spicebridge
MCP server that gives AI assistants direct access to ngspice circuit simulation: design, simulate, and verify circuits through natural language, plus SPICE-to-KiCad export.
What it does and how it connects
SPICEBridge is an MCP server that gives language models direct access to SPICE circuit simulation via ngspice. A user describes a circuit in plain English and the AI handles netlist generation, simulation, measurement and spec verification. It ships 28 tools covering the full circuit design workflow and 11 built-in templates with automatic component value calculation in the E24 series.
Simulation covers AC sweep, transient and DC operating point, with measurement of bandwidth, gain, DC levels, transient metrics and power, plus Monte Carlo and worst-case analysis under component tolerances, multi-stage composition with automatic port mapping, and a model wizard that generates SPICE .lib models from datasheet parameters. Spec verification compares results against design targets.
The server also exports .kicad_sch schematics, has an interactive schematic viewer in the browser, and offers a cloud setup wizard that deploys a public MCP endpoint with Cloudflare tunnels. It installs with pip install spicebridge, needs Python 3.10 or newer and ngspice installed and on PATH, and runs locally over stdio or over streamable HTTP.
What engineers report
Exported .kicad_sch files fail to load in KiCad. The reporter lists four independent defects, reproduced with a minimal Sallen-Key low-pass netlist.
2026-10-25Read the original
Alternatives
Compare side by side- dsh-kicad
A DeepSeek Harness plugin for AI-driven PCB design in KiCad with ngspice simulation built in, rather than an MCP server dedicated to simulation.
- Fenolite
Headless Python PCB automation with an agent guide, rather than an MCP server for ngspice simulation.
- kicad-mcp (blwfish)
A community MCP server letting agents drive full KiCad PCB workflows, rather than an MCP server for ngspice simulation.
- ngspice
The open-source SPICE simulator itself, driven by netlists and the command line, rather than an MCP server wrapping it for agents.
Recurring errors it addresses
Error Index entries this tool is built to reduce or work around.
- With a small Sallen-Key netlist, the SPICE-to-KiCad exporter produced a malformed .kicad_sch (unclosed polyline, wrong pin/instance order, netlist comments parsed as components); the fix PR found seven more defects after load, including pins snapped to the wrong grid, wrong rotation direction, GND symbols 2.54 mm off their pins, SPICE node order sent to the wrong pins, and L-shaped wires shorting nets.Error Index
- SPICEBridge, an MCP server letting an agent simulate circuits in ngspice, shipped both built-in Sallen-Key filter templates wired for positive feedback; nobody saw it because the ideal op-amp model has no dynamics, but with a single-pole op-amp model the output ran to 7e297 V and ngspice aborted, and the Butterworth values were also off.Error Index
- The SPICE-to-KiCad MCP server had three separate schematic drawers for one netlist: the KiCad export was right, but the draw_schematic tool chained parts in netlist order and connected C1 to the wrong net and drew the controlled source as a resistor, while the web viewer drew that source as an empty box with wires through it.Error Index
- A SPICE-to-KiCad exporter used Device:Q_NPN_BCE and similar names that no longer exist in KiCad's library; files still opened because symbols were embedded, so the drift only showed up as ERC lib_symbol_issues, and MOSFET templates were also missing channel connections.Error Index
- Same SPICE-to-KiCad export, more gaps: controlled sources, JFETs and behavioral sources were all drawn as plain resistors, often with only 2 of their 4 nodes wired; subcircuits with more than 5 nodes lost the extra nodes; coupled inductors became a resistor between two nets that do not exist; behavioral expressions like VALUE={V(a)*2} were taken as node names.Error Index
Sources
Not verified
- Pricing: none stated on the repo; the package is free open source.
- Version note: the latest GitHub release is v1.1.14 from 2026-02-13, but issue #5 reports version 1.3.0 on PyPI, so the PyPI release is newer than the latest GitHub release tag.
- The last push to the repo is 2026-04-06, so the repo has not been pushed in seven months.
Last verified November 6, 2026. Listings are informational. The evidence score measures public, verifiable evidence and is not an endorsement or a compatibility claim.