Sparkplug B

io.github.nagarjunrPublished by GitHub account nagarjunrv0.1.0Updated Oct 24, 2026

MCP server for Sparkplug B: node/device discovery, metrics, commands, host state over MQTT.

VerifiedSTDIODesktop onlyCloud & Infrastructure Developer Tools Data & Analytics

Server details

Identifier: io.github.nagarjunr/sparkplug-b
Transport: STDIO
Runtime: Desktop only
Trust: Verified
Published: Sep 16, 2026

Security note

MCP servers receive tool arguments from a conversation and may perform external actions. Review what a server can do before you enable it, and give it only the access it needs.

The registry verified the GitHub account nagarjunr for this listing. That does not show the account is the product's maker.

SourceWeft's checks cover whether the listing is complete and the endpoint answered; they do not review the server's code or what its tools do.

Add a badge to your README

Show readers this MCP server is listed on SourceWeft. The badge links to this page.

[![Listed on SourceWeft](https://sourceweft.com/badge/mcp/io.github.nagarjunr%2Fsparkplug-b.svg)](https://sourceweft.com/mcp/io.github.nagarjunr%2Fsparkplug-b?utm_source=readme&utm_medium=badge)

Overview

AI-generated overview

Sparkplug B MCP server that acts as a Primary Host Application over MQTT, letting an assistant discover edge nodes and devices, read metrics, send commands…

What you can do: Check broker connection status and publish this host's own retained STATE message
List discovered edge nodes and devices, and read their latest metric values
Send node and device commands to write metrics, and request a node rebirth
Start, drain, list and stop watch sessions that buffer decoded Sparkplug traffic matching a filter
When to use it: Useful when an assistant needs to inspect or operate an industrial/SCADA Sparkplug B deployment on an MQTT broker: discovering nodes and devices, reading live metrics, issuing commands, or monitoring births, deaths and data messages.
Requirements: Runs locally as a Python package via uvx (stdio). Needs a reachable MQTT broker and the required environment variables SPARKPLUG_MQTT_HOST and SPARKPLUG_HOST_ID; optional settings cover port, username/password, TLS and CA/client certificates, client ID, keepalive, connect timeout and a group filter. Desktop only.

Before you install

Commands write metric values to real nodes and devices, and set_host_online publishes a retained STATE message, so actions affect live equipment. Broker credentials are supplied through SPARKPLUG_MQTT_USERNAME and SPARKPLUG_MQTT_PASSWORD, and mutual TLS may need client certificate and key paths. By default it subscribes to every group in the spBv1.0 namespace, so it sees all traffic on the broker.

Installation

In SourceWeft

Open Sparkplug B in the dashboard and add it to a workspace.
Enable the server for the chats that should use its tools.

Desktop only via STDIO. STDIO servers start a local process, so they need the SourceWeft desktop host.

Other MCP clients

Follow the launch instructions in the repository.

README

Sparkplug B MCP Server

A Model Context Protocol (MCP) server for Sparkplug B — the Eclipse-standard MQTT topic/payload convention for industrial/SCADA data (birth/death certificates, sequenced metrics, protobuf payloads). Works against any MQTT broker that carries Sparkplug B traffic; only the open Sparkplug B specification is used, no vendor-specific extensions.

This server acts as a Sparkplug B Primary Host Application: it subscribes to the entire spBv1.0 namespace, discovers Edge Nodes and Devices from their NBIRTH/DBIRTH messages, tracks their live metrics, and can send them commands (NCMD/DCMD) — the same role a SCADA/historian host application plays in a real deployment.

Built with FastMCP and pysparkplug (itself built on paho-mqtt).

Tools

Tool	Description
`get_connection_status()`	Report the broker connection and this host application's identity.
`set_host_online(online)`	Publish this connector's own retained Sparkplug `STATE` message.
`list_edge_nodes(group_id?)`	List Edge Nodes discovered via `NBIRTH`/`NDEATH`.
`list_devices(group_id?, edge_node_id?)`	List Devices discovered via `DBIRTH`/`DDEATH`.
`get_node_metrics(group_id, edge_node_id)`	Latest known metric values for an Edge Node.
`get_device_metrics(group_id, edge_node_id, device_id)`	Latest known metric values for a Device.
`send_node_command(group_id, edge_node_id, metrics)`	Send an `NCMD` — write one or more of a node's metrics.
`send_device_command(group_id, edge_node_id, device_id, metrics)`	Send a `DCMD` — write one or more of a device's metrics.
`request_node_rebirth(group_id, edge_node_id)`	Standard `Node Control/Rebirth` command — asks a node to republish its full `NBIRTH`.
`start_watch(group_id?, edge_node_id?, device_id?, message_types?)`	Start buffering decoded Sparkplug traffic matching an optional filter. Returns a `session_id`.
`get_events(session_id, max_events, timeout_seconds)`	Drain buffered events from a watch session; can wait briefly for one to arrive.
`stop_watch(session_id)`	Stop a watch session and discard its buffered events.
`list_watches()`	List all active watch sessions.

Why watching is session-based

Like the MQTT wire protocol underneath it, Sparkplug B is a continuous stream, not a request/response API — a single MCP tool call can't "wait forever" for the next birth or data message. start_watch registers an optional filter (group/node/device/message-type) and buffers matching decoded messages in the background (this connector is always subscribed to the whole spBv1.0 namespace, so no extra broker subscription is needed per watch); get_events drains that buffer, optionally waiting a bounded amount of time for new data. Call stop_watch when done.

Supported metric datatypes

INT8/INT16/INT32/INT64, UINT8/UINT16/UINT32/UINT64, FLOAT, DOUBLE, BOOLEAN, STRING, TEXT, UUID, DATETIME, BYTES, FILE, and their *_ARRAY variants. DATASET, TEMPLATE, PROPERTYSET, and PROPERTYSETLIST are part of the Sparkplug B spec but unsupported by the underlying pysparkplug codec, so they're rejected with a clear error rather than silently mishandled.

For send_node_command/send_device_command, value shape depends on datatype: plain int/float/bool/str for scalars, an ISO 8601 string for DATETIME, a base64 string for BYTES/FILE, and a JSON list for *_ARRAY types.

Configuration

Env var	Required	Description
`SPARKPLUG_MQTT_HOST`	Yes	Broker hostname or IP.
`SPARKPLUG_HOST_ID`	Yes	This connector's Sparkplug Host Application ID (used in the `spBv1.0/STATE/{id}` topic).
`SPARKPLUG_MQTT_PORT`	No	Default `1883`.
`SPARKPLUG_MQTT_USERNAME` / `SPARKPLUG_MQTT_PASSWORD`	No	Broker credentials.
`SPARKPLUG_MQTT_CLIENT_ID`	No	Defaults to a broker-assigned ID.
`SPARKPLUG_MQTT_KEEPALIVE`	No	Seconds, default `60`.
`SPARKPLUG_MQTT_CONNECT_TIMEOUT`	No	Seconds to wait for the initial connect, default `10`.
`SPARKPLUG_MQTT_USE_TLS`	No	`true`/`false`, default `false`.
`SPARKPLUG_MQTT_TLS_CA_CERTS`	No	Path to a CA bundle. Omit to use the system trust store.
`SPARKPLUG_MQTT_TLS_CLIENT_CERT` / `SPARKPLUG_MQTT_TLS_CLIENT_KEY`	No	For mutual TLS.
`SPARKPLUG_GROUP_ID`	No	Restrict discovery/watching to a single Sparkplug Group ID. Omit to subscribe to every group (`spBv1.0/#`).

Running locally

bash

uv syncexport SPARKPLUG_MQTT_HOST=localhostexport SPARKPLUG_MQTT_PORT=1883export SPARKPLUG_HOST_ID=my-mcp-hostuv run sparkplugbmcpserver.py

uv syncexport SPARKPLUG_MQTT_HOST=localhostexport SPARKPLUG_MQTT_PORT=1883export SPARKPLUG_HOST_ID=my-mcp-hostuv run sparkplugbmcpserver.py

See mcp.json for ready-to-use client configs (stdio and Docker).

Testing against a real broker

This repo's design principles call for testing against a real instance rather than mocks. docker-compose.yml spins up Eclipse Mosquitto (2.x) with an anonymous listener for local testing. Test fixtures use pysparkplug's own EdgeNode/Device classes to act as real simulated PLCs/devices — publishing genuine NBIRTH/DBIRTH/NDATA/DDATA/NDEATH messages and receiving genuine NCMD/DCMD commands over the wire — so coverage is protocol-level, not hand-rolled mocks. Only the "physical" node/device is simulated, since no free real PLC/edge-node hardware exists to test against; the Sparkplug B protocol handling on both sides is real.

bash

docker compose up -d       # start Mosquitto on localhost:1883 (anonymous, local testing only)uv run pytest -v           # tests/conftest.py also starts/stops the stack automaticallydocker compose down        # stop it manually if you started it yourself

docker compose up -d       # start Mosquitto on localhost:1883 (anonymous, local testing only)uv run pytest -v           # tests/conftest.py also starts/stops the stack automaticallydocker compose down        # stop it manually if you started it yourself

License notes

docker-compose.yml and the files under docker/ configure the open-source Eclipse Mosquitto broker (EPL-2.0) for local testing only — they are not part of the MCP server itself.

Source: sparkplug-b/README.md at commit 5a985b6

Tools

SourceWeft has not started this package in its sandbox yet, so its tools are not known.

Version history

v0.1.0LatestSep 16, 2026

Score

50% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

Reached in the last 30 days25 pts
Keep the endpoint answering the MCP handshake; SourceWeft probes it every 30 days.
Auth declared10 pts
Declare the credential headers in the registry entry, or keep the endpoint answering the probe so its auth can be classified.
Tools listed15 pts
Answer tools/list without a credential, or ship a package that starts in a sandbox without one.
DescriptionRequired15 pts
Logo10 pts
Documentation15 pts
License10 pts