import { Server } from '@modelcontextprotocol/sdk/server/index.js';
import { CompleteRequestSchema, CompleteResult } from '@modelcontextprotocol/sdk/types.js';
import { CompletionProvider, CompletionRequest } from './types.js';
import { FilePathCompletionProvider } from './providers/FilePathCompletionProvider.js';
import { TagCompletionProvider } from './providers/TagCompletionProvider.js';
/**
* Maximum completion values to return (MCP spec limit: 100)
*/
const MAX_COMPLETION_VALUES = 100;
/**
* Handles MCP completion requests by routing to appropriate providers
*
* Registered providers:
* - FilePathCompletionProvider: vault://note/{path}, vault://folder/{path}
* - TagCompletionProvider: vault://tag/{tagname}
*/
export class CompletionHandler {
private providers: CompletionProvider[];
constructor() {
// Register completion providers
this.providers = [
new FilePathCompletionProvider(),
new TagCompletionProvider(),
];
}
/**
* Register completion handler with MCP server
*/
register(server: Server): void {
server.setRequestHandler(CompleteRequestSchema, async (request) => {
return this.handleComplete(request.params as CompletionRequest);
});
// Register completion capability
// Note: This might already be registered by resources/prompts
// The SDK handles duplicate capability registration gracefully
try {
server.registerCapabilities({
completions: {},
});
} catch (error) {
// Capability already registered - this is fine
}
}
/**
* Handle completion request
*/
private async handleComplete(request: CompletionRequest): Promise<CompleteResult> {
try {
// Find provider that can handle this request
const provider = this.providers.find(p =>
p.canComplete(request.ref, request.argument)
);
if (!provider) {
// No provider found - return empty completions
return {
completion: {
values: [],
total: 0,
hasMore: false,
},
};
}
// Get completions from provider
const values = await provider.getCompletions(request.ref, request.argument);
// Ensure we don't exceed MCP limit
const limitedValues = values.slice(0, MAX_COMPLETION_VALUES);
return {
completion: {
values: limitedValues,
total: values.length,
hasMore: values.length > MAX_COMPLETION_VALUES,
},
};
} catch (error) {
console.error('Completion error:', error);
// Return empty completions on error
return {
completion: {
values: [],
total: 0,
hasMore: false,
},
};
}
}
}
