Fichero Toolbox
Connect AI tools — Claude Code, Claude Desktop, Gemini, Codex, and others — to your Mac apps, with multiple clients at the same time.
What it does
Tinderbox's built-in MCP server accepts one connection at a time. A second client drops the first. If you run Claude Desktop and Claude Code together, or run multiple agents in parallel, only one can talk to Tinderbox — until you quit the other.
Fichero Toolbox sits between your AI clients and Tinderbox and multiplexes the connection. Any number of clients can work with the same Tinderbox document simultaneously, without conflict.
It also adds helper tools for navigation, window management, export, and app lifecycle control — things Tinderbox's native MCP server doesn't expose.
Claude Code ──┐
├──→ Fichero Toolbox ──→ Tinderbox
Claude Desktop┘
Tools
All Tinderbox native operations pass through: get_notes, set_value, create_note, create_link, delete_note, get_document, set_document, do, evaluate.
Additional tools:
- tbx_nav — Navigate to notes, set views, build note URLs
- tbx_doc — Open and close documents, manage windows
- tbx_app — Start, restart, and quit Tinderbox
Download
Version 0.0.1 — March 2026
Requires macOS 14 (Sonoma) or later and Tinderbox 11.
Open the DMG, drag Fichero Toolbox to Applications, and launch it. The app lives in your menu bar and manages the connection automatically.
Connect an AI client
Claude Code — use the app's Clients tab, or run:
claude mcp add-json --scope local tinderbox '{
"command": "/Applications/Fichero Toolbox.app/Contents/Resources/FicheroToolboxDaemon",
"args": ["--client"]
}'
Claude Desktop — use the app's Clients tab, or add to ~/Library/Application Support/Claude/claude_desktop_config.json:
{
"mcpServers": {
"tinderbox": {
"command": "/Applications/Fichero Toolbox.app/Contents/Resources/FicheroToolboxDaemon",
"args": ["--client"]
}
}
}
Codex CLI, Google Gemini CLI — use the app's Clients tab. The app installs the configuration automatically.
How it works
Fichero Toolbox has two components: a menu bar app and a background daemon. The app is your control point — it starts, stops, and monitors the daemon, and shows status in the menu bar. The daemon is the actual server that handles all MCP traffic.
The daemon
The daemon is a Swift process managed by launchd, Apple's system service manager. It starts when you launch the app and stops when you quit it. It runs as your user — no administrator privileges required.
The daemon opens a Unix domain socket (~/Library/Application Support/FicheroToolbox/daemon.sock, permissions 0600 — owner-only). AI clients connect to this socket. The daemon accepts any number of simultaneous connections, queuing and routing requests independently for each client.
MCP multiplexing
Each AI client (Claude Code, Claude Desktop, Codex, Gemini, etc.) spawns a separate instance of the daemon binary in client mode (--client). That client process speaks the MCP protocol on stdio to the AI tool, and forwards requests over the Unix socket to the main daemon. The daemon serialises requests to Tinderbox's own MCP server, collects responses, and routes them back to the correct client. From each AI tool's perspective it has a dedicated MCP connection; from Tinderbox's perspective there is exactly one.
App↔daemon communication
The menu bar app communicates with the running daemon over a separate authenticated XPC Mach service (com.ficherotoolbox.daemon.admin). This channel is used for health checks, settings, and control operations. It requires that the app and daemon share the same code-signing team identity — a macOS security guarantee that prevents other processes from impersonating the admin channel.
Tinderbox connection
Fichero Toolbox connects to Tinderbox's built-in MCP server over a local socket that Tinderbox exposes when it is running. Native Tinderbox operations (get_notes, set_value, create_note, etc.) are forwarded directly. Additional operations (tbx_nav, tbx_doc, tbx_export) use AppleScript, bypassing the MCP layer entirely to access parts of Tinderbox that its MCP server does not expose.
AI tool (Claude Code)
│ stdio / MCP
▼
FicheroToolboxDaemon --client
│ Unix socket (0600)
▼
FicheroToolboxDaemon (main)
├──→ Tinderbox MCP socket (native passthrough tools)
└──→ AppleScript / OSA (nav, doc, export tools)
Security
- Unix socket is owner-only (0600) — no other user or process can connect
- Admin XPC channel requires matching code-signing team identity
- All input is validated and size-limited before reaching Tinderbox
- Rate limiting and request queue limits are enforced per client
- Nothing is exposed to the network — all communication is local
Frequently Asked Questions
What problem does this solve?
Tinderbox's MCP server drops existing connections when a second client connects. Fichero Toolbox eliminates that constraint — any number of clients can share the same session.
Does Tinderbox need to be open?
Yes. Fichero Toolbox connects to Tinderbox's built-in MCP server. Tinderbox must be running.
What AI clients does it support?
Any MCP client: Claude Desktop, Claude Code, Codex CLI, Gemini CLI, or anything that speaks the Model Context Protocol.
How do I start and stop the service?
Open Fichero Toolbox from your Applications folder. It lives in the menu bar — click the icon to start, stop, or restart the bridge service. Quitting the app stops the service.
Where are the logs?
~/Library/Logs/FicheroToolbox/
Is it secure?
The connection uses a Unix socket with owner-only permissions. Nothing is exposed to the network. All traffic stays on your Mac.
Is it free?
Fichero Toolbox is free during early development.
What is MCP?
The Model Context Protocol is an open standard for connecting AI assistants to external tools. It lets AI clients like Claude interact with your applications in a structured, controlled way.
What does "Fichero" mean?
Fichero is Spanish for card-file cabinet — the physical index card systems long used by researchers and archivists, and the method behind Niklas Luhmann's Zettelkasten. The name connects that tradition to modern AI-assisted knowledge work.
About
Fichero Toolbox is made by Daniel Tubb, an Associate Professor of Anthropology at the University of New Brunswick. It was vibe coded with Claude Code and Codex.