MCP Reasoner

Instructions

Implementation Reference

• src/index.ts:49-83 (registration)

  Registers the 'mcp-reasoner' tool for ListTools requests, including name, description, and input schema.
  server.setRequestHandler(ListToolsRequestSchema, async () => ({ tools: [{ name: "mcp-reasoner", description: "Advanced reasoning tool with multiple strategies including Beam Search and Monte Carlo Tree Search", inputSchema: { type: "object", properties: { thought: { type: "string", description: "Current reasoning step" }, thoughtNumber: { type: "integer", description: "Current step number", minimum: 1 }, totalThoughts: { type: "integer", description: "Total expected steps", minimum: 1 }, nextThoughtNeeded: { type: "boolean", description: "Whether another step is needed" }, strategyType: { type: "string", enum: Object.values(ReasoningStrategy), description: "Reasoning strategy to use (beam_search or mcts)" } }, required: ["thought", "thoughtNumber", "totalThoughts", "nextThoughtNeeded"] } }] }));
• src/index.ts:86-149 (handler)

  Executes the 'mcp-reasoner' tool: validates input, delegates to Reasoner.processThought, augments response with stats and returns JSON.
  server.setRequestHandler(CallToolRequestSchema, async (request) => { if (request.params.name !== "mcp-reasoner") { return { content: [{ type: "text", text: JSON.stringify({ error: "Unknown tool", success: false }) }], isError: true }; } try { // Process and validate input const step = processInput(request.params.arguments); // Process thought with selected strategy const response = await reasoner.processThought({ thought: step.thought, thoughtNumber: step.thoughtNumber, totalThoughts: step.totalThoughts, nextThoughtNeeded: step.nextThoughtNeeded, strategyType: step.strategyType }); // Get reasoning stats const stats = await reasoner.getStats(); // Return enhanced response const result = { thoughtNumber: step.thoughtNumber, totalThoughts: step.totalThoughts, nextThoughtNeeded: step.nextThoughtNeeded, thought: step.thought, nodeId: response.nodeId, score: response.score, strategyUsed: response.strategyUsed, stats: { totalNodes: stats.totalNodes, averageScore: stats.averageScore, maxDepth: stats.maxDepth, branchingFactor: stats.branchingFactor, strategyMetrics: stats.strategyMetrics } }; return { content: [{ type: "text", text: JSON.stringify(result) }] }; } catch (error) { return { content: [{ type: "text", text: JSON.stringify({ error: error instanceof Error ? error.message : String(error), success: false }) }], isError: true }; } });
• src/index.ts:25-46 (helper)

  Helper function to validate and type-coerce tool input parameters.
  function processInput(input: any) { const result = { thought: String(input.thought || ""), thoughtNumber: Number(input.thoughtNumber || 0), totalThoughts: Number(input.totalThoughts || 0), nextThoughtNeeded: Boolean(input.nextThoughtNeeded), strategyType: input.strategyType as ReasoningStrategy | undefined }; // Validate if (!result.thought) { throw new Error("thought must be provided"); } if (result.thoughtNumber < 1) { throw new Error("thoughtNumber must be >= 1"); } if (result.totalThoughts < 1) { throw new Error("totalThoughts must be >= 1"); } return result; }
• src/reasoner.ts:31-45 (handler)

  Core reasoning handler in Reasoner class: selects strategy and delegates processing, adds strategy info to response.
  public async processThought(request: ReasoningRequest): Promise<ReasoningResponse> { // Switch strategy if requested if (request.strategyType && this.strategies.has(request.strategyType as ReasoningStrategy)) { this.currentStrategy = this.strategies.get(request.strategyType as ReasoningStrategy)!; } // Process thought using current strategy const response = await this.currentStrategy.processThought(request); // Add strategy information to response return { ...response, strategyUsed: this.getCurrentStrategyName() }; }
• src/strategies/factory.ts:11-24 (helper)

  Factory for creating reasoning strategy instances (Beam Search or MCTS) used by the Reasoner.
  export class StrategyFactory { static createStrategy( type: ReasoningStrategy, stateManager: StateManager ): BaseStrategy { switch (type) { case ReasoningStrategy.BEAM_SEARCH: return new BeamSearchStrategy(stateManager); case ReasoningStrategy.MCTS: return new MonteCarloTreeSearchStrategy(stateManager); default: throw new Error(`Unknown strategy type: ${type}`); } }