SPICE simulation through an MCP server and an in-process Python API for LTspice and ngspice. Supports schematic editing, sweeps, Monte Carlo analysis, and structured measurements.
Listed on its own since 2026-09-26. Until then it was part of circuit-mcp, where its earlier checks remain.
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# ltspice-mcp <!-- mcp-name: io.github.cognitohazard/ltspice-mcp --> > **Work in progress.** Expect breaking changes across versions. ltspice-mcp is an MCP server that lets an AI assistant simulate circuits with LTspice or ngspice and edit LTspice schematics. Its goals are speed, correctness, token efficiency and clean schematics. The assistant uses ready-made, well-tested tools, which know the quirks of SPICE and of each simulator, instead of improvised scripts. Mechanical checks catch common errors before a file is written or run, and direct the assistant's attention to the right place. Layout is left to the assistant's judgment, not an auto-router. Results come back as named numbers, such as a phase margin, instead of waveforms to read. To see a waveform yourself, ask for an interactive chart, shown in the chat where the client supports it. Sweeps, corners and Monte Carlo take one call and run as background jobs that survive a restart and can be replayed. With LTspice 26.1 or later on Windows, you and the assistant can edit the same open schematic ([Working with LTspice open](https://github.com/cognitohazard/ltspice-mcp/blob/master/docs/USAGE.md#working-with-ltspice-open)). Everything the tools do is also available from Python, as the `ltspice_mcp.api` package. The server is built on [spicelib](https://github.com/nunobrum/spicelib). ## Quick start **Claude Code:** ``` /plugin marketplace add cognitohazard/ltspice-mcp /plugin install ltspice-mcp ``` **Claude Desktop:** build the extension in [`packaging/mcpb/`](https://github.com/cognitohazard/ltspice-mcp/tree/master/packaging/mcpb) and drag the `.mcpb` file onto Claude Desktop. The extension asks for an optional sandbox folder. If you leave it blank, there is no sandbox. **Any other MCP client** ([Cursor](https://cursor.com/docs/mcp), [Windsurf](https://docs.devin.ai/desktop/cascade/mcp), [Gemini CLI](https://google-gemini.github.io/gemini-cli/docs/tools/mcp-server.html), [Continue](https://docs.co…
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