hcom - Claude Hook Comms

Lightweight CLI tool for real-time communication between Claude Code subagents using hooks.

🦆 What It Does

Creates a group chat where you and multiple interactive Claude Code subagents can communicate with each other across different folders on your computer. Works on Mac, Linux, and Windows with zero dependencies.

🦷 Features

• Multi-Terminal Launch - Launch Claude Code subagents in new terminals
• Live Dashboard - Real-time monitoring of all instances
• Multi-Agent Communication - Claude instances talk to each other across projects
• @Mention Targeting - Send messages to specific subagents or teams
• Zero Dependencies - Pure Python stdlib, works everywhere

🎪 Quick Start

Use Without Installing

# Launch 3 default Claude instances connected to group chat
uvx hcom open 3

# Launch researcher and code-writer from your .claude/agents
uvx hcom open researcher code-writer

# View/send messages in dashboard
uvx hcom watch

Install

# uv
uv tool install hcom
# or pip
pip install hcom
# then use with:
hcom open 3

🦐 Requirements

• Python 3.6+
• Claude Code

🗿 More Examples

# Launch 2 generic instances + 2 specific agents
hcom open 2 backend-coder frontend-coder

# Launch multiple of the same agent
hcom open reviewer reviewer reviewer  # 3 separate reviewers

# Launch agents in background with specific prompts
hcom open test-writer --claude-args "-p 'write tests for any new code'"

# Launch watchers that respond to notifications
hcom open reviewer --claude-args "-p 'review when @mentioned'"

# Pass multiple Claude flags
hcom open orchestrator --claude-args "--model claude-sonnet 
--resume session_id"

# Launch in specific directories
cd backend && hcom open api-specialist
cd ../frontend && hcom open ui-specialist

# Create named teams that can be @mentioned
cd ~/api && hcom open --prefix api debugger  # Creates api-hovoa7
cd ~/auth && hcom open --prefix auth debugger  # Creates auth-hovob8

# Message specific teams or instances
hcom send "@api login works but API fails"  # Messages all api-* instances
hcom send "@hovoa7 can you check this?"     # Message specific instance by name

🥨 Commands

Command	Description
hcom open [n]	Launch n Claude instances (or named agents)
hcom watch	Conversation/status dashboard
hcom clear	Clear and archive conversation
hcom cleanup	Remove HCOM hooks from current directory

Automation Commands

Command	Description
hcom send 'message'	Send message to chat
hcom watch --logs	View message history (non-interactive)
hcom watch --status	Show instance status (non-interactive)
hcom watch --wait [timeout]	Wait and notify for new messages

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🦖 Configuration

Configuration

Settings can be changed two ways:

Method 1: Environment variable (temporary, per-command/instance)

HCOM_INSTANCE_HINTS="always update chat with progress" hcom open nice-subagent-but-not-great-with-updates

Method 2: Config file (persistent, affects all instances)

Config File Location

~/.hcom/config.json

Setting	Default	Environment Variable	Description
wait_timeout	1800	HCOM_WAIT_TIMEOUT	How long instances wait for messages (seconds)
max_message_size	4096	HCOM_MAX_MESSAGE_SIZE	Maximum message length
max_messages_per_delivery	50	HCOM_MAX_MESSAGES_PER_DELIVERY	Messages delivered per batch
sender_name	"bigboss"	HCOM_SENDER_NAME	Your name in chat
sender_emoji	"🐳"	HCOM_SENDER_EMOJI	Your emoji icon
initial_prompt	"Say hi in chat"	HCOM_INITIAL_PROMPT	What new instances are told to do
first_use_text	"Essential, concise messages only"	HCOM_FIRST_USE_TEXT	Welcome message for instances
terminal_mode	"new_window"	HCOM_TERMINAL_MODE	How to launch terminals ("new_window", "same_terminal", "show_commands")
terminal_command	null	HCOM_TERMINAL_COMMAND	Custom terminal command (see Terminal Options)
cli_hints	""	HCOM_CLI_HINTS	Extra text added to CLI outputs
instance_hints	""	HCOM_INSTANCE_HINTS	Extra text added to instance messages
env_overrides	{}	-	Additional environment variables for Claude Code

Examples

# Change your name for one command
HCOM_SENDER_NAME="reviewer" hcom send "LGTM!"

# Make instances wait 30 minutes instead of 10
HCOM_WAIT_TIMEOUT=1800 hcom open 3

# Custom welcome message
HCOM_FIRST_USE_TEXT="Debug session for issue #123" hcom open 2

# Bigger messages
HCOM_MAX_MESSAGE_SIZE=8192 hcom send "$(cat long_report.txt)"

Status Indicators

• ◉ thinking (cyan) - Processing input
• ▷ responding (green) - Generating text response
• ▶ executing (green) - Running tools
• ◉ waiting (blue) - Waiting for messages
• ■ blocked (yellow) - Permission blocked
• ○ inactive (red) - Timed out/dead

🎲 How It Works

Hooks!

hcom adds hooks to your project directory's .claude/settings.local.json:

1. Sending: Claude agents use echo "HCOM_SEND:message" internally (you use hcom send from terminal)
2. Receiving: Other Claudes get notified via Stop hook
3. Waiting: Stop hook keeps Claude in a waiting state for new messages

• Identity: Each instance gets a unique name based on conversation UUID (e.g., "hovoa7")
• Persistence: Names persist across --resume maintaining conversation context
• Status Detection: Notification hook tracks permission requests and activity
• Agents: When you run hcom open researcher, it loads an interactive Claude session with a system prompt from .claude/agents/researcher.md (local) or ~/.claude/agents/researcher.md (global). Agents can specify model: and tools: in YAML frontmatter

Architecture

• Single conversation - All instances share one global conversation
• Opt-in participation - Only Claude Code instances launched with hcom open join the chat
• @-mention filtering - Target messages to specific instances or teams

File Structure

~/.hcom/                             
├── hcom.log       # Conversation log
├── hcom.json      # Instance tracking
└── config.json    # Configuration

your-project/  
└── .claude/
    └── settings.local.json  # hcom hooks configuration

🥔 Terminal Options

Terminal Mode

Configure terminal behavior in ~/.hcom/config.json:

• "terminal_mode": "new_window" - Opens new terminal windows (default)
• "terminal_mode": "same_terminal" - Opens in current terminal
• "terminal_mode": "show_commands" - Prints commands without executing

Default Terminals

• macOS: Terminal.app
• Linux: gnome-terminal, konsole, or xterm
• Windows: Windows Terminal / PowerShell

Running in Current Terminal

# For single instances
HCOM_TERMINAL_MODE=same_terminal hcom open

Custom Terminal Examples

Configure terminal_command in ~/.hcom/config.json to use your preferred terminal:

iTerm2

{
  "terminal_command": "osascript -e 'tell app \"iTerm2\" to create window with default profile' -e 'tell current session of current window to write text \"{env} {cmd}\"'"
}

Alacritty

{
  "terminal_command": "alacritty -e sh -c '{env} {cmd}'"
}

Kitty

{
  "terminal_command": "kitty sh -c '{env} {cmd}'"
}

WezTerm

{
  "terminal_command": "wezterm cli spawn --new-window -- sh -c '{env} {cmd}'"
}

tmux

{
  "terminal_command": "tmux new-window -n hcom sh -c '{env} {cmd}'"
}

Available Placeholders

• {cmd} - The claude command to execute
• {env} - Environment variables (pre-formatted as VAR1='value1' VAR2='value2')
• {cwd} - Current working directory

Notes

• Custom commands must exit with code 0 for success
• The {env} placeholder contains shell-quoted environment variables
• Most terminals require wrapping the command in sh -c to handle environment variables correctly

🦆 Remove

Archive Conversation / Start New

hcom clear

Remove HCOM hooks from current directory

hcom cleanup

Remove HCOM hooks from all directories

hcom cleanup --all

Remove hcom Completely

1. Remove hcom: rm /usr/local/bin/hcom (or wherever you installed hcom)
2. Remove all data: rm -rf ~/.hcom

🌮 License

MIT License

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