myIO MCP Server

myIO MCP Server

Talk to your home. myIO MCP connects AI assistants such as Claude to a myIO smart home controller, so you can ask the house in plain words how warm the children's room is, what happened today, or to lower the blinds.

myIO is a central home controller developed in Hungary by myIO Smart Home Zrt. It sits on a DIN rail in the distribution cabinet and runs heating and cooling, lighting, blinds, gates and energy in one system, on its own, without the internet. This is a free, open-source Model Context Protocol (MCP) server for it: it runs on your own computer and reaches the controller over your home network, through its HTTP API.

Example

A real conversation in Claude Desktop, translated from Hungarian:

You: How warm is it in the house right now, room by room?

Claude (used myIO-MCP): Right now (20:02), according to the controller:

Room	Temperature
Bedroom	23.6 °C
Bedroom bathroom	23.3 °C
Study	26.0 °C

It is 5.3 °C outside, and the heating flow water is at 32.3 °C. The study is noticeably warmer than the others. Only the upstairs myIO controller is reachable, so I have no data on the ground-floor rooms.

You: Switch on the study lamp and lower the blinds upstairs.

Claude (used myIO-MCP): The study lamp is on, and all 9 upstairs blinds are going down: bedroom (terrace door, east, south), study, walk-in closet, guest bedroom, bathroom, staircase and guest bathroom.

One thing worth knowing: your own "Upstairs blinds DOWN" group does not include the study blind, and there is also a "Study blind down lock" switch. It is off right now, so I lowered the study blind too. If it was left out of the group on purpose, tell me and I'll raise it again.

Quick start (Claude Desktop)

1. Download myio-mcp.mcpb.
2. Open it with a double click (or in Claude Desktop: Settings → Extensions).
3. Enter the controller's address (e.g. http://192.168.1.178), a user name and the password. Then ask.

Create a separate myIO user for the assistant, and choose how far it may go: switch only (state), change settings too (config, the default) or everything (admin). Claude Code and other MCP clients: see Configuration.

Works with every myIO controller: V3 (Arduino Due, firmware 3.12), V4 GIGA and V4 Opta (firmware 4.x). Features that only exist on V4 answer with a clear error on a V3. More: Talk to your home · Downloads · API reference (Hungarian)

Privacy: the MCP server runs locally, but the AI assistant runs on its provider's servers. Your questions, and what it reads to answer them (e.g. temperatures, output names), reach the provider.

Status (1.6.1, 2026-11-13)

1.6.1: myio_system restarts and updates a Due (3.12+) over the web too - the MYIO_NEW.BIN package is checked against the controller's chip ID before upload, and the answer says whether it was installed, rejected or cannot be installed (no device key).

Rounds 0-5 of the plan: the February 2026 server fixed, put on tests, extended with the house entities, the configuration layer, automation (Flow rules, myIO Script programs), diagnostics / logs / files, every integration and RS485 expander - and in round 5 the MCP layer: resources, prompts, toolsets, consistent annotations and an optional Streamable HTTP transport.

• native node:http client (no more curl), one request at a time per controller, Connection: close
• correct value scales: temperature ×100, humidity ×10, SDM voltage/current ×10, SDM power in W, PCA/FET level raw 0..255
• every control tool reads the state back and reports what the controller actually did (a command the account has no permission for is silently dropped by the firmware)
• several controllers in one server (MYIO_SERVERS), every tool takes a server name
• version gate: V3 (Due 3.12) and V4 (GIGA/Opta 4.x) both supported, 4.x-only features answer with a clear error on a Due
• entities modelled like the myIO app / Homey / Home Assistant integration: thermostat zones, shutters (protection pairs), RGB groups, wall inputs, universal sensors
• configuration layer: globals, names, output/input configuration, protection pairs / joiners / groups, scenes, timers, users and permissions - toggle-type settings are read first and only sent when they must change
• automation: Flow rules described in plain words with element names, validated against the firmware's card rules BEFORE upload (the firmware silently disables a rule with a bad card), saved + reloaded + read back; scripts written, compiled on the controller, compile errors returned with the offending source line; the complete script language reference is a tool (myio_reference)
• diagnostics: health snapshot (resets, loop stalls, RAM, sockets, WiFi, NTP on a Due), Prometheus metrics, daily logs with level / text / time filters, file manager on internal flash and SD card (system files need MYIO_WRITE=admin)
• integrations: Shelly, myIO Link, MQTT, myIO Cloud, SG-Ready, alarm panel (SIA), MIA, LED strips, network, restart / web OTA; Opta expanders: failsafe / AUX / 1-Wire, KNX (table, names, ETS interface, device programming), DALI, DMX, Modbus RTU. Toggle-type settings are always given as desired values; passwords, keys and tokens are never returned; a value containing & is refused (the firmware cannot receive it)
• write level (MYIO_WRITE = state | config | admin) limits what the AI may change
• MCP layer: resources (myio://<controller>/state ...), four prompts in Hungarian and English that read the controller first, toolsets (MYIO_TOOLSETS) to save context, annotations that follow one rule set, Streamable HTTP for other LAN clients (bearer token)
• zod input schemas, mock controller + end-to-end tests (npm test, 72 tests), restoring live tests for a bench controller

Tools (102)

Tool	Toolset	What it does
myio_servers	core	the configured controllers with a live check (version, name, permission level)
myio_info	core	serial, firmware version, board, element counts (RQ/SQ/PCAQ/SENQ), permission level, feature flags, expanders, storage health
myio_find	core	name search (accent- and case-insensitive) across outputs, groups, sensors, inputs, universal sensors
myio_list_devices	core	outputs with id, name, live state/level, roles (thermostat, shutter-up/down, rgb:, group: ...), timers, members
myio_read_sensors	core	temperatures (°C), humidity (%), pulse meter, SDM630 power/voltage/current, 4.x universal sensors
myio_get_status	core	any raw JSON endpoint (sens_out.json, sens_IO.json, info.json, 4.x: usensor.json, sysdiag.json, ...)
myio_output	core	switch or dim ANY output by id: action on / off / toggle / level (level 0..255 or percent)
myio_relay_on / _off / _toggle	legacy	relay 1..RQ
myio_pca_on / _off / _toggle / myio_pca_set	legacy	PCA dimmer channel 2001..2000+PCAQ; set takes level (0..255) or percent (0..100)
myio_pwm_on / _off / _toggle / myio_pwm_set	legacy	FET/PWM output 101..116 (legacy hardware only)
myio_group_on / _off / _toggle	legacy	group 501.. (editor level needed on the controller)
myio_inputs	house	wall buttons / switches: state, name, enabled, NC (4.3.12+ / Due 3.12.7+)
myio_press_button	house	simulate a button: hit (short), press (long), release - runs the input's bound actions
myio_thermostats / myio_set_thermostat	house	sensor-controlled zones: target + band (hysteresis), heat/cool, current temperature; set target, band, raw thresholds, bind sensor
myio_shutters / myio_shutter	house	UP/DOWN pairs (protection pairs): opening / closing / stopped; open, close, stop
myio_rgb / myio_set_rgb	house	RGB groups ("RGB..." group with R/G/B channels): on/off, colour, brightness
myio_usensors / myio_set_usens	house	4.x universal sensors (KNX, Modbus, MQTT, Shelly, Script, external): read; push a value from outside
myio_send_command	core	raw key=value&key=value command string (everything in the API reference); the reply lists the outputs that changed
myio_globals / myio_set_globals	config	name, clock, time zone, location, sunrise/sunset, button timing, cooldown, sensor polling, pulse meter unit; NTP sync
myio_rename	config	name of a relay / pca / fet / group / input / thermo / humidity / usens / shelly / scene
myio_output_config / myio_set_output_config	config	auto-off timer, delay, inverted, alarm, justOn, PCA min/max, fade speed, PWM / mixer mode
myio_input_config / myio_set_input_config	config	what a wall button does: enabled, NC, hit-block, hit / press / release targets
myio_structures / myio_set_protection / myio_set_joiner / myio_set_group	config	protection pairs (shutters), joiner pairs, group members and pullUp
myio_scenes / myio_scene	config	configuration slots: list, load, save, new, delete, set_boot, rename
myio_timers / myio_set_timer / myio_delete_timer	config	timer.csv: time or sunrise/sunset ± offset, date, weekdays, event and target
myio_users / myio_user	config	accounts: list, new, delete, rename, set_password, set_rights (admin level)
myio_permissions / myio_set_permissions	config	per-element read/write and hit/press permissions of a user (map readable on 4.x)
myio_config_vars	config	any raw setting variable of the Setup page (energy manager, SDM, dew point ...)
myio_flows	automation	Flow rules (4.4+): WHEN / AND / THEN in plain words with names, live state (enabled, running, last fired), variables, webhooks; raw = flows.jsn
myio_flow_save	automation	add / replace / delete a rule, a variable or a webhook target, or replace the whole flows.jsn - validated first, then uploaded + reloaded + read back (dry_run)
myio_flow	automation	runtime: enable / disable a rule, fire its actions now, set a global variable
myio_flow_trace / myio_webhook_test	automation	what the engine did (incremental with since); fire a webhook slot and report the HTTP result
myio_scripts / myio_script_get	automation	myIO Script programs (4.10+): state, errors with line:col, timing, locals, arrays, global variables, trace; source of a slot
myio_script_save / myio_script	automation	write + compile a program (compile error with the source line); reload, run once, enable / disable (RAM or persistent), delete
myio_reference	automation	the bundled firmware documentation: complete script language, Flow card format, any API section
myio_sysdiag / myio_metrics	diag	health: uptime, last reset cause, loop stalls, RAM, M4 core, LAN/WiFi, sockets, storage, login brake; Prometheus text (4.4.1+)
myio_logs / myio_log	diag	daily CSV logs (event, consumption, SDM, temperature, humidity, usens): list; read one day with level / text / time filters and tail
myio_files / myio_file_read / myio_file_write / myio_file_op	diag	storage (internal flash q, SD card s; a Due has only the SD): list, read (text / binary), write (text / base64, make_dirs), delete / mkdir / rename / copy
myio_fm_sync	diag	internal flash -> SD configuration mirror: status, run, adopt a foreign card (4.4.3+, admin)
myio_shelly / myio_shelly_set	integrations	Shelly devices (4.1+): online, state, which myIO output / button / usens each channel is bound to; add, scan, bind, rename, auth, push
myio_link / myio_link_set	integrations	myIO Link (4.2+): other controllers polled, output and sensor links; add, scan, link, unlink
myio_mqtt / myio_mqtt_set	integrations	MQTT client (4.3+, Due 3.12.31+): broker, state, topics, HA discovery, publish masks, subscribe, external sensor bindings; save + reconnect
myio_cloud / myio_cloud_set	integrations	myIO Cloud (4.4+): state, pairing window, paired phone keys; enable, pair, revoke, delete (admin)
myio_sgready / myio_sgready_set	integrations	SG-Ready heat pump (4.4.2+, Due 3.12.9+): mode 1..4, K1/K2 outputs, utility-lock limit
myio_alarm / myio_alarm_set	integrations	SIA DC-09 alarm panel receiver (4.5.8+): partitions, troubles, counters; listeners, account, partition -> usens, simulated events
myio_mia / myio_mia_set	integrations	MIA self-learning heating (4.11+): learned zone model, window detection, preheating; features, thresholds, exclusions, reset
myio_ledstrip / myio_ledstrip_set	integrations	WS2812 strips (4.3.4+): strips, programs, effects; run/stop by event id, edit programs live
myio_network / myio_network_set	integrations	host name, LAN, WiFi STA/AP, live addresses, services per interface; change + save or apply (admin, dangerous)
myio_system	integrations	restart, web OTA upload / install (GIGA/Opta: MYIO_UPD.BIN + roll back; Due 3.12+: MYIO_NEW.BIN to the SD card, checked for the controller's chip ID before upload), admin - waits for the controller and reports the running version and the outcome
myio_expanders / myio_expander_set	expanders	Opta RS485 panels (4.5+): type, online, firmware, failsafe/standalone, AUX mode, Ext16 1-Wire
myio_knx / myio_knx_set / myio_knx_device	expanders	Ext-KNX: group-address table with names, ETS tunnelling interface, devices; edit rows + KnxSave, scan / program addresses (admin)
myio_dali / myio_dali_set	expanders	Ext-DALI (4.8.6+): endpoints, bindings, desired vs driver parameters, groups; bind, settings, groups, scan, commission (admin)
myio_dmx / myio_dmx_set	expanders	Ext-DMX (4.9+): fixtures and channel bindings; add, bind, test, blackout
myio_modbus / myio_modbus_set	expanders	Ext-RS485 Modbus RTU (4.16+): blocks, decoded fields with live values, writer slots, bus; edit tables, presets, raw request, address scan

Element ids are shared by all tools and channels: relays 1..RQ, FET 101..116, groups 501.., PCA 2001..2000+PCAQ (see API_REFERENCE.md chapter 3).

Annotations follow one rule set: read tools are readOnlyHint; a desired-value setter (on / off / level / target / name / a setting) is idempotentHint - calling it twice changes nothing more (an identical protection pair, joiner or timer is reused, not duplicated); toggles, fire / run, button presses and add / new actions are not; tools that can overwrite or delete stored configuration are destructiveHint (switching an output is a reversible state change, not destructive); a tool with several actions is annotated for its most dangerous one. myio_webhook_test is openWorldHint (it calls an outside URL).

Toolsets

The 102 tool descriptions cost context. MYIO_TOOLSETS loads only some groups (the same field is in the Claude Desktop settings):

Toolset	Tools
core (always)	myio_servers, myio_info, myio_find, myio_list_devices, myio_read_sensors, myio_get_status, myio_output, myio_send_command (8)
legacy	the per-type switches from 2026-02: myio_relay_* / myio_pca_* / myio_pwm_* / myio_group_* (14) - myio_output covers them
house	inputs, button simulation, thermostats, shutters, RGB, universal sensors (10)
config	settings, names, output / input configuration, structures, scenes, timers, users, permissions (21)
automation	Flow rules, scripts, the language / API reference (10)
diag	sysdiag, metrics, logs, files, SD mirror (9)
integrations	Shelly, Link, MQTT, Cloud, SG-Ready, alarm, MIA, LED strips, network, restart / OTA (19)
expanders	Opta RS485 expanders: Ext16, KNX, DALI, DMX, Modbus (11)

Examples: MYIO_TOOLSETS=house,automation (core + 20), MYIO_TOOLSETS=all,-legacy,-expanders (77). Empty or all = everything (default). Unknown names are reported on stderr; core cannot be switched off. The server instructions tell the model which groups are not loaded, and the prompts only mention tools that are. Resources and prompts do not depend on the toolsets.

Resources

Attachable context - the client reads them without a tool call. <controller> is the URI-safe form of the controller name (Földszint -> foldszint, Ground floor -> ground-floor; printed on stderr at start).

URI	Content
myio://<controller>/info	info.json + the feature map derived from the firmware version (JSON)
myio://<controller>/state	decoded live state in real units: outputs (level, roles, timers, thermostat thresholds), sensors, inputs, universal sensors (JSON)
myio://<controller>/flows.jsn	the Flow rule file (4.4+)
myio://{controller}/prog/{n}.txt	template: source of script slot n (4.10+)
myio://{controller}/log/{date}	template: one day of the event log, today / yesterday / YYYY-MM-DD / YYMMDD (last 256 KB)
myio://docs/index	contents of the bundled API reference with the chapter URIs
myio://docs/script / myio://docs/flow	the myIO Script language (10/G) / the Flow card format (10/D)
myio://docs/chapter/<id>	one chapter: 1 .. 13, 10-a .. 10-h (Hungarian)
myio://docs/search/{query}	template: every section whose heading contains the query (accent-insensitive)

The templates offer completion (controller names, slot numbers, the last seven days).

Prompts

Each prompt reads the controller(s) when it is requested and embeds the data, so the conversation starts with full context (every data block fails on its own: "not available: ..."). Argument language: hu (default) or en; server limits it to one controller.

Prompt	Arguments	What it collects
heating_overview	server, language	thermostat zones (target, band, current, heating), temperatures and humidity, MIA learned model and today's MIA events, SG-Ready - for every controller
why_not_switching	element (name or id), server, language	the output's state and roles, account level, output configuration, thermostat control, protection / joiner / group, timers and scene loads, bound wall buttons, Flow rules and scripts that use it, myIO Link, MQTT control, SG-Ready contacts, today's switching commands for it in the event log. An ambiguous name returns the candidates.
daily_diagnostics	server, date, language	info, sysdiag (resets, RAM, sockets, link / WiFi, NTP), clock vs this computer + time zone / DST, the event log's error and notable lines grouped, RS485 expanders, Flow and script errors - for every controller
new_flow_rule	rule (plain words), server, language	the existing rules, the named outputs and sensors with ids, the 10/D card reference; the model is told to clarify, draft, dry-run (myio_flow_save dry_run=true), explain, and save only after approval

Streamable HTTP (optional)

stdio stays the default. With MYIO_HTTP_PORT the server also answers MCP over Streamable HTTP at /mcp, for other MCP clients on the LAN:

MYIO_HTTP_PORT=8765 MYIO_HTTP_HOST=0.0.0.0 MYIO_HTTP_TOKEN=$(openssl rand -base64 24) \
MYIO_BASE_URL=http://192.168.1.178 MYIO_USERNAME=admin MYIO_PASSWORD=... node dist/index.js
# client: URL http://<this-machine>:8765/mcp, header  Authorization: Bearer <token>

• binds to 127.0.0.1 by default; any other address needs MYIO_HTTP_TOKEN (min. 16 characters) or the server refuses to start. On loopback without a token a random one is generated and printed on stderr.
• every request needs Authorization: Bearer <token> (compared in constant time); sessions are kept in memory (max 16, idle 30 min).
• all sessions share the controller clients, so the per-controller request queue (and MYIO_MIN_GAP_MS) still protects the firmware.
• started from a terminal it serves only HTTP; under an MCP client (stdin is a pipe) stdio runs too. MYIO_STDIO=0|1 forces it.
• plain HTTP: use it inside the home network or behind a TLS reverse proxy / VPN, not on the open internet. On macOS the application firewall may ask to allow incoming connections for node.

Configuration

Environment variables (the Claude Desktop extension asks for them as user config):

Variable	Meaning
MYIO_BASE_URL	controller URL, e.g. http://192.168.1.178 (port 80 by default)
MYIO_USERNAME / MYIO_PASSWORD	HTTP Basic auth; the account's permission level limits what the tools can do
MYIO_NAME	label used in replies (default: the host)
MYIO_SERVERS	several controllers: JSON array [{"name":"Ground floor","url":"http://192.168.1.178","username":"admin","password":"..."}, ...] - overrides the three above; tools take server: "<name>"
MYIO_WRITE	write level: state (outputs, thermostat targets, usens, run flows / scripts, SG mode), config (default; also names, timers, scenes, structures, input/output configuration, thermostat sensor binding, Flow / script files, integration settings), admin (also users, permissions, system files, network, Cloud keys, restart / OTA)
MYIO_TOOLSETS	tool groups to load (see Toolsets), default all
MYIO_HTTP_PORT / MYIO_HTTP_HOST / MYIO_HTTP_TOKEN / MYIO_STDIO	optional Streamable HTTP transport (see above)
MYIO_TIMEOUT_MS	HTTP timeout, default 10000
MYIO_MIN_GAP_MS	minimum pause between two requests to one controller, default 150 (a Due refuses request bursts)
MYIO_INSECURE_PARSER	0 = strict Node HTTP parser (default lenient: the firmware writes its headers by hand)

Claude Desktop

Install myio-mcp.mcpb (Settings → Extensions) and fill in the URL, user and password. To rebuild the bundle:

npm install
npm run pack          # = sync-docs + tsc + mcpb pack . myio-mcp.mcpb

Claude Code / other MCP clients (stdio)

The server is on npm as myio-mcp (Node.js 18 or later), so npx runs it without a checkout:

{
  "mcpServers": {
    "myio": {
      "command": "npx",
      "args": ["-y", "myio-mcp"],
      "env": { "MYIO_BASE_URL": "http://192.168.1.178", "MYIO_USERNAME": "admin", "MYIO_PASSWORD": "..." }
    }
  }
}

Claude Code: claude mcp add myio -e MYIO_BASE_URL=http://192.168.1.178 -e MYIO_USERNAME=admin -e MYIO_PASSWORD=... -- npx -y myio-mcp. From a checkout, use "command": "node" with "args": ["/absolute/path/to/myio-mcp/dist/index.js"] instead.

It is also listed in the official MCP Registry as io.github.SmarthomeNinja/myio-mcp (server.json).

Development

npm install
npm run build         # TypeScript -> dist/
npm test              # build + mock controller + end-to-end tests over stdio (node --test)
MYIO_BASE_URL=http://192.168.1.56 MYIO_USERNAME=admin MYIO_PASSWORD=... npm run smoke   # read-only check on a real controller
node test/mock_myio.mjs --serve 8111    # standalone mock controller (MOCK_VERSION=3.12.30 for a Due-like one)
npm run sync-docs     # copy ../SD_Files/js/lang/HU/API_REFERENCE.md (the canonical reference) into the package; --check only compares
LIVE_SERVERS='[{"name":"Opta","url":"http://192.168.1.60","username":"admin","password":"..."}]' node test/live_mcp5.mjs   # resources + prompts + HTTP, read-only

Layout: src/api.ts (HTTP client + command dispatch), src/model.ts (JSON → devices/sensors, scales, version gate), src/model_auto.ts (Flow validation / description, script state, traces), src/model_diag.ts (sysdiag, logs, files), src/servers.ts (several controllers, URI slugs), src/toolsets.ts (MYIO_TOOLSETS), src/resources.ts, src/prompts.ts, src/docs.ts (the bundled reference), src/http.ts (Streamable HTTP), src/tools/common.ts (read-back, desired-toggle and command helpers), src/tools/basic.ts + house.ts + config.ts + auto.ts + diag.ts + integr.ts + bus.ts (tool families on McpServer), src/index.ts (config + transports), test/mock_myio.mjs (controller mock built from the real d_sens_out.json sample, with an in-memory file system, Flow and Script engines), test/mcp.test.mjs, test/house.test.mjs, test/config.test.mjs, test/auto.test.mjs, test/integr.test.mjs, test/mcp5.test.mjs (resources, prompts, toolsets, annotations, HTTP); test/live_write.mjs, test/live_config.mjs, test/live_auto.mjs and test/live_integr.mjs are restoring live tests for a BENCH controller only; test/live_mcp5.mjs only reads. node test/call.mjs <tool> '<json>' ... calls tools by hand.

Rules the server follows (from the API reference, chapter 12)

1. One request at a time, Connection: close, no polling faster than 1 s - the controller has 3 listen sockets.
2. Commands go as POST /info.json body (the GET /command: path does not URL-decode), max 1024 bytes.
3. The command reply is an HTML/JSON acknowledgement, not the new state: read sens_out.json back.
4. JSON keys may be missing (permission filtering): never rely on a fixed key set.
5. Toggle-type config commands (relaysInvert=<id> ...) invert a flag - read first, send only on change.
6. Fixed point: temperature ×100, humidity/usens/SDM U,I ×10, thresholds ×10, PCA/FET level raw 0..255.

License

MIT, see LICENSE.