Use PraxisCAD with a local LLM

How it fits together

PraxisCAD offers its tools through MCP. A local model cannot use MCP by itself, so you need three things on your computer: PraxisCAD, a local model runtime (Ollama or LM Studio) serving a model that supports tool calling, and an MCP-capable client that connects the two. LM Studio can act as that client itself. With Ollama, use any MCP-capable client that can talk to Ollama.

Everything runs locally and works offline. For what the app itself sends over the network, see the privacy statement.

Ollama

1. Install and open PraxisCAD, and keep it running.
2. Install Ollama and pull a model that supports tool calling (see Choosing a model).
3. Pick an MCP-capable client that supports Ollama as its model provider, and add the PraxisCAD server to its MCP settings using the configuration below.
4. Restart the client and ask: “Make a 60×40×10 mm plate with four 5 mm holes.”

LM Studio

1. Install and open PraxisCAD, and keep it running.
2. In LM Studio, download a model that supports tool use and load it.
3. Open LM Studio's MCP settings and add the PraxisCAD server using the configuration below.
4. Start a chat with the model and ask for a part.

Server configuration

The same stdio entry works in any MCP client. No URL or port is needed.

{
  "mcpServers": {
    "praxiscad": {
      "command": "/Applications/PraxisCAD.app/Contents/MacOS/praxiscad-mcp",
      "args": []
    }
  }
}

{
  "mcpServers": {
    "praxiscad": {
      "command": "C:\\Users\\YOU\\AppData\\Local\\PraxisCAD\\praxiscad-mcp.exe",
      "args": []
    }
  }
}

Local-model mode

Small models struggle with a long tool list. The local-model mode gives them a smaller tool set (the core profile: 15 tools, about 5k tokens together with a compact skill, instead of about 35k) plus a compact skill, praxiscad-local, made for small models. It is available since PraxisCAD 0.4.4.

To turn it on, set PRAXISCAD_MCP_PROFILE=core in the client's MCP configuration:

{
  "mcpServers": {
    "praxiscad": {
      "command": "/Applications/PraxisCAD.app/Contents/MacOS/praxiscad-mcp",
      "args": [],
      "env": {
        "PRAXISCAD_MCP_PROFILE": "core"
      }
    }
  }
}

Add the praxiscad-local skill from the skill repo, or from praxiscad-local-skill.zip on the latest release.

On an M2 Pro Mac with 16 GB, gemma4:e4b in this mode built the cup (with STEP export) 4 of 4 times and the plate with holes 2 of 4 times, and parameter edits worked whenever the part existed. Without the mode, small models could only edit and measure.

Choosing a model

Look for a model that supports tool calling and a long context window. Larger models follow multi-step CAD workflows more reliably than small ones. Models that accept images can look at PraxisCAD's renders; text-only models still get every number (size, volume, mass).

Works with any MCP-capable AI, cloud or local. You choose. Results scale with your model: cloud models build complex parts and assemblies.

Simple parts work most of the time on small local models. For complex parts, use a larger local model (32 GB+) or a cloud model.

Tested on an M2 Pro Mac with 16 GB in October 2026 with gemma4:e4b and qwen3:8b.

Also add the PraxisCAD skill: its instructions help smaller models make fewer mistakes.

Questions or problems?

Write to support@praxiscad.com.