KiCAD-MCP-Server/CHANGELOG.md

Changelog

All notable changes to the KiCAD MCP Server project are documented here.

[2.2.1-alpha] - 2026-02-28

New MCP Tools

• edit_schematic_component – Update properties of a placed symbol in-place (footprint, value, reference rename). More efficient than delete + re-add: preserves position and UUID.

Bug Fixes

• add_schematic_component: footprint parameter was accepted but silently ignored – the value was never passed through to DynamicSymbolLoader.add_component() / create_component_instance(). All newly placed symbols always had an empty Footprint field. Fix: added footprint: str = "" to both functions and threaded it through every call site including the TypeScript tool schema.

• delete_schematic_component: only deleted the first matching instance when duplicate references existed (e.g. after an aborted add attempt). Root cause: loop used break after the first match. Fix: collect all matching blocks first, then delete them all back- to-front (to preserve line indices). Response now includes deleted_count.

• templates/*.kicad_sch, project.py, schematic.py: Update KiCAD schematic format version from 20230121 (KiCAD 7) to 20250114 (KiCAD 9). The MCP server targets KiCAD 9 exclusively (pcbnew.pyd compiled for KiCAD 9.0, Python 3.11.5) – generating files in an outdated format caused a spurious "This file was created with an older KiCAD version" warning on every newly created schematic.

• template_with_symbols_expanded.kicad_sch: Remove 13 corrupt _TEMPLATE_* placed-symbol blocks with (lib_id -100) – an integer caused by old sexpdata serializer (same bug PR #40 fixed for the add path). KiCAD crashed with a null-pointer when selecting these symbols. They appeared as grey _TEMPLATE_R?, _TEMPLATE_U_REG? etc. labels far outside the sheet boundary (~5000mm off-sheet).

  Discovered via: live testing on a real JLCPCB/KiCAD 9 project. Affected users: schematics created from this template before this fix contain the same corrupt blocks – remove all (symbol (lib_id -100) ...) blocks whose Reference starts with _TEMPLATE_.

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[2.2.0-alpha] - 2026-02-27

New MCP Tools (TypeScript layer – previously Python-only)

Routing tools:

• delete_trace - Delete traces by UUID, position or net name
• query_traces - Query/filter traces on the board
• get_nets_list - List all nets with net code and class
• modify_trace - Modify trace width or layer
• create_netclass - Create or update a net class
• route_differential_pair - Route a differential pair between two points
• refill_zones - Refill all copper zones ⚠️ SWIG segfault risk, prefer IPC/UI

Component tools:

• get_component_pads - Get all pad data for a component
• get_component_list - List all components on the board
• get_pad_position - Get absolute position of a specific pad
• place_component_array - Place components in a grid array
• align_components - Align components along an axis
• duplicate_component - Duplicate a component with offset

Bug Fixes

• routing.py: Fix SwigPyObject UUID comparison (str() → m_Uuid.AsString())
• routing.py: Fix SWIG iterator invalidation after board.Remove() by snapshotting list(board.Tracks())
• routing.py: Add board.SetModified() + track = None after Remove() to prevent dangling SWIG pointer crashes
• routing.py: Per-track try/except in query_traces() to skip invalid objects after bulk delete
• routing.py: Add missing return statement (mypy)
• library.py: Fix search_footprints parameter mapping (search_term → pattern)
• library.py: Fix field access (fp.name → fp.full_name)
• library.py: Accept both pattern and search_term parameter names
• library.py: Fix loop variable shadowing Path object (mypy)
• design_rules.py: Add type annotation for violation_counts (mypy)

New MCP Tools (cont.)

Datasheet tools:

• get_datasheet_url - Return LCSC datasheet PDF URL and product page URL for a given LCSC number (e.g. C179739 → https://www.lcsc.com/datasheet/C179739.pdf). No API key required – URL is constructed directly from the LCSC number.
• enrich_datasheets - Scan a .kicad_sch file and write LCSC datasheet URLs into every symbol that has an LCSC property but an empty Datasheet field. After enrichment the URL appears natively in KiCAD's symbol properties, footprint browser and any other tool that reads the standard KiCAD Datasheet field. Supports dry_run=true for preview without writing. Implementation: python/commands/datasheet_manager.py (text-based, no skip writes)

Schematic tools:

• delete_schematic_component - Remove a placed symbol from a .kicad_sch file by reference designator (e.g. R1, U3).

Bug Fixes (cont.)

• schematic.ts / kicad_interface.py: Fix missing delete_schematic_component MCP tool.

  Root cause (two separate issues):

  1. No MCP tool named delete_schematic_component existed. Claude had no way to call it, so any "delete schematic component" request fell through to the PCB-only delete_component tool, which searches pcbnew.BOARD and always returned "Component not found" for schematic symbols.
  2. component_schematic.py::remove_component() still used skip for writes. PR #40 rewrote DynamicSymbolLoader (add path) to avoid skip-induced schematic corruption, but remove_component (delete path) was not touched by that PR.

  Fix:

  • Added delete_schematic_component to the TypeScript tool layer (schematic.ts) with clear docstring distinguishing it from the PCB delete_component.
  • Implemented _handle_delete_schematic_component in kicad_interface.py using direct text manipulation (parenthesis-depth tracking, same approach as PR #40). Does not call component_schematic.py::remove_component() at all.
  • Error message explicitly guides the user when the wrong tool is used: "note: this tool removes schematic symbols, use delete_component for PCB footprints"

Additional Bug Fixes

• connection_schematic.py / kicad_interface.py: Fix generate_netlist missing schematic_path parameter – without it get_net_connections always fell back to proximity matching which only returns one connection per component (first wire hit, then break). PinLocator was never invoked. Fix: added schematic_path: Optional[Path] to generate_netlist signature and threaded it through to get_net_connections, and updated _handle_generate_netlist in kicad_interface.py to pass schematic_path.
• server.ts: Fix KiCAD bundled Python (3.11.5) not being selected on Windows – the detection condition process.env.PYTHONPATH?.includes("KiCad") was fragile and failed in some environments, causing System Python 3.12 to be used instead. Since pcbnew.pyd is compiled for KiCAD's Python 3.11.5, this resulted in No module named 'pcbnew'. Fix: removed the condition, KiCAD bundled Python is now always preferred on Windows when it exists at C:\Program Files\KiCad\9.0\bin\python.exe. Also added KICAD_PYTHON to claude_desktop_config.json as explicit override.
• pin_locator.py: Fix generate_netlist timeout – get_pin_location and get_all_symbol_pins called Schematic(schematic_path) on every single pin lookup, causing O(nets × components × pins) schematic file loads (e.g. 400+ loads for a medium schematic). Fix: added _schematic_cache dict to PinLocator.__init__, schematic is now loaded once per path and reused.

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[2.1.0-alpha] - 2026-01-10

Phase 1: Intelligent Schematic Wiring System - Core Infrastructure

Major Features:

• Automatic pin location discovery with rotation support
• Smart wire routing (direct, orthogonal horizontal/vertical)
• Net label management (local, global, hierarchical)
• S-expression-based wire creation
• Professional right-angle routing

New Components:

• python/commands/wire_manager.py - S-expression wire creation engine
• python/commands/pin_locator.py - Intelligent pin discovery with rotation
• Updated python/commands/connection_schematic.py - High-level connection API
• docs/SCHEMATIC_WIRING_PLAN.md - Implementation roadmap

MCP Tools Enhanced:

• add_schematic_wire - Create wires with stroke customization
• add_schematic_connection - Auto-connect pins with routing options (NEW)
• add_schematic_net_label - Add labels with type and orientation control (NEW)
• connect_to_net - Connect pins to named nets (ENHANCED)

Technical Implementation:

• Rotation transformation matrix for pin coordinates
• S-expression injection for guaranteed format compliance
• Pin definition caching for performance
• Orthogonal path generation for professional schematics

Testing:

• End-to-end integration test: 100% passing
• MCP handler integration test: 100% passing
• Pin discovery with rotation: Verified working
• KiCad-skip verification: All wires/labels correctly formed

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Phase 2: Power Nets & Wire Connectivity - COMPLETE

Major Features:

• Power symbol support (VCC, GND, +3V3, +5V, etc.) via dynamic loading
• Wire graph analysis for net connectivity tracking
• Geometric wire tracing with tolerance-based point matching
• Accurate netlist generation with component/pin connections
• Critical template mapping bug fixes

Updates:

• connect_to_net() - Migrated to WireManager + PinLocator
• get_net_connections() - Complete rewrite with geometric wire tracing
• generate_netlist() - Now uses wire graph analysis for connectivity
• get_or_create_template() - Fixed special character handling, auto-reload after dynamic loading
• add_component() - Fixed template lookup with symbol iteration

Bug Fixes:

• CRITICAL: Template mapping after dynamic symbol loading
• Special character handling in symbol names (+ prefix in +3V3, +5V)
• Schematic reload synchronization after S-expression injection
• Multi-format template reference detection

Wire Graph Analysis Algorithm:

1. Find all labels matching target net name
2. Trace wires connected to label positions (point coincidence)
3. Collect all wire endpoints and polyline segments
4. Match component pins at wire connection points using PinLocator
5. Return accurate component/pin connection pairs

Technical Implementation:

• Tolerance-based point matching (0.5mm for grid alignment)
• Multi-segment wire (polyline) support
• Rotation-aware pin location matching via PinLocator
• Fallback proximity detection (10mm threshold)
• Template existence checking via symbol iteration (handles special characters)

Testing:

• Power symbols: 4/4 loaded (VCC, GND, +3V3, +5V)
• Components: 4/4 placed
• Connections: 8/8 created successfully
• Net connectivity: 100% accurate (VCC: 2, GND: 4, +3V3: 1, +5V: 1)
• Netlist generation: 4 nets with accurate connections
• Comprehensive integration test: 100% PASSING

Commits:

• c67f400 - Updated connect_to_net to use WireManager
• b77f008 - Fixed template mapping bug (critical)
• a5a542b - Implemented wire graph analysis

Addresses:

• Issue #26 - Schematic workflow wiring functionality (Phase 2)

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Phase 2: JLCPCB Integration Complete

Major Features:

• ✅ Complete JLCPCB parts integration via JLCSearch public API
• ✅ Access to ~100k JLCPCB parts catalog
• ✅ Real-time stock and pricing data
• ✅ Parametric component search
• ✅ Cost optimization (Basic vs Extended library)
• ✅ KiCad footprint mapping
• ✅ Alternative part suggestions

New Components:

• python/commands/jlcsearch.py - JLCSearch API client (no auth required)
• python/commands/jlcpcb_parts.py - Enhanced with import_jlcsearch_parts()
• docs/JLCPCB_INTEGRATION.md - Comprehensive integration guide

MCP Tools Available:

• download_jlcpcb_database - Download full parts catalog
• search_jlcpcb_parts - Parametric search with filters
• get_jlcpcb_part - Part details + footprint suggestions
• get_jlcpcb_database_stats - Database statistics
• suggest_jlcpcb_alternatives - Find similar/cheaper parts

Technical Improvements:

• SQLite database with full-text search (FTS5)
• Package-to-footprint mapping for standard SMD packages
• Price comparison and cost optimization algorithms
• HMAC-SHA256 authentication support (for official JLCPCB API)

Testing:

• All integration tests passing
• Database operations validated
• Live API connectivity confirmed
• End-to-end MCP tool testing complete

Documentation:

• Complete API reference with examples
• Package mapping tables (0402, 0603, 0805, SOT-23, etc.)
• Best practices guide
• Troubleshooting section

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[2.1.0-alpha] - 2025-11-30

Phase 1: Schematic Workflow Fix

Critical Bug Fix:

• ✅ Fixed completely broken schematic workflow (Issue #26)
• Created template-based symbol cloning approach
• All schematic tests now passing

Root Cause:

• kicad-skip library limitation: cannot create symbols from scratch, only clone existing ones

Solution:

• Template schematic with cloneable R, C, LED symbols
• Updated create_project to create both PCB and schematic
• Rewrote add_schematic_component to use clone() API
• Proper UUID generation and position setting

Files Modified:

• python/commands/project.py - Now creates schematic files
• python/commands/schematic.py - Uses template approach
• python/commands/component_schematic.py - Complete rewrite

Files Created:

• python/templates/template_with_symbols.kicad_sch
• python/templates/empty.kicad_sch
• docs/SCHEMATIC_WORKFLOW_FIX.md

Testing:

• Created comprehensive test suite
• All 7 tests passing
• KiCad CLI validation successful

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[2.0.0-alpha] - 2025-11-05

Router Pattern & Tool Organization

Major Architecture Change:

• Implemented tool router pattern (70% context reduction)
• 12 direct tools, 47 routed tools in 7 categories
• Smart tool discovery system

New Router Tools:

• list_tool_categories - Browse available categories
• get_category_tools - View tools in category
• search_tools - Find tools by keyword
• execute_tool - Run any routed tool

Benefits:

• Dramatically reduced AI context usage
• Maintained full functionality (64 tools)
• Improved tool discoverability
• Better organization for users

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[2.0.0-alpha] - 2025-11-01

IPC Backend Integration

Experimental Feature:

• KiCad 9.0 IPC API integration for real-time UI sync
• Changes appear immediately in KiCad (no manual reload)
• Hybrid backend: IPC + SWIG fallback
• 20+ commands with IPC support

Implementation:

• Routing operations (interactive push-and-shove)
• Component placement and modification
• Zone operations and fills
• DRC and verification

Status:

• Under active development
• Enable via KiCad: Preferences > Plugins > Enable IPC API Server
• Automatic fallback to SWIG when IPC unavailable

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[2.0.0-alpha] - 2025-10-26

Initial JLCPCB Integration (Local Libraries)

Features:

• Local JLCPCB symbol library search
• Integration with KiCad Plugin and Content Manager
• Search by LCSC part number, manufacturer, description

Credit:

• Contributed by @l3wi

Components:

• python/commands/symbol_library.py
• Basic library search functionality

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[1.0.0] - 2025-10-01

Initial Release

Core Features:

• 64 fully-documented MCP tools
• JSON Schema validation for all tools
• 8 dynamic resources for project state
• Cross-platform support (Linux, Windows, macOS)
• Comprehensive error handling
• Detailed logging

Tool Categories:

• Project Management (4 tools)
• Board Operations (9 tools)
• Component Management (8 tools)
• Routing (6 tools)
• Export & Manufacturing (5 tools)
• Design Rule Checking (4 tools)
• Schematic Operations (6 tools)
• Symbol Library (3 tools)
• JLCPCB Integration (5 tools)

Platform Support:

• Linux (KiCad 7.x, 8.x, 9.x)
• Windows (KiCad 9.x)
• macOS (KiCad 9.x)

Documentation:

• Complete README with setup instructions
• Platform-specific guides
• Tool reference documentation
• Contributing guidelines

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Version Numbering

• 2.1.0-alpha: Current development version with JLCPCB integration
• 2.0.0-alpha: Router pattern and IPC backend
• 1.0.0: Initial stable release

Breaking Changes

2.1.0-alpha

• None (additive changes only)

2.0.0-alpha

• Tool execution now requires router for 47 tools
• Direct tool access limited to 12 high-frequency tools
• Schema validation stricter (catches errors earlier)

Deprecations

2.1.0-alpha

• docs/JLCPCB_USAGE_GUIDE.md - Superseded by docs/JLCPCB_INTEGRATION.md
• docs/JLCPCB_INTEGRATION_PLAN.md - Implementation complete

Migration Guide

Upgrading to 2.1.0-alpha from 2.0.0-alpha

New Dependencies:

• No new system dependencies
• Python packages: requests (already in requirements.txt)

Database Setup:

1. Run download_jlcpcb_database tool (one-time, ~5-10 minutes)
2. Database created at data/jlcpcb_parts.db
3. Subsequent searches use local database (instant)

API Changes:

• All existing tools remain compatible
• 5 new JLCPCB tools available
• No breaking changes to existing functionality

Upgrading to 2.0.0-alpha from 1.0.0

Router Pattern:

• Some tools now accessed via execute_tool instead of direct calls
• Use list_tool_categories to discover available tools
• Search with search_tools to find specific functionality

IPC Backend (Optional):

• Enable in KiCad: Preferences > Plugins > Enable IPC API Server
• Set KICAD_BACKEND=ipc environment variable
• Falls back to SWIG if unavailable

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Credits

• JLCSearch API: @tscircuit
• JLCParts Database: @yaqwsx
• Local JLCPCB Search: @l3wi
• KiCad: KiCad Development Team
• MCP Protocol: Anthropic

License

See LICENSE file for details.