When Cursor modifies backend FastAPI routes or SQLAlchemy/Pydantic models in full-stack repositories, backend unit tests frequently pass while frontend React/Next.js client calls silently break at runtime.
I built StackBridge-MCP, an open-source Model Context Protocol server that tracks cross-boundary contracts locally without running heavy test VMs.
Key Capabilities:
• 0.75 ms blast-radius queries powered by SQLite recursive CTEs.
• 99.74% prompt token reduction by returning focused AST contract slices instead of full files.
• Root-cause diagnostic ranking: Identifies primary root causes vs. cascading type breaks and outputs unified Git diff patches.
• Test impact selection: Detects affected test files and flags 0%-coverage blast-radius endpoints.
• Background file watcher: Updates the SQLite graph automatically on file save.
Tested against real-world repos with 56/56 passing tests.
Links & Configuration:
• GitHub: GitHub - ZainUlAbideen02/StackBridge-MCP · GitHub
• PyPI: stackbridge · PyPI
To use it with Cursor, add this to your .cursor/mcp.json:
{
"mcpServers": {
"stackbridge": {
"command": "uvx",
"args": ["stackbridge", "serve"]
}
}
}