# Handlers Directory
## Purpose
This directory contains request handlers that process MCP protocol messages, manage tool executions, and coordinate with services to fulfill client requests.
## Key Files
- `tool-handlers.ts`: Routes tool calls to their specific implementations
- `resource-handlers.ts`: Lists and retrieves resources
- `prompt-handlers.ts`: Lists and retrieves prompts
- `sampling.ts`: Handles LLM sampling requests
- `notifications.ts`: Manages system notifications
- `callbacks.ts`: Processes responses from sampling operations
- `action-schema.ts`: Defines schemas for actions
## Subdirectories
- `/tools/`: Individual handler implementations for each tool
- `/callbacks/`: Handler implementations for sampling callbacks
## Pattern
Handlers follow a consistent pattern:
1. Validate incoming request data
2. Access the appropriate service
3. Execute the requested operation
4. Format and return the response
5. Handle errors consistently
## Extending for New MCP Servers
When adapting this template for a new MCP server:
1. **Create Tool Handlers**:
- Create handler functions for each of your tools in the `/tools/` directory
- Update the `index.ts` file in the `/tools/` directory to export all handlers
- Ensure handlers validate inputs according to your schemas
2. **Update Resource Handlers**:
- Modify `resource-handlers.ts` to handle your specific resources
- Implement the appropriate data fetching for your API
3. **Customize Sampling**:
- Update `sampling.ts` to use your domain-specific templates
- Implement callback handlers for your sampling operations
4. **Implement Notifications**:
- Update `notifications.ts` to send appropriate notifications for your system
## Example
```typescript
// Example tool handler
export async function handleYourTool(
params: YourToolParams,
context: RequestContext
): Promise<YourToolResult> {
try {
// Validate params if needed
validateYourToolParams(params);
// Access the service
const service = YourService.getInstance();
// Execute the operation
const result = await service.performOperation(params);
// Return formatted result
return {
success: true,
data: result
};
} catch (error) {
// Handle errors
return {
success: false,
error: error instanceof Error ? error.message : String(error)
};
}
}
```
