Chain of Draft (CoD) MCP Server

Instructions

Implementation Reference

• index.js:662-681 (handler)

  Handler for the 'logic_solve' tool in the MCP callTool request handler. Invokes the core Chain of Draft reasoning client with domain set to 'logic' and formats the response.
  if (name === "logic_solve") { const result = await chainOfDraftClient.solveWithReasoning({ ...args, domain: "logic" }); const formattedResponse = `Chain of ${result.approach} reasoning (${result.word_limit} word limit):\n\n` + `${result.reasoning_steps}\n\n` + `Final answer: ${result.final_answer}\n\n` + `Stats: ${result.token_count} tokens, ${result.execution_time_ms.toFixed(0)}ms, ` + `complexity score: ${result.complexity}`; return { content: [{ type: "text", text: formattedResponse }] }; }
• index.js:505-526 (schema)

  Input schema definition for the logic_solve tool, used in tool listing.
  const LOGIC_TOOL = { name: "logic_solve", description: "Solve a logic problem using Chain of Draft reasoning", inputSchema: { type: "object", properties: { problem: { type: "string", description: "The logic problem to solve" }, approach: { type: "string", description: "Force 'CoD' or 'CoT' approach" }, max_words_per_step: { type: "number", description: "Maximum words per reasoning step" } }, required: ["problem"] } };
• server.py:122-140 (handler)

  Handler function for logic_solve tool in FastMCP server. Registered via @app.tool() decorator (which infers schema from parameters). Delegates to chain_of_draft_solve with domain='logic'.
  @app.tool() async def logic_solve( problem: str, approach: str = None, max_words_per_step: int = None ) -> str: """Solve a logic problem using Chain of Draft reasoning. Args: problem: The logic problem to solve approach: Force "CoD" or "CoT" approach (default: auto-select) max_words_per_step: Maximum words per step (default: adaptive) """ return await chain_of_draft_solve( problem=problem, domain="logic", approach=approach, max_words_per_step=max_words_per_step )
• index.js:309-420 (helper)

  Core ChainOfDraftClient.solveWithReasoning helper implementing the reasoning logic (complexity estimation, approach selection CoD/CoT, prompt creation, Anthropic Claude API call, response extraction, format enforcement, analytics logging). Used by all domain tools including logic_solve.
  async solveWithReasoning(params) { const { problem, domain = 'general', max_words_per_step = null, approach = null, enforce_format = true, adaptive_word_limit = true } = params; const startTime = Date.now(); // Analyze problem complexity const analysis = complexityEstimator.analyzeProblem(problem, domain); const complexity = analysis.estimated_complexity; // Determine word limit let wordLimit = max_words_per_step; if (!wordLimit && adaptive_word_limit) { wordLimit = complexity; } else if (!wordLimit) { // Default based on domain wordLimit = complexityEstimator.domainBaseLimits[domain] || 5; } // Determine approach (CoD or CoT) const performanceStats = analyticsDb.getPerformanceByDomain(domain); const selectedApproach = approach || reasoningSelector.selectApproach(domain, complexity, performanceStats); // Create prompt based on approach const prompt = selectedApproach === 'CoD' ? createCodPrompt(problem, domain, [], wordLimit) : createCotPrompt(problem, domain, []); // Call Claude const response = await anthropic.messages.create({ model: 'claude-3-sonnet-20240229', max_tokens: 1000, messages: [ { role: 'user', content: prompt } ] }); // Extract reasoning and answer const fullText = response.content[0].text; // Extract final answer (assuming it comes after the reasoning, often starts with "Answer:" or similar) let reasoningSteps = fullText; let finalAnswer = ''; // Common patterns for final answer sections const answerPatterns = [ /(?:Final Answer|Answer|Therefore):?\s*(.*?)$/is, /(?:In conclusion|To conclude|Thus|Hence|So),\s*(.*?)$/is, /(?:The answer is|The result is|The solution is)\s*(.*?)$/is ]; // Try to extract the final answer with each pattern for (const pattern of answerPatterns) { const match = fullText.match(pattern); if (match && match[1]) { finalAnswer = match[1].trim(); reasoningSteps = fullText.substring(0, fullText.indexOf(match[0])).trim(); break; } } // If no pattern matched, just use the last sentence if (!finalAnswer) { const sentences = fullText.split(/[.!?]+\s+/); if (sentences.length > 1) { finalAnswer = sentences.pop().trim(); reasoningSteps = sentences.join('. ') + '.'; } } // Apply format enforcement if needed if (enforce_format && selectedApproach === 'CoD') { reasoningSteps = formatEnforcer.enforceWordLimit(reasoningSteps, wordLimit); } // Calculate execution time const executionTime = Date.now() - startTime; // Estimate token count (rough approximation) const tokenCount = Math.ceil(fullText.length / 4); // Record analytics analyticsDb.addRecord({ problem_id: problem.substring(0, 20), problem_text: problem, domain, approach: selectedApproach, word_limit: wordLimit, tokens_used: tokenCount, execution_time_ms: executionTime, reasoning_steps: reasoningSteps, answer: finalAnswer }); // Return result return { approach: selectedApproach, reasoning_steps: reasoningSteps, final_answer: finalAnswer, token_count: tokenCount, word_limit: wordLimit, complexity: complexity, execution_time_ms: executionTime }; }