Industrial MCP servers that expose writes
As of 3 November 2026, 5 of 21 industrial MCP servers expose write tools by default. Nothing has to be armed before a client can call the write.
- AWS IoT SiteWise MCP ServerAmazon Web Services
AWS Labs MCP server for SiteWise asset models, time series, and related industrial data in an AWS account.
Open-source server in awslabs/mcp. It calls SiteWise APIs in your account, so IAM is the real permission boundary and SiteWise itself is a paid AWS service. It does not speak Modbus or OPC UA; something else has to land data in SiteWise first. Asset writes and ingestion tools are part of the surface. Keep the IAM policy narrower than the demo.
Verified 2026-11-03
- FieldWorks protocol adaptersFieldWorks · MQTT / Sparkplug, OPC UA
Rust MCP adapters with one tool surface. MQTT and OPC UA are implemented; Modbus, DNP3, and EtherNet/IP are stubs.
Apache-2.0 workspace. mqtt-mcp and opcua-mcp are marked complete. modbus-mcp, dnp3-mcp, ethernetip-mcp, and aveva-mcp are marked stubs, so they are not listed as protocols here. The MQTT adapter is MQTT 3.1.1/5, not Sparkplug B. The shared surface includes setpoint writes. Check topology.yaml before connecting anything real.
Verified 2026-11-03
- kukapay/modbus-mcpkukapay · Modbus
Python Modbus MCP server for TCP, UDP, or serial, including write tools in the default set.
MIT. Tools cover holding registers, coils, and input registers. Writes are part of the advertised surface, configured by host environment variables. There is no register map, so the model sees raw values. Do not aim it at a production gateway.
Verified 2026-11-03
- kukapay/opcua-mcpkukapay · OPC UA
Small Python OPC UA MCP server with read, write, browse, and batch tools turned on together.
MIT. The published tool list includes write_opcua_node and a multi-write, with no documented allowlist or arming switch. Fine against a simulator. A poor choice pointed at a production server. Prefer a read-only server (Proxus, or IndustriConnect in its default profile) if you do not already have a write procedure.
Verified 2026-11-03
- OPC Foundation OPC UA MCPOPC Foundation · OPC UA
Official .NET tool that exposes OPC UA services to MCP clients, with selectable tool profiles.
Package OPCFoundation.NetStandard.Opc.Ua.Mcp, run with dotnet tool exec or a global install as opcua-mcp. Profiles select a bounded tool catalog (core, machinery, alarms, history, and others). The default profile is broad, and UA services include writes, so treat the default as able to write. The repository is under the OPC Foundation MIT license. A WoT profile can also reach HTTP, MQTT, and Modbus TCP; that is optional and not the reason to install it.
Verified 2026-11-03
This is not a safety case. The counts describe the public tool surface on each entry's last-verified date. They do not certify a server, a model, a network, or a plant. A gated write is still a write once you arm it.