Jujutsu MCP Server

A Model Context Protocol (MCP) server for the Jujutsu version control system. Exposes jj commands as MCP tools so AI assistants can read and manipulate jj repositories directly.

Requirements

• Node.js 26.2.0+
• jj CLI 0.4+ installed and in PATH

Installation

npm install -g jj-mcp

Or run without installing:

npx jj-mcp

Client Configuration

Add to your MCP client config. All clients use the same JSON shape:

{
  "mcpServers": {
    "jj": {
      "command": "jj-mcp"
    }
  }
}

| Client | Config file | |--------|-------------| | Claude Desktop | ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) | | Windsurf | ~/.codeium/windsurf/mcp_config.json | | Cursor | ~/.cursor/mcp.json | | Cline | MCP settings in VS Code extension |

For a local build, point command at the compiled binary instead:

{
  "mcpServers": {
    "jj": {
      "command": "node",
      "args": ["/path/to/jj-mcp/dist/index.js"]
    }
  }
}

Available Tools

Core

| Tool | Description | |------|-------------| | jj_status | Working copy status | | jj_log | Commit history (supports revset expressions) | | jj_diff | Show differences | | jj_describe | Edit commit message | | jj_commit | Create commit from working copy | | jj_new | Create new empty commit | | jj_abandon | Remove a commit | | jj_rebase | Rebase commits | | jj_squash | Combine commits | | jj_split | Split a commit | | jj_undo | Undo last operation | | jj_redo | Redo undone operation | | jj_restore | Restore files from a revision | | jj_edit | Set working copy to a revision | | jj_next | Move to next child revision | | jj_prev | Move to previous parent revision |

Bookmarks

| Tool | Description | |------|-------------| | jj_bookmark_list | List bookmarks | | jj_bookmark_create | Create bookmark | | jj_bookmark_delete | Delete bookmark |

Git Integration

| Tool | Description | |------|-------------| | jj_git_fetch | Fetch from a Git remote | | jj_git_push | Push to a Git remote | | jj_git_import | Import Git refs into jj | | jj_git_export | Export jj changes to Git | | jj_git_clone | Clone a Git repo and initialize jj |

Operations & History

| Tool | Description | |------|-------------| | jj_obslog | Obslog for a revision (mutation history) | | jj_op_log | Operation log | | jj_bisect | Binary search for regressions, e.g. jj_bisect({range: "v1.0..main"}) |

Files & Tags

| Tool | Description | |------|-------------| | jj_file_show | Show file contents at a revision | | jj_tag_list | List tags | | jj_tag_create | Create a tag |

Workspaces & Config

| Tool | Description | |------|-------------| | jj_workspace_list | List workspaces | | jj_workspace_add | Add a workspace | | jj_config_get | Get a config value | | jj_config_set | Set a config value | | jj_sparse | Manage sparse checkout patterns | | jj_init | Initialize a new jj repo | | jj_sanity_check | Verify jj is installed and repo is valid |

Available Resources

Resources provide read-only repository state without a tool call:

| URI | Description | |-----|-------------| | jj://status | Working copy status | | jj://log/recent | Recent commits (default limit: 10) | | jj://bookmarks | All bookmarks | | jj://config | Repository configuration |

All URIs accept a cwd query parameter, and jj://log/recent also accepts limit:

jj://log/recent?cwd=/path/to/repo&limit=20

Revset Expressions

All tools that accept a revset parameter support jj's revision syntax:

| Expression | Meaning | |------------|---------| | @ | Working copy | | @- | Parent of working copy | | main | Bookmark named "main" | | ::main | All ancestors of main | | main..@ | Commits between main and working copy |

Safety Features

Pre-Execution Confirmation Gate

Dangerous operations require explicit confirmation before execution. This prevents accidental data loss or repository corruption.

Affected tools: jj_abandon, jj_rebase, jj_squash, jj_split, jj_restore, jj_edit, jj_git_push, jj_git_export, jj_bookmark_delete, jj_config_set, jj_sparse (with remove)

How it works:

1. Elicitation mode (clients that support it): A confirmation dialog appears describing the risk. Accept to proceed.

2. Token fallback (all other clients): The tool returns a PRE-EXECUTION WARNING and refuses to execute. To proceed, re-call the tool with the same arguments plus confirmed: true:

   {
     "name": "jj_abandon",
     "arguments": {
       "revset": "abc123",
       "confirmed": true
     }
   }

Additional hard blocks: Some commands have mandatory safety checks that cannot be bypassed:

• jj_abandon requires a non-empty revset
• jj_rebase requires both source and destination
• jj_restore requires at least one of paths, from, or to

Troubleshooting

jj command not found — ensure jj is on your PATH:

which jj && jj --version

Verify the server:

jj-mcp --check   # checks jj is found and cwd is a jj repo
jj-mcp --version

Large output — the server uses a 10 MB buffer. For very large diffs or logs, use the limit parameter.