We Need to Talk About ACP
Not enough folks are talking about Agent Client Protocol. ACP allows apps to integrate once for all the various LLM agent CLIs so users can pick their UI for their agent of choice.
ACP is unique because it allows usage of LLM lab subscriptions outside of the tools provided by each LLM provider. Gemini CLI, Claude Code, and OpenAI Codex CLIs each expose their functionality to the outside world each in their own unique sanctioned way. This is the first time LLM providers are allowing 3rd party clients to access their APIs delegating payment to the user via subscription. It's also extensible, so covering new agent functionality should be possible.
Think of ACP like a LiteLLM, OpenRouter, or Vercel AI sdk, but for agents. It was created (and so graciously shared) by the folks over at Zed Industries to allow for agent integration between Zed and Gemini CLI, Claude Code & other agentic coding CLI tools.
Some 3rd party agent tools make direct calls to the APIs that Claude Code uses, with mixed success. It seems that Anthropic enforces the Claude Code system prompt when credentialed with Claude Code, but the Claude Code SDK (which was recently updated to cover more of Claude Code's unique features) is free game for 3rd party integrators. Using the Claude Code SDK directly does have benefits, as it takes time & effort to wrap the functionality of Claude Code in an ACP Server so there may be more limited functionality with more delay compared to using the SDK directly. Surely similar goes for other agents as well.
While it's still early days for ACP, it's very usable inside Zed with both Gemini and Claude Code supported today. Gemini CLI has native ACP support. The Zed team built an ACP wrapper for Claude Code and there seems to be one in the works for OpenAI Codex as well. The Zed team moves fast, so it should be any day now.
I hope we see more people wrapping these tools; I hope people just like you and I build interfaces for the next generation of programming. Agents are democratized, Claudemmoditized even. My favorite tool in the space is Conductor to run background doing agents locally instead of remotely. Another very large AI IDE company cloned their interface, so that's validation it's possible to build unique interfaces as a small maker.
I hope I've filled you in enough on the space enough to talk about the SQL-oriented ACP client that I've been working on. Sidequery supports ACP in a native Mac app because you shouldn't need another subscription to use AI features in your data tools. Bring your own agent, as long as it supports ACP.
