KiCAD-MCP-Server

This Python/TypeScript server remains fully open (MIT) and maintained.

A Model Context Protocol (MCP) server that enables AI assistants like Claude to interact with KiCAD for PCB design automation. Built on the MCP 2025-06-18 specification, this server provides comprehensive tool schemas and real-time project state access for intelligent PCB design workflows.

- 169 tools across 15 categories with JSON Schema validation
- Keyword tool discovery viasearch_tools/get_category_tools
- 8 dynamic resources exposing project state
- Complete schematic workflow with 27 tools and dynamic symbol loading (~10,000 symbols)
- Freerouting autorouter integration (Java, Docker, or Podman)
- Custom footprint and symbol creation tools
- JLCPCB parts integration with 2.5M+ component catalog and local library search
- Datasheet enrichment via LCSC
- Full MCP 2025-06-18 protocol compliance
- Cross-platform support (Linux, Windows, macOS)
- Real-time KiCAD UI integration via IPC API (experimental)
- Comprehensive error handling and logging

Try out Arduino MCP - now you can get Claude to help in the IDE, real time!:

The Node-Python protocol had no request IDs: after one timeout, the next command was silently resolved with thepreviouscommand's late result, and every response after that was off by one. Tool calls now carry an ID that Python echoes back; stale responses are discarded instead of mis-delivered (#373). The MCP transport also connects before Python spawns, so clients no longer stack up against a silent server for up to two minutes during pcbnew warm-up (#377).

add_symbol_propertydropped a closing paren on every call and could splice a unit symbol into a top-level sibling (#362, @karu2003). And S-expression escaping is now symmetric: reads (#336) and writes (#324) share one escape-aware implementation, so a property value containing\"survives a round-trip — 419 of KiCad's own stock symbol files carry such values.

- Validation:validate_schematic,validate_symbol_library— locate structural damage with line/column, confirmed viakicad-clion a copy.
- Library tables:list_library_table,remove_library_table_entry,set_library_table_uri— the missing CRUD aroundregister__library.
- Symbol editing:set_symbol_pin_type(bulk pin type fixes with dry-run),find_duplicate_symbols(the same part stored twice).
- Back-annotation:backannotate_footprints— PCB footprint choices flow back to the schematic, the reverse ofsync_schematic_to_board.

- New projects start blank (no_TEMPLATE_symbols leaked into user files).
- .kicad_profiles match what KiCad itself writes.
- Format version20260101ensures all KiCad 10.0.x builds can open generated schematics.

- Derived symbols in.kicad_symdirlibraries resolve their parent from sibling shards.
- Unified install discovery finds relocated Windows installs via registry.
- User env-var placeholders fromkicad_common.jsonare resolved in library paths.
- Phantom cross-unit pin reports inget_wire_connectionsare eliminated.

Schematic corruption on KiCad 10 — both mechanisms fixed

- Complete instance blocks: placed components now carry the real project name, root-sheet uuid path, per-pin uuid entries (ERC can bind wires to pins), and the full KiCad 10 field set — verified byte-equivalent to what eeschema itself writes. Previously, dragging or editing a placed symbol could crash KiCad.
- Canonical multi-line writes: schematic tools no longer minify the whole file onto one line. Tool writes now match eeschema's "Save" byte-for-byte, with a self-check on every write that can never corrupt data. Already- minified files are repairable withscripts/kicad_sch_reformat.py.

- Backend session pinning: a loaded project stays on one backend (SWIG or IPC) for its whole lifecycle — saves can no longer silently route to a stale GUI board and lose your edits.
- External-edit guard:save_projectrefuses to overwrite a board file whose contents changed on disk since load (passforce: trueto override).
- close_project(new tool): release the project so files can be edited directly, then reopen — no more restart choreography.

- kicad-cliand 7-Zip are resolved from their install locations even when not on PATH — un-breaking exports, ERC/DRC, netlists, board views, and the JLCPCB database download, each with actionable errors when truly missing.

- suggest_placement: connectivity-driven PCB placement optimizer (dry-run by default, deterministic).
- suggest_schematic_declutter: re-orients overlapping net labels without touching connectivity.

New Tools: FFC/Ribbon Cable Passthrough Workflow

A complete workflow for designing passthrough adapter boards (e.g. Raspberry Pi CSI cable adapters) is now supported:
- connect_passthrough— wires all pins of one connector to the matching pins of another in the schematic (J1 pin N → J2 pin N, auto-named nets).
- sync_schematic_to_board— imports the net assignments into the PCB.
- route_pad_to_pad— routes each connection with automatic via insertion when pads are on opposite copper layers.
- snapshot_project— saves a named checkpoint into<project>/snapshots/.

- Via insertion for B.Cu footprints—route_pad_to_padnow correctly detects when a footprint is on B.Cu and inserts the required via. (KiCAD 9 SWIG returnedF.Cufor all SMD pads regardless of layer — fixed.)
- Board outline rounded corners—add_board_outlinenow correctly appliescornerRadiuswhenshape="rounded_rectangle".
- B.Cu placement hang— placing a footprint on B.Cu no longer causes a ~30s freeze in KiCAD 9.

SetKICAD_MCP_DEV=1in your Claude Desktop MCP environment to automatically save the MCP session log into the project'slogs/folder on everyexport_gerberandsnapshot_projectcall. Useful for debugging and for attaching to GitHub issues.

"env": { "KICAD_MCP_DEV": "1" }

Privacy warning:The session log contains your full tool call history (including file paths and design details).Review or deletelogs/before sharing a project directory publicly.

Critical Schematic Workflow Fix + Complete Wiring System (Issue #26)

The schematic workflow was completely broken in previous versions -this is now fixed AND dramatically enhanced!

- create_projectonly created PCB files, no schematics
- add_schematic_componentcalled non-existent API methods
- Schematics couldn't be created or edited at all
- Only 13 component types available (severe limitation)
- No working wire/connection functionality

- create_projectnow creates both .kicad_pcb and .kicad_sch files
- Added pre-configured template schematics with 13 common component types
- Rewrote component placement to use properclone()API

Phase 2: Dynamic Symbol Loading (BREAKTHROUGH!)

- Access to ALL ~10,000 KiCad symbolsfrom standard libraries
- Automatic detection and dynamic loading from.kicad_symlibrary files
- Zero configuration required - just specify library and symbol name
- Seamless integration with existing MCP tools
- Full S-expression parsing and injection system

Phase 3: Intelligent Wiring System (NEW in v2.1.0)

- Automatic pin location discoverywith rotation support (0°, 90°, 180°, 270°)
- Smart wire routing(direct, orthogonal horizontal-first, orthogonal vertical-first)
- Power symbol support(VCC, GND, +3V3, +5V, etc.)
- Wire graph analysis- geometric tracing for net connectivity
- Net label management(local, global, hierarchical labels)
- Netlist generationwith accurate component/pin connections

Technical Architecture:The kicad-skip library cannot create symbols or wires from scratch. We implemented a comprehensive solution:
- Static Templates:13 pre-configured symbols (R, C, L, LED, etc.) for instant use
- Dynamic Loading:On-demand injection of ANY symbol from KiCad libraries:

- Parse.kicad_symlibrary files using S-expression parser
- Inject symbol definition into schematic'slib_symbolssection
- Create offscreen template instance
- Reload schematic so kicad-skip sees new template
- Clone template to create actual component

We are currently implementing and testing the KiCAD 9.0 IPC API for real-time UI synchronization:

- Changes made via MCP tools appear immediately in the KiCAD UI
- No manual reload required when IPC is active
- Hybrid backend: uses IPC when available, falls back to SWIG API
- IPC runtime reconnect: if MCP has fallen back to SWIG, IPC-capable board tools retry IPC after KiCAD launches instead of staying on SWIG for the entire session
- 20+ commands now support IPC including routing, component placement, and zone operations

Note: IPC features are under active development and testing. Enable IPC in KiCAD via Preferences > Plugins > Enable IPC API Server.

We've implemented an intelligent tool router to keep AI context efficient while maintaining full functionality:

- 22 direct toolsalways visible for high-frequency operations
- 113 routed toolsorganized into 14 categories (board, component, export, drc, schematic, library, symbol_pins, schematic_hierarchy, schematic_layout, schematic_batch, routing, autoroute, validation, parts-registry)
- 4 router toolsfor discovery and execution:

- list_tool_categories- Browse all available categories
- get_category_tools- View tools in a specific category
- search_tools- Find tools by keyword
- execute_tool- Run any tool with parameters

Why this matters:By organizing tools into discoverable categories, Claude can intelligently find and use the right tool for your task without loading all 122 tool schemas into every conversation. This reduces context consumption while maintaining full access to all functionality.

Usage is seamless:Just ask naturally - "export gerber files" or "add mounting holes" - and Claude will discover and execute the appropriate tools automatically.

- Real-time pricing with quantity breaks (1+, 10+, 100+, 1000+)
- Stock availability checking
- Basic vs Extended library type identification (Basic = free assembly)
- Intelligent cost optimization with alternative part suggestions
- Package-to-footprint mapping for KiCAD compatibility
- Parametric search by category, package, manufacturer
- Local SQLite database for fast offline searching
- No API credentials required for local library search

Why this matters:JLCPCB offers PCB assembly services where Basic parts have no assembly fee, while Extended parts charge $3 per unique component. This integration helps you find the cheapest components with the best availability, potentially saving hundreds of dollars on assembly costs for production runs.

Every tool now includes complete JSON Schema definitions with:

- Detailed parameter descriptions and constraints
- Input validation with type checking
- Required vs. optional parameter specifications
- Enumerated values for categorical inputs
- Clear documentation of what each tool does

Access project state without executing tools: