Zinc Is Not Cowork

Agent multiplexer for the terminal

Manage AI coding agents as persistent background daemons. Attach, detach, and switch between agent sessions instantly. Think tmux, but purpose-built for AI coding agents.

Requires Linux or macOS. zinc uses Unix PTYs and is not available on Windows.

Why not tmux?

You can run agents in tmux panes. zinc adds three things tmux can't do:

1. State awareness — zinc knows whether an agent is working, waiting for input, or blocked on a permission prompt. tmux just shows you a pane with text.
2. Session resume — zinc integrates with agent session history, letting you resume previous conversations. tmux doesn't know what's running inside it.
3. Structured lifecycle — spawn, kill, and list agents by ID across directories. No manual pane/window management.

If you run one agent at a time, tmux is fine. zinc shines when you're running 3+ agents across worktrees and need to know which ones need you.

Features

• Never lose a session - agents run as background daemons, survive terminal close
• TUI supervisor - full-screen view of all agents, keyboard-driven
• Instant switching - one keystroke to attach/detach from any agent
• State tracking - see at a glance which agents are working, waiting for input, or blocked
• Session picker - resume previous sessions or start fresh, with automatic session discovery
• Composable - works with any worktree/project workflow (designed to pair with yawn)

Quick start

cargo install zinc-cli

# Set up Claude Code hooks for accurate state detection
zinc init --agent claude

# Spawn a Claude agent in your project
cd ~/projects/myapp
zinc spawn

# Or spawn with a prompt and attach immediately
zinc spawn -A "fix the failing auth tests"

# Attach (resolves from current directory)
zinc attach

# Open the TUI to see all agents
zinc

TUI

Running zinc with no arguments opens the interactive supervisor:

 zinc -3 agents (1 needs input)
  STATE     AGENT      ID              DIRECTORY                          UPTIME
  ● work    claude     fix-auth        ~/worktrees/myapp--fix-auth          12m
▸ ▲ input   claude     fix-nav         ~/worktrees/myapp--fix-nav            8m
  ● work    claude     fix-api         ~/worktrees/myapp--fix-api            3m
 enter:attach  n:new  d:kill  q:quit

• j/k or arrows to navigate
• enter to attach to the selected agent
• n to spawn a new agent
• d to kill the selected agent
• p to toggle scrollback preview
• / to filter agents by ID, provider, or directory
• q to quit (agents keep running)

When attached, a status bar shows the agent info. ctrl-] detaches back to the list.

CLI commands

zinc                              # open TUI
zinc spawn [prompt] [options]     # launch a new agent
zinc attach [id]                  # attach to an agent (resolves from CWD if omitted)
zinc list [--json]                # list all agents and their states
zinc kill [id]                    # stop an agent (resolves from CWD if omitted)
zinc init --agent <name>          # configure agent hooks for state detection
zinc shutdown                     # stop all agents and the daemon
zinc status                       # check if the daemon is running

zinc spawn

zinc spawn                                    # shows session picker if sessions exist
zinc spawn "fix the bug"                      # start with a prompt
zinc spawn -A "fix the bug"                   # spawn and attach immediately
zinc spawn --new                              # skip session picker, always start fresh
zinc spawn --new "fix the bug"                # new session with a prompt
zinc spawn --agent codex --dir ~/project      # explicit agent and directory

Arguments:

• <prompt> - initial prompt text (positional, optional)

Flags:

• -a/--agent <name> - provider to use (default: from config, or claude)
• -d/--dir <path> - working directory (default: current directory)
• -i/--id <name> - agent ID (default: derived from directory name)
• -n/--new - skip session picker, always start a new session
• -A/--attach - attach to the agent immediately after spawning

zinc attach

zinc attach fix-auth              # attach by ID
zinc attach                       # attach to the agent in current directory

When no ID is given, zinc finds the agent running in your current directory. Errors clearly if there are zero or multiple agents.

zinc kill

zinc kill fix-auth                # kill by ID
zinc kill                         # kill the agent in current directory

Same CWD resolution as zinc attach.

zinc init

zinc init --agent claude          # configure Claude Code hooks

Sets up agent hooks for accurate state detection. For Claude Code, this writes hook entries to ~/.claude/settings.json so zinc can distinguish between working, input, and blocked states. Without this, zinc falls back to PTY activity heuristics.

State detection

zinc uses layered detection to track what each agent is doing:

State	Meaning
working	Actively producing output
blocked	Needs user action (e.g. permission prompt)
input	Waiting for new user prompt
idle	Running but inactive

For Claude Code, state is detected via hooks (immediate, distinguishes input from blocked). For other agents, PTY activity heuristics are used as a fallback.

Configuration

~/.config/zinc/config.toml - all fields optional:

[spawn]
default_agent = "claude"               # default provider (alias: agent)
namer = "yawn prettify {dir}"          # derive agent ID from directory

[daemon]
scrollback = 1048576                   # scrollback buffer size in bytes (1MB)

[notify]
command = "notify-send 'zinc: {id}' '{state}'"   # command to run on state change
on_states = ["input", "blocked"]                  # which states trigger (default)

Custom TUI commands

[[tui.commands]]
name = "open in editor"
key = "o"
command = "code {dir}"

Adds a keybinding to the TUI that runs a shell command for the selected agent. Placeholders: {id}, {dir}, {provider}. Reserved keys (q, j, k, n, p, d, /) cannot be used.

Project picker

[spawn]
project_picker = "yawn list"                  # command that outputs project names, one per line
project_resolver = "yawn resolve {name}"      # resolves a name to a directory path

When configured, pressing n in the TUI shows a project picker before spawning. The picker lists items from project_picker output. If project_resolver is set, the selected item is resolved to a directory path; otherwise, items are treated as paths directly.

Notifications

The notify.command field runs a command when an agent transitions to a matching state. Placeholders {id}, {state}, {old_state} are shell-quoted and substituted.

# Linux (libnotify)
command = "notify-send 'zinc: {id}' '{state}'"

# macOS
command = "osascript -e 'display notification \"{state}\" with title \"zinc: {id}\"'"

Namer

The spawn.namer field runs a command to derive the agent ID from the directory. {dir} is replaced with the shell-quoted path:

namer = "basename {dir}"               # use directory name as-is
namer = "yawn prettify {dir}"          # use yawn for clean names

Fallback chain: --id flag > namer > directory basename.

Composing with other tools

zinc operates on directories, so it composes naturally with any worktree or project manager. See yawn for an example of worktree-based workflows with zinc.

Architecture

zinc uses a daemon-client architecture (like tmux):

• zinc daemon - long-running daemon that owns agent PTYs, tracks state, broadcasts events
• zinc - short-lived client that connects to the daemon via Unix socket

The daemon starts automatically on first zinc command and shuts down automatically after 30 seconds of inactivity (no agents, no connected clients). It keeps agents alive independently of any terminal.

Install

From source

cargo install zinc-cli

GitHub Releases

Download binaries from the releases page.

Nix flake

inputs.zinc.url = "github:ComeBertrand/zinc";

# then in your packages:
inputs.zinc.packages.${system}.default

Shell completion & man page

Shell completions are generated at build time:

# Bash
cp completions/zinc.bash ~/.local/share/bash-completion/completions/zinc

# Zsh (or place it anywhere in your $fpath)
cp completions/_zinc ~/.local/share/zsh/site-functions/_zinc

# Fish
cp completions/zinc.fish ~/.config/fish/completions/zinc.fish

A man page is generated at build time:

man target/*/build/zinc-cli-*/out/man/zinc.1

License

MIT