docs: update README with Python version requirements

- Add Requirements section with Python 3.9+ for core SDK
- Add installation options for optional features
- Document MCP server requiring Python 3.10+
- Add note about CrewAI requiring Python 3.10+

Author: ryoppippi

README.md

@@ -18,12 +18,32 @@ StackOne AI provides a unified interface for accessing various SaaS tools throug
   - CrewAI Tools
   - LangGraph Tool Node
 
+## Requirements
+
+- Python 3.9+ (core SDK functionality)
+- Python 3.10+ (for MCP server and CrewAI examples)
+
 ## Installation
 
+### Basic Installation
+
 ```bash
 pip install stackone-ai
 ```
 
+### Optional Features
+
+```bash
+# Install with MCP server support (requires Python 3.10+)
+pip install stackone-ai[server]
+
+# Install with CrewAI examples (requires Python 3.10+)
+pip install stackone-ai[examples]
+
+# Install everything
+pip install stackone-ai[server,examples]
+```
+
 ## Quick Start
 
 ```python
@@ -82,10 +102,12 @@ for tool_call in response.tool_calls:
 </details>
 
 <details>
-<summary>CrewAI Integration</summary>
+<summary>CrewAI Integration (Python 3.10+)</summary>
 
 CrewAI uses LangChain tools natively, making integration seamless:
 
+> **Note**: CrewAI requires Python 3.10+. Install with `pip install stackone-ai[examples]`
+
 ```python
 from crewai import Agent, Crew, Task
 from stackone_ai import StackOneToolSet