Tool List Changed Plugin

This plugin demonstrates dynamic tool list management in hyper-mcp. It showcases how a plugin can modify its tool list at runtime and notify the MCP server about these changes.

Features

• Dynamic Tool Creation: Starts with a single add_tool and dynamically creates new tools
• Host Function Integration: Uses the notify_tool_list_changed host function to notify the server
• Atomic Counter: Thread-safe tool counting using atomic operations

How It Works

The plugin begins with only one callable tool:

• add_tool: When called, this tool creates a new tool named tool_n (where n starts at 1 and increments)

After each call to add_tool:

1. A new tool tool_n is added to the plugin's tool list
2. The plugin calls notify_tool_list_changed() to inform the MCP server
3. The server updates its understanding of available tools

Tools

Initial Tool

• add_tool: Creates a new dynamic tool and notifies the server of the tool list change
  • Takes no parameters
  • Returns a JSON object with the new tool name and current tool count

Dynamic Tools

• tool_1, tool_2, tool_3, ...: Created dynamically when add_tool is called
  • Each tool returns information about itself when called
  • Takes no parameters

Usage Example

1. Initial state: Only add_tool is available
2. Call add_tool: Creates tool_1 and notifies the server
3. Call add_tool again: Creates tool_2 and notifies the server
4. Call tool_1: Returns information about being the first dynamically created tool

Building

cd hyper-mcp/examples/plugins/v1/tool-list-changed
cargo build --target wasm32-unknown-unknown --release

The compiled WASM file will be available at: target/wasm32-unknown-unknown/release/tool_list_changed.wasm

Configuration

This plugin requires no additional configuration. It uses atomic operations to maintain thread-safe state across calls.

Implementation Details

• Uses AtomicUsize for thread-safe tool counting
• Calls the notify_tool_list_changed host function after each tool addition
• Implements both static (add_tool) and dynamic (tool_n) tool handling
• Provides JSON responses with relevant information about operations