harmonyhub-py 0.2.0

Local control of the Logitech Harmony Hub: library, CLI, and MCP server

harmonyhub-py

Local control of the Logitech Harmony Hub from Python — usable as a library, a CLI, and an MCP server.

The library talks to the hub on the local network only (port 8088 over WebSocket). No Logitech cloud round-trip is required after the one-time provisioning POST that the hub itself answers locally.

Installation

uv sync                          # uv-managed checkout (recommended; uses .venv.mac)
pip install -e .                 # or plain pip from the repo root
pip install -e .[dev]            # plus ruff / mypy / pytest

Python ≥ 3.14 is required (declared in pyproject.toml; matches the pinned interpreter in uv.lock and .python-version).

Quick start (library)

import asyncio
from harmonyhub import HarmonyHubClient


async def main() -> None:
    async with HarmonyHubClient("192.168.178.50") as hub:
        info = await hub.get_info()
        print(f"Hub: {info.friendly_name} (remote-id: {info.remote_id})")

        for activity in await hub.list_activities():
            print(f"  {activity.label} (id={activity.id})")

        await hub.start_activity("Watch TV")
        await hub.send_key("volume_up")
        result = await hub.set_channel("101")
        print(f"Channel via {result.method}")


asyncio.run(main())

Quick start (CLI)

export HARMONY_HUB_HOST=192.168.178.50

harmony info
harmony activities list
harmony activities start "Watch TV"
harmony key volume-up
harmony key mute
harmony key digit 5
harmony channel 101
harmony status
harmony doctor                          # end-to-end diagnostic
harmony discover                        # find Harmony Hubs

All read commands accept --json for machine-readable output. All logs go to stderr, so stdout stays scriptable.

CLI command reference

Every command resolves the hub host from (in order) --host, the HARMONY_HUB_HOST env var, or [hub].host in config.toml.

Top-level

Command	Purpose
harmony info [--json]	Hub identity: remote ID, redacted email, firmware, friendly name, discovery server.
harmony status [--json]	Current activity, last channel (library-tracked), connection state.
harmony power-off	Run the PowerOff activity.
harmony listen [--json]	Stream spontaneous hub events to stdout until Ctrl+C.
harmony send --device DEV --command CMD [--hold-ms N] [--json]	Send a raw IR command name to a specific device. Bypasses logical-key routing and aliases.
harmony doctor	End-to-end diagnostic: host reachability → port 8088 → provisioning → WebSocket → config.
harmony discover [--name N] [--id ID] [--timeout S] [--json]	Find hubs on the LAN via SSDP M-SEARCH and a parallel /24 port scan.
harmony channel <n> [--device DEV] [--json]	Switch channels. digits_then_enter (default) or native change_channel per config.
harmony activities list/current/start …	List, query, or switch activities (list, current, start).
harmony devices list/commands …	List all devices and their IR commands (list, commands).
harmony device power-on/off <device>	Power a single device on or off (power-on, power-off).
harmony key volume-up/down/mute/ok/back/digit …	Send a logical key with automatic routing (volume, channel, ok, back, digit).
harmony config pull/show/diff …	Fetch, display, or diff the hub config (pull, show, diff).
harmony sequence list/run …	List and fire hub-defined macro sequences (list, run).

Activities — harmony activities ...

Subcommand	Purpose
list [--json]	All activities defined on the hub.
current [--json]	The active activity (or PowerOff).
start <name-or-id>	Switch to an activity. Triggers device power-ons via the hub.

Devices — harmony devices ...

Subcommand	Purpose
list [--type KIND] [--json]	All devices: ID, label, kind, manufacturer, command count. --type filters by kind.
commands <device> [--group G] [--grouped] [--json]	List commands; --grouped groups by control group, --group <name> restricts to one.

Recognised --type values: television, avreceiver, speaker, stb, game, appletv, other.

Single-device shortcuts — harmony device ...

Subcommand	Purpose
power-on <device>	PowerOn (falls back to PowerToggle if configured).
power-off <device>	PowerOff.

Logical keys — harmony key ...

Each subcommand accepts --device to override routing and --host for the hub. Without --device, the key routes via [activity_routes.<label>] in config.toml; if no route is configured the lib picks the single device that owns the command, or fails with an ambiguity error.

Subcommand	Default route field	Notes
volume-up	volume_device	Honours [volume] repeat / hold_ms.
volume-down	volume_device	Honours [volume] repeat / hold_ms.
mute	volume_device	Single press; toggles AVR/TV mute.
channel-up	channel_device
channel-down	channel_device
ok	navigation_device	Alias chain: OK → Enter → Select → DirectionSelect.
back	navigation_device	Alias chain: Back → Return → Exit → PreviousMenu → DirectionBack.
digit <0-9>	number_device (falls back to channel_device)	Sends Number0…Number9 (or 0…9, depending on hub config).

harmony key digit 5 is the canonical form; harmony key 5 is not exposed — digits go through the digit subcommand.

Channel control — harmony channel

harmony channel <number> [--device DEV] [--json]

Switch channels. In digits_then_enter mode, presses each digit then Enter; in change_channel mode, fires the hub's native changeChannel command. The target device is taken from [activity_routes].channel_device for the active activity, or auto-resolved. Pass --device to override.

Hub-config helpers — harmony config ...

• pull [--out PATH] — fetch the raw hub config and write it as JSON (stdout when --out omitted).
• show [--json] — parsed summary: version, locale, devices (kind, capabilities, control groups), activities (roles), sequences.
• diff [--json] — compare the on-disk cached config to a fresh pull; surfaces added/removed devices, activities, commands, and configVersion bumps.

Sequences — harmony sequence ...

Hub-defined macros (multi-step IR runs configured in the Harmony app):

Subcommand	Purpose
list [--json]	List sequences with ID, label, and step count.
run <sequence-id>	Fire every step in order. Reports per-step success / failure rows.

Shell completions (zsh)

Auto-install (modifies ~/.zshrc):

harmony --install-completion zsh
exec zsh    # or open a new shell

Manual install (no edits to ~/.zshrc; uses $fpath):

mkdir -p ~/.zfunc
harmony --show-completion zsh > ~/.zfunc/_harmony
# add to ~/.zshrc once:
#   fpath=(~/.zfunc $fpath)
#   autoload -U compinit && compinit

Completion drives off the live binary, so it stays in sync as new subcommands are added.

Exit codes

Code	Meaning
0	success
2	usage / validation error
10	hub unavailable on the network
11	protocol error (timeout, malformed payload)
12	command or alias not found
13	routing ambiguous — pass an explicit --device

Configuration

The library reads ~/.config/harmony-local/config.toml (or %APPDATA% on Windows). Every value can be overridden by an environment variable or a CLI argument (precedence: CLI > env > file > default).

[hub]
host = "192.168.178.50"

[connection]
mode = "persistent"            # persistent | ondemand
protocol = "websocket"         # websocket | xmpp
keepalive_interval_s = 50
request_timeout_s = 10

[channel]
mode = "digits_then_enter"     # digits_then_enter | change_channel
inter_digit_delay_ms = 150
send_enter = true

[volume]
# Fired per `harmony key volume-up` / `volume-down` (mute is always single).
repeat = 1                     # IR presses per logical key (raise for AVRs with fine steps, e.g. 4 → 2 dB on Yamaha)
hold_ms = 0                    # extra IR hold per press (some AVRs need ≥100 ms to register repeat-frames)
inter_press_delay_ms = 80      # gap between repeats when repeat > 1

[activity_routes."Watch TV"]
volume_device = "Denon AVR"
channel_device = "Vodafone Receiver"
navigation_device = "Vodafone Receiver"
number_device = "Vodafone Receiver"

Recognised environment variables: HARMONY_HUB_HOST, HARMONY_PROTOCOL, HARMONY_CONNECTION_MODE.

MCP server

harmony-mcp runs the FastMCP server over stdio. Wire it into Claude Desktop:

{
  "mcpServers": {
    "harmony": {
      "command": "harmony-mcp",
      "args": [],
      "env": { "HARMONY_HUB_HOST": "192.168.178.50" }
    }
  }
}

Tools exposed:

• harmony_get_status — current activity, last channel, connection state.
• harmony_list_activities, harmony_start_activity, harmony_power_off.
• harmony_list_devices, harmony_list_device_commands.
• harmony_device_power_on, harmony_device_power_off.
• harmony_send_key — typed LogicalKey (volume/channel up-down, digits, ok, enter, back, off). Routing falls back to TOML activity_routes, then auto-resolution.
• harmony_send_command — raw IR command on a device (for vendor-specific buttons not covered by send_key).
• harmony_set_channel — digits_then_enter or native change_channel.
• harmony_refresh_config — re-fetch and replace the cached config.

Resources exposed: harmony://config, harmony://activities, harmony://devices, harmony://status.

The server never logs to stdout (that would corrupt the MCP framing) and does not return raw account IDs or unredacted email addresses.

Natural-language skill

A drop-in skill for Claude Code / Claude Desktop lives at skill/harmonyhub/SKILL.md. It teaches the model to translate voice-style requests ("schalte Pro7 ein", "lauter", "alles aus") into the matching MCP tool calls or CLI invocations.

Highlights:

• Hard rule: channel requests are only valid when the active activity is Fernsehen. The skill checks harmony_get_status first and starts the activity if needed before calling harmony_set_channel.
• Channel-name → number map (ARD=1, ZDF=2, RTL=3, Sat1=4, Pro7=5, …).
• Activity aliases for this hub: Fernsehen, Apple TV sehen, Musik hören, TV, PowerOff.
• Volume / mute / OK / Back / channel ±/digit routing tables.
• Replies in the user's language in one short sentence — no tool names, no JSON.

See docs/skill.md for installation notes.

What the library will not tell you

The hub is a one-way IR transmitter for most operations, so the library is honest about what it cannot know:

Question	Verdict
Which activity is active?	Reliable — read directly from the hub.
What is the current channel?	Unknown to the hub. Tracked only when set via this library, with last_channel_source flagged.
Is a specific device powered on?	Inferred from the active activity; unverified.
Was the user pressing buttons on the original remote?	Invisible to the hub.

If anything outside Harmony changed a device's state, the library will not pretend otherwise. Run harmony status to inspect what is actually known.

Documentation

File	Summary
docs/protocol.md	Raw WebSocket/HTTP payloads the library uses; reverse-engineered hub wire format.
docs/routing.md	How logical keys resolve to a target device — precedence rules and config examples.
docs/skill.md	Installation guide for the Claude Code natural-language agent skill.
docs/troubleshooting.md	Common errors (HTTP 401, timeout, provisioning failures) and fixes.

Tests

pytest                                       # unit + simulator tests, no real hub needed
HARMONY_HUB_HOST=... pytest -m integration   # opt-in real-hub smoke test

Repository layout

See spec/harmony_hub_implementierungsplan(1).md for the full design plan. Runtime code lives in harmonyhub/:

harmonyhub/
├── client.py          # HarmonyHubClient — public API
├── models.py          # Frozen dataclasses (Device.command_actions maps function.name → IR command)
├── exceptions.py      # Error hierarchy
├── aliases.py         # Logical-key → IR-command fallbacks
├── status.py          # last_channel persistence
├── cache.py           # XDG paths, JSON cache helpers
├── config.py          # TOML loader + env overlay (Connection / Channel / Volume / ActivityRoute)
├── discovery.py       # mDNS stub (post-MVP)
├── cli.py             # Typer CLI (zsh completion via `--install-completion zsh`)
├── mcp_server.py      # FastMCP server
├── simulator.py       # Fake hub (WebSocket only — HTTP mocked in tests)
└── protocol/
    ├── http.py        # Provisioning POST (exports HUB_ORIGIN constant)
    ├── websocket.py   # WebSocket transport — request/response + fire-and-forget notify()
    └── xmpp.py        # Stub (post-MVP)