| """M3D module SDK. |
| |
| A module = a module.json manifest + an MCP server exposing the same tools |
| in-process (used by the DAG runner) and over stdio/HTTP (used by external |
| agents and agentic harnesses). One class, one interface, every runtime. |
| |
| Built on MCP Python SDK v2 (pip install mcp==2.2.0): |
| from mcp.server import MCPServer; @mcp.tool() registers a typed tool. |
| """ |
| from __future__ import annotations |
|
|
| import json |
| from typing import Any |
|
|
| from mcp.server import MCPServer |
|
|
|
|
| class M3DModule: |
| def __init__(self, manifest: dict): |
| assert "id" in manifest and "version" in manifest, "manifest needs id + version" |
| assert "license" in manifest, "every M3D module declares its license graph" |
| self.manifest = manifest |
| self.server = MCPServer(manifest["id"]) |
| self._tools: dict[str, Any] = {} |
|
|
| def tool(self, name: str | None = None): |
| """Register a typed function as both an M3D tool and an MCP tool.""" |
| def deco(fn): |
| tool_name = name or fn.__name__ |
| self._tools[tool_name] = fn |
| self.server.add_tool(fn, name=tool_name) |
| return fn |
| return deco |
|
|
| def run_tool(self, name: str, args: dict) -> Any: |
| """Direct in-process call used by the DAG runner (isolation principle).""" |
| if name not in self._tools: |
| raise KeyError( |
| f"module {self.manifest['id']} has no tool {name!r}; " |
| f"available: {sorted(self._tools)}" |
| ) |
| return self._tools[name](**args) |
|
|
| def serve(self, transport: str = "stdio") -> None: |
| """Serve over MCP — stdio/sse/streamable-http, any agentic harness can attach.""" |
| self.server.run(transport=transport) |
|
|
| def manifest_json(self) -> str: |
| return json.dumps(self.manifest, indent=2) |
