Chain of Draft (CoD) MCP Server

Instructions

Implementation Reference

• server.py:171-187 (handler)

  Main handler function for the 'get_token_reduction' tool, registered via @app.tool() decorator. Fetches stats from analytics and formats the response string.
  @app.tool() async def get_token_reduction() -> str: """Get token reduction statistics for CoD vs CoT.""" stats = await analytics.get_token_reduction_stats() result = "Token Reduction Analysis:\n\n" if not stats: return "No reduction data available yet." for stat in stats: result += f"Domain: {stat['domain']}\n" result += f"CoD avg tokens: {stat['cod_avg_tokens']:.1f}\n" result += f"CoT avg tokens: {stat['cot_avg_tokens']:.1f}\n" result += f"Reduction: {stat['reduction_percentage']:.1f}%\n\n" return result
• analytics.py:115-150 (helper)

  Database query helper that computes token reduction statistics by averaging tokens used for CoD and CoT approaches per domain.
  async def get_token_reduction_stats(self): """Calculate token reduction statistics for CoD vs CoT.""" session = self.Session() try: domains = session.query(InferenceRecord.domain).distinct().all() results = [] for domain_row in domains: domain = domain_row[0] # Get average tokens for CoD and CoT approaches in this domain cod_avg = session.query(func.avg(InferenceRecord.tokens_used)).filter( InferenceRecord.domain == domain, InferenceRecord.approach == "CoD" ).scalar() or 0 cot_avg = session.query(func.avg(InferenceRecord.tokens_used)).filter( InferenceRecord.domain == domain, InferenceRecord.approach == "CoT" ).scalar() or 0 if cot_avg > 0: reduction_percentage = (1 - (cod_avg / cot_avg)) * 100 else: reduction_percentage = 0 results.append({ "domain": domain, "cod_avg_tokens": cod_avg, "cot_avg_tokens": cot_avg, "reduction_percentage": reduction_percentage }) return results finally: session.close()
• index.js:542-549 (schema)

  Explicit JSON schema definition for the 'get_token_reduction' tool with no input parameters.
  const TOKEN_TOOL = { name: "get_token_reduction", description: "Get token reduction statistics for CoD vs CoT", inputSchema: { type: "object", properties: {} } };
• index.js:715-737 (handler)

  JavaScript handler for 'get_token_reduction' tool in the MCP server request handler, formats stats from analyticsDb.
  if (name === "get_token_reduction") { const stats = analyticsDb.getTokenReductionStats(); let result = "Token Reduction Analysis:\n\n"; if (!stats || stats.length === 0) { result = "No reduction data available yet."; } else { for (const stat of stats) { result += `Domain: ${stat.domain}\n`; result += `CoD avg tokens: ${stat.cod_avg_tokens.toFixed(1)}\n`; result += `CoT avg tokens: ${stat.cot_avg_tokens.toFixed(1)}\n`; result += `Reduction: ${stat.reduction_percentage.toFixed(1)}%\n\n`; } } return { content: [{ type: "text", text: result }] }; }
• index.js:67-106 (helper)

  In-memory analytics helper method that calculates token reduction stats by grouping records by domain and averaging CoD/CoT tokens.
  getTokenReductionStats: function() { // Group by domain const domains = {}; for (const record of this.records) { if (!domains[record.domain]) { domains[record.domain] = { cod_tokens: [], cot_tokens: [] }; } if (record.approach === 'CoD') { domains[record.domain].cod_tokens.push(record.tokens_used); } else if (record.approach === 'CoT') { domains[record.domain].cot_tokens.push(record.tokens_used); } } // Calculate reduction stats return Object.entries(domains).map(([domain, data]) => { const cod_avg = data.cod_tokens.length ? data.cod_tokens.reduce((a, b) => a + b, 0) / data.cod_tokens.length : 0; const cot_avg = data.cot_tokens.length ? data.cot_tokens.reduce((a, b) => a + b, 0) / data.cot_tokens.length : 0; let reduction = 0; if (cot_avg > 0 && cod_avg > 0) { reduction = 100 * (1 - (cod_avg / cot_avg)); } return { domain, cod_avg_tokens: cod_avg, cot_avg_tokens: cot_avg, reduction_percentage: reduction }; }); }