feat: Introduce reactive mcpStore for client lifecycle management
This commit is contained in:
Aleksander Grygier
parent
9ab2326e79
commit
5f5d5ab45f
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@ -0,0 +1,264 @@
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import { browser } from '$app/environment';
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import { MCPClient, type IMCPClient } from '$lib/mcp';
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import { buildMcpClientConfig } from '$lib/config/mcp';
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import { config } from '$lib/stores/settings.svelte';
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/**
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* mcpStore - Reactive store for MCP (Model Context Protocol) client management
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*
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* This store manages:
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* - MCP client lifecycle (initialization, shutdown)
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* - Connection state tracking
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* - Available tools from connected MCP servers
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* - Error handling for MCP operations
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*
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* **Architecture & Relationships:**
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* - **MCPClient**: SDK-based client wrapper for MCP server communication
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* - **mcpStore** (this class): Reactive store for MCP state
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* - **ChatService**: Uses mcpStore for agentic orchestration
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* - **settingsStore**: Provides MCP server configuration
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*
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* **Key Features:**
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* - Reactive state with Svelte 5 runes ($state, $derived)
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* - Automatic reinitialization on config changes
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* - Graceful error handling with fallback to standard chat
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*/
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class MCPStore {
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// ─────────────────────────────────────────────────────────────────────────────
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// State
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// ─────────────────────────────────────────────────────────────────────────────
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private _client = $state<MCPClient | null>(null);
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private _isInitializing = $state(false);
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private _error = $state<string | null>(null);
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private _configSignature = $state<string | null>(null);
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private _initPromise: Promise<MCPClient | undefined> | null = null;
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// ─────────────────────────────────────────────────────────────────────────────
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// Computed Getters
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// ─────────────────────────────────────────────────────────────────────────────
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get client(): IMCPClient | null {
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return this._client;
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}
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get isInitializing(): boolean {
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return this._isInitializing;
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}
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get isInitialized(): boolean {
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return this._client !== null;
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}
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get error(): string | null {
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return this._error;
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}
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/**
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* Check if MCP is enabled (has configured servers)
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*/
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get isEnabled(): boolean {
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const mcpConfig = buildMcpClientConfig(config());
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return (
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mcpConfig !== null && mcpConfig !== undefined && Object.keys(mcpConfig.servers).length > 0
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);
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}
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/**
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* Get list of available tool names
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*/
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get availableTools(): string[] {
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return this._client?.listTools() ?? [];
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}
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/**
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* Get tool definitions for LLM
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*/
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async getToolDefinitions(): Promise<
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{
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type: 'function';
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function: { name: string; description?: string; parameters: Record<string, unknown> };
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}[]
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> {
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if (!this._client) return [];
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return this._client.getToolsDefinition();
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}
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// ─────────────────────────────────────────────────────────────────────────────
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// Lifecycle
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// ─────────────────────────────────────────────────────────────────────────────
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/**
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* Ensure MCP client is initialized with current config.
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* Returns the client if successful, undefined otherwise.
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* Handles config changes by reinitializing as needed.
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*/
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async ensureClient(): Promise<IMCPClient | undefined> {
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if (!browser) return undefined;
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const mcpConfig = buildMcpClientConfig(config());
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const signature = mcpConfig ? JSON.stringify(mcpConfig) : null;
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// No config - shutdown if needed
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if (!signature) {
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await this.shutdown();
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return undefined;
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}
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// Already initialized with correct config
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if (this._client && this._configSignature === signature) {
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return this._client;
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}
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// Init in progress with correct config - wait for it
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if (this._initPromise && this._configSignature === signature) {
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return this._initPromise;
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}
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// Config changed or first init - shutdown old client first
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if (this._client || this._initPromise) {
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await this.shutdown();
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}
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// Initialize new client
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return this.initialize(signature, mcpConfig!);
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}
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/**
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* Initialize MCP client with given config
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*/
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private async initialize(
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signature: string,
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mcpConfig: ReturnType<typeof buildMcpClientConfig>
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): Promise<MCPClient | undefined> {
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if (!mcpConfig) return undefined;
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this._isInitializing = true;
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this._error = null;
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this._configSignature = signature;
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const client = new MCPClient(mcpConfig);
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this._initPromise = client
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.initialize()
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.then(() => {
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// Check if config changed during initialization
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if (this._configSignature !== signature) {
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void client.shutdown().catch((err) => {
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console.error('[MCP Store] Failed to shutdown stale client:', err);
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});
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return undefined;
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}
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this._client = client;
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this._isInitializing = false;
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console.log(
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`[MCP Store] Initialized with ${client.listTools().length} tools:`,
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client.listTools()
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);
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return client;
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})
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.catch((error) => {
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console.error('[MCP Store] Initialization failed:', error);
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this._error = error instanceof Error ? error.message : String(error);
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this._isInitializing = false;
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void client.shutdown().catch((err) => {
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console.error('[MCP Store] Failed to shutdown after error:', err);
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});
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return undefined;
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})
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.finally(() => {
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if (this._configSignature === signature) {
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this._initPromise = null;
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}
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});
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return this._initPromise;
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}
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/**
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* Shutdown MCP client and clear state
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*/
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async shutdown(): Promise<void> {
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// Wait for any pending initialization
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if (this._initPromise) {
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await this._initPromise.catch(() => {});
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this._initPromise = null;
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}
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if (this._client) {
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const clientToShutdown = this._client;
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this._client = null;
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this._configSignature = null;
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this._error = null;
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try {
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await clientToShutdown.shutdown();
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console.log('[MCP Store] Client shutdown complete');
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} catch (error) {
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console.error('[MCP Store] Shutdown error:', error);
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}
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}
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}
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// ─────────────────────────────────────────────────────────────────────────────
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// Tool Execution
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// ─────────────────────────────────────────────────────────────────────────────
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/**
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* Execute a tool call via MCP client
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*/
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async execute(
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toolCall: { id: string; function: { name: string; arguments: string } },
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abortSignal?: AbortSignal
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): Promise<string> {
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if (!this._client) {
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throw new Error('MCP client not initialized');
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}
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return this._client.execute(toolCall, abortSignal);
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}
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// ─────────────────────────────────────────────────────────────────────────────
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// Utilities
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// ─────────────────────────────────────────────────────────────────────────────
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/**
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* Clear error state
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*/
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clearError(): void {
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this._error = null;
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}
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}
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// ─────────────────────────────────────────────────────────────────────────────
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// Singleton Instance & Exports
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// ─────────────────────────────────────────────────────────────────────────────
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export const mcpStore = new MCPStore();
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// Reactive exports for components
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export function mcpClient() {
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return mcpStore.client;
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}
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export function mcpIsInitializing() {
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return mcpStore.isInitializing;
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}
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export function mcpIsInitialized() {
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return mcpStore.isInitialized;
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}
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export function mcpError() {
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return mcpStore.error;
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}
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export function mcpIsEnabled() {
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return mcpStore.isEnabled;
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}
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export function mcpAvailableTools() {
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return mcpStore.availableTools;
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}
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