MCACP is a ready MCP-to-Agent Client Protocol bridge with concurrent agents, asynchronous prompts, stored sessions and permission decisions returned to the host agent. OMP can be registered by launch command; Hermes + MCACP + OMP still needs a compatibility test.

MCACP is a ready-made candidate for Hermes controlling external ACP workers. Its README documents process lifecycle, parallel sessions, asynchronous prompting, event polling, cancellation, stored sessions and reload.

The operator permission policy returns requests to the calling agent, which answers through grant_permission. This matches Hermes deciding routine requests and escalating only what it cannot decide. The escalation rule remains Hermes' instruction, not something this permission mode guarantees.

MCACP's configuration accepts a fixed executable and arguments per agent. OMP documents omp acp. Combining those interfaces gives this candidate registration:

{
  "defaultPermissionPolicy": "operator",
  "agent_servers": {
    "omp": {
      "command": "omp",
      "args": ["acp"],
      "permissionPolicy": "operator"
    }
  }
}

This is an inferred configuration, not a tested Hermes/OMP integration. Resuming an actual conversation depends on the worker's ACP session-loading support. MCACP stores sessions on disk; that is different from Cloudflare Durable Object execution.

Give Hermes only the necessary agent-control tools and keep worker registration outside its writable scope. Exclude installation and configuration-management tools when the intended authority is only delegation.

The smaller theorionic/mcp-acp-bridge also documents concurrent connections, polling and manual approvals. Its README does not document restart persistence or a configurable OMP registration.

The similarly named i-am-bee/acp-mcp implements Agent Communication Protocol, a different ACP from OMP's Agent Client Protocol.

Sources: MCACP, Configuration, OMP CLI, Agent Communication Protocol adapter.