MCP Sidecar 🐙⚙️💜

C++ code intelligence for Claude, Cursor, and MCP clients. clangd-powered symbol search, references, call hierarchy, build analysis, and data flow. Zero config, SQLite-backed, single binary.

🎯 What It Does

| Tool | What | |------|------| | symbol_resolve | Find symbols by name (MainWindow, main, Scanner) | | symbol_refs | Find all uses of symbol at file:line:col | | symbol_callers | Who calls this function? (incoming hierarchy) | | symbol_callees | What does this function call? (outgoing hierarchy) | | cpp.build_explain | Full compile command + flags for any file | | cpp.include_explain | Used/required/removable includes | | symbol_card | Symbol dashboard (decls, refs, callers, effects) | | change.impact | What breaks if I change this symbol? |

🚀 Quick Start

# Install
dotnet tool install --global mcp-sidecar

# Pre-index (first time only, 5-15min for large projects)
mcp-sidecar --extract --workspace /path/to/cpp/project

# Use with Claude Desktop, Cursor, etc
mcp-sidecar --workspace /path/to/cpp/project

🧠 Features

Zero config - Finds compile_commands.json automatically
SQLite - No Postgres required, one file per workspace
Resume - Interrupted extractions pick up where they left off
Incremental - Re-indexes only changed files
10GB+ indexes - Handles real C++ codebases (Qt, Boost, C++20)
Progress bar - mcp-sidecar --extract shows live progress

📊 Example

$ mcp-sidecar --extract --workspace ~/LinearScanner-ICS
Extracting: ~/LinearScanner-ICS
Starting clangd... ✓
Starting extraction...

████████████████████████████ 100% | Files: 1742/1742 | Symbols: 35,206 | 12:47
✓ Extraction complete: snapshot_id=1
  Symbols: 35,206
  Files: 1,742
  Time: 12:47

Then in Claude:

> symbol_resolve MainWindow
Found 18 symbols matching 'MainWindow':
  MainWindow (class) @ Applications/Gui/Sources/MainWindow.h:42:8
  MainWindow::MainWindow (constructor) @ Applications/Gui/Sources/MainWindow.cpp:47:5
  ~MainWindow (destructor) @ Applications/Gui/Sources/MainWindow.cpp:57:5

🛠️ Architecture

MCP Client (Claude/Cursor) → MCP Sidecar → clangd (LSP)
                                     ↓
                               SQLite DB (symbols/refs/calls)

clangd - Real-time indexing via LSP
SQLite - Persistent symbol database
MCP - Standard protocol for AI tools

🎪 Why This Exists

Traditional C++ tools (ccls, clangd) are great for editors but terrible for AI. MCP Sidecar bridges the gap:

AI-ready responses - Structured JSON with file:line:col locations
Build-aware - Uses your exact compile_commands.json
Fast queries - Pre-indexed for instant symbol search
No setup - Just point it at a folder with compile_commands.json

🔧 Native Builds (Coming Soon)

# Single binary, no dotnet required
curl -L mcp-sidecar-linux-x64 -o mcp-sidecar
chmod +x mcp-sidecar
./mcp-sidecar --extract --workspace ~/project

📚 MCP Protocol

Full MCP spec: mcp.so

🙏 Thanks

Built with love by Synthia 💜

⭐ Star on GitHub | 🐙 Issues welcome | 💬 Feedback appreciated

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