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MCP Builder

The MCP builder is the final synthesis step. It takes parsed imports, helpers, tool functions, and conflict metadata and writes a unified MCP server.

Output​

mcp_unified_server.py

Responsibilities​

  • write the MCP header and runtime footer
  • include safe imports
  • include utility functions, classes, and globals
  • include extracted @tool functions
  • emit comment blocks for env requirements, skipped repos, and build conflicts

Generated runtime shape​

The builder creates a FastMCP server using streamable-http transport. The --host and --port values passed at build time are baked into the output file:

if __name__ == "__main__":
    mcp.run(transport='streamable-http', host='0.0.0.0', port=8000)

To use a different port, pass --port at build time:

toolstorepy build --queries queries.json --index core-tools --port 9090

This generates:

if __name__ == "__main__":
    mcp.run(transport='streamable-http', host='0.0.0.0', port=9090)

Conflict handling​

The builder surfaces parser decisions such as:

  • duplicate tool renames
  • helper collisions
  • dropped relative imports
  • repos that contributed no tools
  • tools that may fail because required helper symbols were removed

This makes the generated server auditable instead of silently rewriting code behind the scenes.