IDE via ACP

4.5. IDE via ACP — Direct Integration into the Code Editor

What ACP is, and why it matters

The Agent Client Protocol (ACP) is an open standard initiated by Zed, co-developed with JetBrains, with participation from Anthropic, OpenAI, Google, and GitHub — playing the same role as the Language Server Protocol (LSP), but for AI agents instead of programming languages. An agent that supports ACP runs in any editor that supports ACP, with no per-editor integration needed.

How to start Hermes in ACP mode

hermes acp

This command starts Hermes as an ACP stdio server — the editor (Zed, JetBrains, Neovim…) spawns Hermes as a subprocess and talks to it over JSON-RPC 2.0 on stdin/stdout.

Editor-side configuration (Zed example)

{
  "agent_servers": {
    "Hermes": {
      "command": "hermes",
      "args": ["acp"]
    }
  }
}

Synergy with MCP

ACP is designed to be MCP-friendly — the editor can pass MCP server configuration straight through to the agent, and since Hermes already knows how to use MCP (11.1), combining the two standards flows seamlessly, with no dedicated translation layer.

Notes

• ACP does not replace the CLI or the gateway — it is a third parallel interface mode; you pick whichever fits the working context of the moment, with no need to “switch over” to ACP entirely.
• Because Hermes is already registered in the ACP Registry, the agent shows up ready in the agent picker of supporting editors, with no extra configuration beyond installing Hermes.
• For editors that use Zed-like JSON configuration (JetBrains, Neovim plugins such as CodeCompanion.nvim), the configuration template is nearly identical — only the location of the settings file differs.