base-price-oracle-mcp

Instructions

Implementation Reference

• src/index.ts:579-615 (handler)

  The handler for the get_volatility MCP tool, which calculates price volatility based on swap history.

  async ({ token_address, lookback_hours }) => {
    try {
      const quoteAddress = WETH;
      const [tokenDecimals, quoteDecimals, tokenSymbol] = await Promise.all([
        getTokenDecimals(token_address),
        getTokenDecimals(quoteAddress),
        getTokenSymbol(token_address),
      ]);
  
      const pools = await findAllPools(token_address, quoteAddress);
      if (pools.length === 0) {
        return { content: [{ type: "text" as const, text: `No DEX pools found for ${token_address} on Base.` }] };
      }
  
      const bestPool = pools[0];
      // Base: ~2s blocks, so lookback_hours * 3600 / 2
      const lookbackBlocks = Math.min(Math.floor((lookback_hours * 3600) / 2), 50000);
      const swaps = await getSwapHistory(bestPool, tokenDecimals, quoteDecimals, lookbackBlocks);
  
      if (swaps.length < 3) {
        return {
          content: [{
            type: "text" as const,
            text: JSON.stringify({
              token: token_address,
              symbol: tokenSymbol,
              message: `Insufficient swap data (${swaps.length} swaps). Need at least 3 for volatility calculation.`,
            }, null, 2),
          }],
        };
      }
  
      const prices = swaps.map((s) => s.price);
      const returns = calculateReturns(prices);
      const vol = stddev(returns);
      const annualized = vol * Math.sqrt(365 * 24); // hourly returns annualized

• src/index.ts:572-578 (registration)

  The registration of the get_volatility tool within the MCP server.

  server.tool(
    "get_volatility",
    "Calculate price volatility (standard deviation of returns) from recent swaps",
    {
      token_address: z.string().describe("Token contract address on Base"),
      lookback_hours: z.number().default(24).describe("Hours to look back for swap data"),
    },