77.0GB", "available_gb": "27.0GB", "reserved_gb": "24.0GB", "percent_used": "87%", "mount": "/System/Volumes/Data", "summary": "Total: 228.0GB | Used: 177.0GB | Available: 27.0GB | Reserved: 24.0GB | Usage: 87%" } ``` Claude: "Here's your current disk usage information: Total Disk Space: 228.0GB Used Space: 177.0GB Available Space: 27.0GB Reserved Space: 24.0GB Usage Percentage: 87% Mount Point: /System/Volumes/Data Device: /dev/disk3s5 Your disk is currently at 87% capacity, with 27.0GB of space still available. If you're concerned about the high usage, you might want to consider cleaning up some files to free up more space." ## How It Works ### Server Capabilities When the server starts, it advertises its capabilities to Claude through the MCP protocol. Here's what Claude sees: ```python @mcp.tool() def get_disk_usage() -> Dict[str, str]: """Get current disk usage information for the system disk Returns: A dictionary containing disk usage information with fields: - device: Device name - total_gb: Total size in GB - used_gb: Used space in GB - available_gb: Available space in GB - reserved_gb: Space reserved by system in GB - percent_used: Usage percentage - mount: Mount point - summary: Human-readable summary of disk usage """ ``` This tells Claude that: 1. The server provides a tool called `get_disk_usage` 2. The tool returns a dictionary with detailed disk information 3. The docstring explains what each field means ### The Complete Claude-MCP Interaction Flow 1. **Initial System Prompt to Claude**: ``` You are Claude, an AI assistant. You have access to these tools: get_disk_usage() -> Dict[str, str] "Get current disk usage information for the system disk" To use this tool, respond with a XML block: get_disk_usage Explain why you need disk usage information ``` 2. **User Query**: ``` User: What is my current disk usage? ``` 3. **Claude's Tool Selection Response**: ``` I'll check your disk usage information. get_disk_usage User has requested current disk usage information. This tool will provide detailed statistics about disk space utilization. ``` 4. **Claude Desktop App → MCP Server**: ```json // HTTP POST to MCP Server { "jsonrpc": "2.0", "method": "invoke", "params": { "tool": "get_disk_usage", "args": {} }, "id": 1 } ``` 5. **MCP Server → Claude Desktop App**: ```json { "jsonrpc": "2.0", "result": { "device": "/dev/disk3s5", "total_gb": "228.0GB", "used_gb": "177.0GB", "available_gb": "27.0GB", "reserved_gb": "24.0GB", "percent_used": "87%", "mount": "/System/Volumes/Data", "summary": "Total: 228.0GB | Used: 177.0GB | Available: 27.0GB | Reserved: 24.0GB | Usage: 87%" }, "id": 1 } ``` 6. **New Request to Claude** (with tool output as context): ``` User: What is my current disk usage? Tool Response: { "device": "/dev/disk3s5", "total_gb": "228.0GB", "used_gb": "177.0GB", "available_gb": "27.0GB", "reserved_gb": "24.0GB", "percent_used": "87%", "mount": "/System/Volumes/Data", "summary": "Total: 228.0GB | Used: 177.0GB | Available: 27.0GB | Reserved: 24.0GB | Usage: 87%" } Provide a helpful response to the user based on this disk usage information. ``` 7. **Claude's Final Response**: ``` Here's your current disk usage information: Total Disk Space: 228.0GB Used Space: 177.0GB Available Space: 27.0GB Reserved Space: 24.0GB Usage Percentage: 87% Mount Point: /System/Volumes/Data Device: /dev/disk3s5 Your disk is currently at 87% capacity, with 27.0GB of space still available. If you're concerned about the high usage, you might want to consider cleaning up some files to free up more space. ``` This shows the complete flow: 1. Claude starts with knowledge of available

Disk Usage MCP Server (Demo)

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