# Shell installer for macOS, Linux, Android (Termux), and WSL
curl -fsSL https://github.com/aannoo/hcom/releases/latest/download/hcom-installer.sh | sh
Message each other in real-time, bundle context for handoffs.
Observe each other: transcripts, file edits, terminal screens, command history.
Subscribe to each other: notify on status changes, file edits, specific events. React automatically.
Spawn, fork, resume, kill each other, in any terminal emulator.
How it works
Hooks record activity to a local SQLite database and deliver messages from it.
agent → hooks → db → hooks → other agent
For Claude Code, Gemini CLI, Codex, and OpenCode, messages arrive mid-turn (injected between tool calls) or wake idle agents immediately. Any other AI tool can join by running hcom start. Any process can wake agents with hcom send.
Collision detection is on by default: if two agents edit the same file within 30 seconds, both get notified.
Hooks go into config dirs under ~/ (or HCOM_DIR) on first run. If you aren't using hcom, the hooks do nothing.
Terminal
Every agent runs in a real terminal you can see, scroll, and interrupt. Any emulator works for spawning; kitty, wezterm, and tmux additionally support closing panes from hcom kill.
To configure a custom terminal open/close setup, tell agent to run:
hcom config terminal --info
Cross-device
Connect agents across machines via MQTT relay.
hcom relay new # get token
hcom relay connect <token> # on each device
Relay payloads are end-to-end encrypted. Brokers do not see data.
Treat the join token like an SSH key or API key.
If the token may have leaked, run hcom relay off --all to disconnect all devices.
Use a private/custom/self-hosted broker with --broker and --password for better security.
Security model
hcom relay is one trust domain for one operator's devices. Membership is all-or-nothing. There are no scoped roles, read-only peers, or per-device permissions.
Relay payloads use a shared PSK with XChaCha20-Poly1305. The encryption binds each payload to the relay, topic, and timestamp. A replay guard drops duplicate envelopes inside a freshness window.
Brokers and network observers cannot read or forge payloads without the PSK. They can still see metadata: topic names, timing, message sizes, and connection patterns.
What the token means
The join token contains the relay ID, broker URL, and raw PSK. hcom does not ask a server to validate it. It has no expiry, no scope, and no revocation list.
On public brokers, a leaked token gives an attacker full control of the relay. They can decrypt captured traffic, publish authenticated relay traffic, send text to listening agents, launch agents on enrolled devices, kill running agents, and use remote relay RPCs. If those agents can run tools, treat that as shell access on every enrolled device in the relay.
On private brokers with --password, the token still leaks the PSK, so captured traffic is still exposed. But the token alone is not enough to publish unless the attacker also has the broker password. Use a private broker when broker-side access control matters, or when the metadata shape of your traffic is itself sensitive. --password is broker access control, not another layer of message encryption.
Limits by design
Forward secrecy. A leaked PSK can decrypt old captured traffic.
Per-device attribution inside a relay. Sender identity is routing metadata, not authorization. Every enrolled device speaks with full authority.
Prompt injection from an authenticated peer. Enrollment is total trust — a peer can launch, kill, and drive agents via RPC, not just send messages. Only enroll devices you would give shell access to.
Local OS compromise. hcom trusts the local user account and ~/.hcom/config.toml. It does not defend against another user on the same account or malware with filesystem access.
Storage
The PSK is stored in ~/.hcom/config.toml. On Unix, hcom writes that file with mode 0600.
hcom keeps the PSK out of environment variables. Remote config_get and config_set refuse relay_psk, relay_token, relay_id, and the broker URL. hcom relay status shows only a short fingerprint so two devices can verify they share the same key without printing it.
Anyone who can read that file — another user on the same OS account, malware, or a backup written without preserving permissions — has the full PSK.
Incident response
Run hcom relay off --all. It asks every reachable trusted peer to disable the relay, then disables it locally, so your agents stop acting on attacker messages. It is best-effort damage control, not containment: the attacker's device ignores the request.
The PSK cannot be revoked. There is no server to notify and no denylist to update. Anyone who has the PSK can keep using the old relay until you stop using it.
To keep using relay after a leak, create a new relay with hcom relay new and move every trusted device to the new token. Rotation also changes the relay_id, so retained state on the old broker topics is orphaned.
Troubleshoot
hcom status # diagnostics
hcom reset all # clear and archive: database + hooks + config
hcom run docs # tell agent to run
hcom r <session_id> # Resume a session started outside hcom
hcom f <session_id> # Fork a session in hcom
Claude Code headless and subagents
Detached background processes in print mode stay alive. Manage through the TUI.
hcom claude -p 'say hi in hcom'
For subagents, run hcom claude, then prompt:
run 2x task tool and get them to talk to each other in hcom
CLI commands
What you might type from a shell. Agents run their own commands that they learn from the hcom CLI primer (~700 tokens) at launch. hcom <command> --help for full flags.
Spawn
hcom [N] claude|gemini|codex|opencode # launch N agents
hcom r <name|session_id> # resume agent
hcom f <name|session_id> # fork session
hcom kill <name|tag:T|all> # kill + close terminal pane
hcom launch flags:
| Flag | Purpose |
|---|---|
| --tag <name> | Group label — agents can be addressed as @tag |
| --terminal <preset> | Where windows open: default (auto-detect), kitty, wezterm, tmux, cmux, iterm, etc… |
| --dir <path> | Directory where the agent launches |
| --headless | Run in background with no terminal window |
| --device <name> | Spawn on a remote device (via relay) |
| --hcom-prompt <text> | Initial user prompt |
| --hcom-system-prompt <text> | Append to system prompt |
Anything else is forwarded to the tool: --model sonnet, --yolo, etc.
Other commands
hcom # TUI dashboard
hcom send -b @luna -- hey # one-off message to an agent
hcom list # show all active agents
hcom term [name] # view/inject into an agent's PTY screen
hcom events --wait <filters> # Block until match for scripting
hcom update # update hcom version
hcom config # show all values with sources
hcom config <key> # get
hcom config <key> <value> # set
hcom config <key> --info # detailed help for a key
hcom config -i <name> <key> <value> # per-agent override at runtime
Keys
| Key | Purpose |
|---|---|
| tag | Group label — launched agents become tag-name |
| hints | Text appended to every message the agent receives |
| notes | Text appended to bootstrap (one-time, at launch) |
| `a
The agent harness performance optimization system. Skills, instincts, memory, security, and research-first development for Claude Code, Codex, Opencode, Cursor and beyond.
