Fear & Greed Index MCP Server

Instructions

Implementation Reference

• src/server.ts:142-171 (handler)

  Handler function that calls fetchFearGreedData and returns the structured Fear & Greed Index data or error.

  async () => {
    try {
      const data = await fetchFearGreedData();
  
      return {
        isError: false,
        content: [
          {
            type: "text",
            text: JSON.stringify(data),
          },
        ],
        structuredContent: {
          data,
        },
      };
    } catch (error) {
      return {
        isError: true,
        content: [
          {
            type: "text",
            text: `Error fetching Fear and Greed Index: ${
              error instanceof Error ? error.message : String(error)
            }`,
          },
        ],
      };
    }
  }

• src/server.ts:132-172 (registration)

  Registration of the 'get_fear_greed_index' tool with description, schemas, and handler.

  server.registerTool(
    "get_fear_greed_index",
    {
      description:
        "Get US stock market Fear & Greed Index data. Returns comprehensive market sentiment analysis including the main composite index and 7 individual indicators (market momentum, stock price strength/breadth, options sentiment, volatility, safe haven demand, junk bond demand). Each indicator includes score (0-100), rating, and timestamp. See schema for detailed field descriptions.",
      inputSchema: {},
      outputSchema: {
        data: fearGreedSchema,
      },
    },
    async () => {
      try {
        const data = await fetchFearGreedData();
  
        return {
          isError: false,
          content: [
            {
              type: "text",
              text: JSON.stringify(data),
            },
          ],
          structuredContent: {
            data,
          },
        };
      } catch (error) {
        return {
          isError: true,
          content: [
            {
              type: "text",
              text: `Error fetching Fear and Greed Index: ${
                error instanceof Error ? error.message : String(error)
              }`,
            },
          ],
        };
      }
    }
  );

• src/server.ts:21-71 (schema)

  Zod schema defining the structure of the Fear & Greed Index data used in outputSchema.

  const fearGreedSchema = z.object({
    fear_and_greed: z
      .object({
        ...itemDataSchema,
        previous_close: z.number().describe("Previous day's closing score"),
        previous_1_week: z.number().describe("Score from 1 week ago"),
        previous_1_month: z.number().describe("Score from 1 month ago"),
        previous_1_year: z.number().describe("Score from 1 year ago"),
      })
      .describe("Main composite Fear & Greed Index with historical comparisons"),
    fear_and_greed_historical: z
      .object(itemDataSchema)
      .describe("Historical Fear & Greed Index data"),
    market_momentum_sp500: z
      .object(itemDataSchema)
      .describe(
        "S&P 500 momentum indicator - measures stock prices vs 125-day moving average"
      ),
    market_momentum_sp125: z
      .object(itemDataSchema)
      .describe("S&P 500 125-day moving average momentum"),
    stock_price_strength: z
      .object(itemDataSchema)
      .describe("Stock price strength - ratio of NYSE 52-week highs vs lows"),
    stock_price_breadth: z
      .object(itemDataSchema)
      .describe("Stock price breadth - McClellan Volume Summation Index"),
    put_call_options: z
      .object(itemDataSchema)
      .describe(
        "Put/Call options ratio - 5-day average (higher ratio indicates fear)"
      ),
    market_volatility_vix: z
      .object(itemDataSchema)
      .describe(
        "Market volatility - VIX fear index (higher values indicate fear)"
      ),
    market_volatility_vix_50: z
      .object(itemDataSchema)
      .describe("VIX 50-day moving average volatility"),
    junk_bond_demand: z
      .object(itemDataSchema)
      .describe(
        "Junk bond demand - yield spread between junk and investment-grade bonds"
      ),
    safe_haven_demand: z
      .object(itemDataSchema)
      .describe(
        "Safe haven demand - difference between 20-day stock and bond returns"
      ),
  });

• src/server.ts:75-124 (helper)

  Helper function that fetches raw data from CNN API, processes it, and validates with fearGreedSchema.

  async function fetchFearGreedData(): Promise<FearGreedData> {
    try {
      const userAgent = new UserAgent();
  
      const response = await fetch(
        "https://production.dataviz.cnn.io/index/fearandgreed/graphdata",
        {
          headers: {
            "User-Agent": userAgent.toString(),
            Accept: "application/json, text/plain, */*",
            "Accept-Language": "en-US,en;q=0.9",
            "Accept-Encoding": "gzip, deflate, br",
            Connection: "keep-alive",
            Referer: "https://www.cnn.com/",
            Origin: "https://www.cnn.com",
            "Cache-Control": "no-cache",
            Pragma: "no-cache",
          },
        }
      );
  
      if (!response.ok) {
        throw new Error(`HTTP error! status: ${response.status}`);
      }
  
      const responseData = await response.json();
      let result = {};
  
      Object.keys(responseData).forEach((k) => {
        const { data, ...rest } = responseData[k];
        result = {
          ...(result || {}),
          [k]: {
            ...rest,
            timestamp:
              typeof rest.timestamp === "number"
                ? new Date(rest.timestamp).toISOString()
                : rest.timestamp,
          },
        };
      });
      return fearGreedSchema.parse(result);
    } catch (error) {
      throw new Error(
        `Failed to fetch Fear and Greed data: ${
          error instanceof Error ? error.message : String(error)
        }`
      );
    }
  }

• src/server.ts:5-19 (schema)

  Base schema for individual Fear & Greed items, extended in fearGreedSchema.

  const itemDataSchema = {
    timestamp: z
      .string()
      .describe("ISO timestamp when the data was last updated"),
    score: z
      .number()
      .describe(
        "Fear & Greed score from 0-100 (0=extreme fear, 100=extreme greed)"
      ),
    rating: z
      .enum(["extreme fear", "fear", "neutral", "greed", "extreme greed"])
      .describe(
        "Textual rating based on the score: 0-25=extreme fear, 26-45=fear, 46-55=neutral, 56-75=greed, 76-100=extreme greed"
      ),
  };