TiaMcp

MCP server for Siemens TIA Portal V21+ projects — reads and writes directly to TIA Portal via the Openness API, designed for a fast, LLM- and human-friendly workflow.

Special features that make TiaMcp fast for LLM’s and human-readable friendly:

• STL is read/written as text AWL
• PLC tables are converted to/from Excel-compatible CSV
• HMI tables are converted to/from Excel-compatible CSV
• HMI alarms are converted to/from Excel-compatible CSV
• GRAPH is converted to/from compact text DSL (Domain Specific Language)

Format reference

Each item line of list_project ends with the formats it can be read in, e.g. tag table 'Tags' [csv, xml]; pass such a line to read_source_tree to read those formats. A write uses the one format whose files were edited, and refuses an item edited in two.

All source is read and written as files in a source tree on disk, so an LLM reads only what it needs and edits with small diffs instead of passing whole blocks through its context.

Prerequisites

• TIA Portal V21 installed, with Openness access enabled for your Windows user (Openness API group membership).
• .NET Framework 4.8.

Building

dotnet build TiaMcp.sln

Produces src\TiaMcp.Host\bin\Debug\net48\TiaMcp.Host.exe, the MCP stdio server entry point. dotnet test TiaMcp.sln runs the unit tests (no TIA Portal needed).

Registering with Claude Code

Copy .mcp.json.example to .mcp.json and point command at wherever you extracted or built TiaMcp.Host.exe:

{
  "mcpServers": {
    "tia": {
      "command": "C:\\path\\to\\TiaMcp.Host.exe",
      "args": []