of unstructured text, they use the Agent Communication Protocol — a structured, bidirectional communication layer built on JSON-RPC 2.0 — to turn your IDE into a proper agent hub.
