Works through Micro-Cap's own batch mode (MC12 @batch.bat) — headless, no GUI automation, no modification of the program.

What it does

🔧 Builds circuits from scratch — 8 stage generators (common-emitter, follower, MOSFET, differential pair, current mirror, cascode, op-amp, RLC) with automatic biasing. Each is checked against theory: gain, operating point, resonance.

📊 Simulates — transient / AC / DC / distortion / stability, operating point, sweeps. Complex output as {re, im}, solver diagnostics.

🎨 Draws — renders a .CIR to SVG 1:1 with Micro-Cap: the native symbols from MC's shape library, the dot grid, every rotation and reflection, the label layout. Overlays operating-point voltages. MC's /IC can't export a drawing in batch — this can.

Install

Needs Windows, Python 3.11+ and an installed copy of Micro-Cap 12 (freeware). Nothing to clone — point your MCP client at it and uvx fetches the package:

{
  "mcpServers": {
    "microcap": {
      "command": "uvx",
      "args": ["microcap-mcp"],
      "env": { "MICROCAP_HOME": "E:/Tools/MC12" }   // only if the scan misses it
    }
  }
}

The driver looks for Micro-Cap in the usual places; set MICROCAP_HOME to the folder holding mc12_64.exe if yours lives elsewhere.

git clone https://github.com/monoxide-xen/microcap-mcp
cd microcap-mcp
uv sync

{
  "mcpServers": {
    "microcap": {
      "command": "uv",
      "args": ["--directory", "C:/path/to/microcap-mcp", "run", "microcap-mcp"]
    }
  }
}

Tools

Plus resources microcap://guide and microcap://domains and an analyse_circuit prompt — so the agent doesn't let Micro-Cap silently mislead it.

Tests

uv run pytest        # 138 unit with no Micro-Cap; +30 integration against physics (needs MC)

Without Micro-Cap the integration tests skip, so CI stays green.

How it works

• Micro-Cap notes — behaviour that is not in the manual, and in places contradicts it.
• eval/harness.py — runs all ~490 shipped circuits and buckets the failures by cause (88% answer today).

Licence

MIT for the code in this repository. Micro-Cap 12 belongs to Spectrum Software — not included, redistributed or modified: this uses its documented CLI.

mcp-name: io.github.monoxide-xen/microcap-mcp