OpenSWMM MCP + REST Gateway

Two ways to reach the same OpenSWMM 6 engine session pool:

• /mcp -- Model Context Protocol (streamable-HTTP). Point Claude, ChatGPT, Gemini, or LangChain at this URL.
• /docs -- REST API (Swagger UI) for Custom GPT Actions and any other HTTP client. Schema at /openapi.json.

Have a .inp file and a Custom GPT that needs a session_id for it? /upload -- one-click upload, no API knowledge needed. Use this if uploadModelText through the GPT itself fails (the model transcribing a file's exact text into a tool call isn't always reliable) -- this page uploads the real bytes directly, no transcription risk.

/health

Source: openswmm.mcp / openswmm.engine