doc: add draft README.md

Author: necusjz

tools/aaz-flow/README.md

@@ -0,0 +1,12 @@
+## AAZ MCP Server
+MCP Server for the AAZ API, enabling prune command-line interface, implement custom logic, generate meaningful example, and more.
+
+Please note that AAZ Flow is currently in early development. The functionality and available tools are subject to change and expansion as we continue to develop and improve the server.
+
+### Tools
+1. `generate_code`
+   - xx
+   - Inputs:
+     - xx
+     - xx
+   - Returns: