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Open Net Worth Docs

Use your book from other AI apps

Open Net Worth is itself an MCP server, so any AI app that speaks MCP — Claude Desktop, Claude Code, Cursor, VS Code (Copilot), ChatGPT, Cline, Continue — can connect to your book and use the same tools Lucius has: look up balances, search transactions, add and categorize them, check the budget, and so on.

This is the opposite direction from External MCP servers, where Lucius uses someone else’s server.

Before you start

  • Open Net Worth must be running whenever the other app uses it (for the desktop app, it must be open or running in the background).
  • Your API token is what lets the other app in. One exists already — you don’t create it. It lives in Settings → Security → API token, and Copy config (below) puts it into the config for you.

Set up Claude Desktop, Cursor, VS Code, Cline or Continue

These apps run on your computer, so they connect through a small bridge program that the app starts for you.

  1. In Open Net Worth, open Settings → MCP.

  2. Under Connect from…, click your app: Claude Desktop, Cursor, VS Code (Copilot) or Cline / Continue / other.

  3. If you run Open Net Worth as a server rather than the desktop app, pick how you installed it: Installed (onw) or Running from source.

  4. Click Copy config. The copy contains your real API token (the screen shows a placeholder, ONW_API_TOKEN_PASTED_ON_COPY, so the token never appears on the page).

  5. Paste it where the hint on screen says:

    AppWhere to paste
    Claude DesktopSettings → Developer → Edit Config opens claude_desktop_config.json. Paste it in (merge it into "mcpServers" if you already have other servers), save, and restart Claude Desktop.
    Cursor~/.cursor/mcp.json (all projects) or .cursor/mcp.json (one project).
    VS Code (Copilot).vscode/mcp.json (workspace) or your user mcp.json. VS Code uses "servers", not "mcpServers".
    Cline / Continue / otherThe app’s MCP settings file, in its mcpServers section.

    For Cursor, VS Code and “other”, the copied text holds two alternatives separated by // — or — lines. Paste only one of them (the stdio one, for an app on the same computer) — the comment lines and the second block would make the file invalid.

  6. Check it works: in the AI app, ask “Using open-net-worth, what’s my net worth?” It should answer with your figure. In Claude Desktop, the server also appears under its connectors/tools list.

A Claude Desktop config looks like this (server installed with onw):

{
  "mcpServers": {
    "open-net-worth": {
      "command": "/Users/you/.local/bin/onw",
      "args": ["mcp"],
      "env": {
        "ONW_BASE_URL": "http://127.0.0.1:8080",
        "ONW_API_TOKEN": "your-api-token"
      }
    }
  }
}

What the command is depends on how you installed Open Net Worth — Copy config fills in the right one:

InstallWhat the config runs
Desktop appThe Python bundled inside the app, with -m backend.cli mcp. Instead of an address, the config names your book folder (ONW_ROOT), because the desktop app picks a new address each time it starts and the bridge finds the current one there. If you move the app or switch book folders, copy the config again.
Installed (onw)The onw command, with mcp. Settings fills in its full path when it can, because apps like Claude Desktop don’t search your shell’s PATH.
Running from sourcepython3 -m backend.mcp.stdio_bridge, run in your checkout folder. See the troubleshooting note below if your app can’t start it.

Set up Claude Code

Claude Code has no tab of its own in Settings → MCP, but it takes the same configuration:

  1. In Settings → MCP, choose Claude Desktop and click Copy config.

  2. Take the part inside "open-net-worth": { … } and add it from a terminal:

    Terminal window
    claude mcp add-json open-net-worth '{"command":"/Users/you/.local/bin/onw","args":["mcp"],"env":{"ONW_BASE_URL":"http://127.0.0.1:8080","ONW_API_TOKEN":"your-api-token"}}'

    Add --scope user to make it available in every project.

  3. Check with claude mcp list — open-net-worth should show as connected — then ask Claude Code about your book.

If Open Net Worth runs as a server (not the desktop app), you can instead connect over HTTP:

Terminal window
claude mcp add --transport http open-net-worth http://127.0.0.1:8080/mcp \
  --header "Authorization: Bearer your-api-token"

Set up ChatGPT or another hosted app

Hosted apps run on their provider’s servers, so they can’t start a program on your computer or reach localhost. They connect over HTTP to <your address>/mcp with the token as a Bearer header.

  1. Make your instance reachable at a public HTTPS address first — see Exposing beyond localhost. (This needs a server install; the desktop app only accepts connections from its own computer.)
  2. Open the app through that public address, go to Settings → MCP, choose ChatGPT or Generic HTTP / remote, and click Copy config.
  3. ChatGPT: Settings → Connectors (with Developer mode on) → Add custom connector, and enter the MCP server URL (https://your-address/mcp) and the Bearer token from the copied text. Other apps: use the copied url and Authorization: Bearer … header.

What a connected app can do

An app holding your API token acts as you: it can read your whole book and make changes.

  • No approval cards. When Lucius wants to make a change that needs your approval, he shows you a card first. Other apps don’t get those cards: a tool set to Needs approval runs straight away when another app calls it. Only tools set to Blocked in Settings → Permissions are refused. If you’d rather an app couldn’t change something, block that tool.
  • Changes are recorded. Each change another app makes is logged and saved as a checkpoint, so you can undo it like one Lucius made. Things that leave the app — an email or message sent, code run — can’t be undone.
  • One token for every app. Rotating it in Settings → Security → API token → Rotate disconnects every app configured with the old one, and every installed iPhone Shortcut, at once. There’s no confirmation step. Afterwards, Copy config again and paste the new one into each app.

Troubleshooting

Claude Desktop says “Server disconnected” / the tools don’t appear

  • Open Net Worth isn’t running — start it, then restart Claude Desktop.
  • The app can’t find onw. Replace "command" with the full path printed by which onw (Windows: where onw).
  • The JSON is invalid — check you pasted only one block and didn’t leave // comment lines in.

“cannot reach Open Net Worth MCP server at …” — the bridge started but Open Net Worth isn’t running at that address. Start it. With a server install, check ONW_BASE_URL matches the address you open in your browser.

It worked, then stopped

  • You rotated the API token, or set a password for the first time (setting the first password also replaces the token). Copy the config again.
  • Desktop app: a config containing a 127.0.0.1:<port> address goes stale when the app restarts. Copy the config from inside the desktop app so it uses ONW_ROOT instead.

“Running from source” fails with No module named … — the app started your system python3, not the checkout’s environment. Change "command" to the checkout’s own onw, /path/to/open-net-worth/.venv/bin/onw (created by make setup), set "args" to ["mcp"], and remove "cwd".

“authentication required” (401) — the token in the config is wrong or old. Copy the config again.

ChatGPT can’t connect — it can’t reach localhost or a home-network address; it needs a public HTTPS address (see step 1 above).