mcacp — Claude Code MCP server: what it does, how to install
Connects MCP clients to ACP coding agents from one chat. Use it to run agents side by side, build handoffs, and resume saved sessions.
claude mcp add mcacp -- npx -y mcacpWhat mcacp does
mcacp acts as an MCP-to-ACP bridge over stdio. From Claude Code, Zed, or another compatible client, you can start an agent, create a session, send prompts, read events, and stop the process. It can also search the ACP registry, install agents, discover configured agents, and check upgrades.
The server exposes 22 tools grouped around registry actions, lifecycle control, sessions, interaction, and status. Sessions persist on disk and can be reopened with load_session; each session accepts allow_all, deny_all, elicit, or operator permissions. In Claude Code, permission requests use operator because this host does not support MCP elicitation. Add the server with claude mcp add mcacp -- npx -y mcacp.
What it helps with
- run ACP coding agents from an MCP client
- compare several agents on the same task
- chain coding, review, and test sessions
- resume an agent session saved on disk
- handle agent tool permissions interactively
Example prompts for the agent
- Search the ACP registry and install Gemini using
registry_searchandagent_install. - Initialize Codex, create a session for the current directory, and ask it to refactor authentication.
- Load a saved session with
load_sessionand show its current events.
How to install mcacp
Platform CLI
claude mcp add mcacp -- npx -y mcacpPlatform CLI
codex mcp add mcacp -- npx -y mcacpConfig file
{
"mcpServers": {
"mcacp": {
"command": "npx",
"args": [
"-y",
"mcacp"
]
}
}
}Config file
{
"servers": {
"mcacp": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"mcacp"
]
}
}
}Platform CLI
gemini mcp add mcacp npx -y mcacpStep by step, with commands for each platform: How to add an MCP server to Claude Code, Codex, Cursor, VS Code, Gemini CLI and more
Questions about mcacp
How do I install mcacp in Claude Code?
Run claude mcp add mcacp -- npx -y mcacp.
What does mcacp do?
It lets an MCP client start and control ACP coding agents, manage sessions, send prompts, receive events, install agents, and handle permissions.
How are permissions handled in Claude Code?
Claude Code uses operator mode for permission requests because it does not support MCP elicitation. The host agent resolves them through grant_permission.
