get-username-casts

Instructions

Implementation Reference

• src/index.ts:602-671 (handler)

  The handler function that executes the get-username-casts tool. It resolves the Farcaster username to a FID, fetches user display name, retrieves recent casts using the Hubble API, formats them, and returns a formatted text response or error.

  async ({ username, limit = 10 }: { username: string; limit?: number }) => {
    try {
      console.error(`Looking up casts for username: ${username}`);
      
      // First, we need to get the FID for the username
      const fid = await getFidByUsername(username);
      
      if (!fid) {
        return {
          content: [
            {
              type: "text",
              text: `User "${username}" not found.`
            }
          ],
          isError: true
        };
      }
      
      console.error(`Found FID ${fid} for username ${username}, fetching user data`);
      
      // Get user data to ensure we have the display name
      const userData = await getUserData(fid);
      
      // Use the display name if available, otherwise use the FID
      const displayName = userData.displayName || `FID: ${fid}`;
      
      console.error(`User data: displayName=${displayName}`);
      
      // Now get the casts for this FID
      const response = await fetchFromHubble(`/castsByFid`, {
        fid,
        pageSize: limit,
        reverse: 1 // Get newest first
      }) as FarcasterCastsResponse;
      
      if (!response.messages || response.messages.length === 0) {
        return {
          content: [
            {
              type: "text",
              text: `No casts found for ${displayName} (FID: ${fid})`
            }
          ]
        };
      }
      
      const castsText = await formatCasts(response.messages, limit);
      
      return {
        content: [
          {
            type: "text",
            text: `# Casts from ${displayName}\n\n${castsText}`
          }
        ]
      };
    } catch (error) {
      console.error("Error in get-username-casts:", error);
      return {
        content: [
          {
            type: "text",
            text: `Error fetching casts by username: ${error instanceof Error ? error.message : String(error)}`
          }
        ],
        isError: true
      };
    }
  }

• src/index.ts:598-601 (schema)

  Zod schema defining the input parameters: required 'username' string and optional 'limit' number.

  {
    username: z.string().describe("Farcaster username"),
    limit: z.number().optional().describe("Maximum number of casts to return (default: 10)")
  },

• src/index.ts:595-672 (registration)

  Registration of the 'get-username-casts' tool on the MCP server using server.tool(), including description, schema, and inline handler function.

  server.tool(
    "get-username-casts",
    "Get casts from a specific Farcaster username",
    {
      username: z.string().describe("Farcaster username"),
      limit: z.number().optional().describe("Maximum number of casts to return (default: 10)")
    },
    async ({ username, limit = 10 }: { username: string; limit?: number }) => {
      try {
        console.error(`Looking up casts for username: ${username}`);
        
        // First, we need to get the FID for the username
        const fid = await getFidByUsername(username);
        
        if (!fid) {
          return {
            content: [
              {
                type: "text",
                text: `User "${username}" not found.`
              }
            ],
            isError: true
          };
        }
        
        console.error(`Found FID ${fid} for username ${username}, fetching user data`);
        
        // Get user data to ensure we have the display name
        const userData = await getUserData(fid);
        
        // Use the display name if available, otherwise use the FID
        const displayName = userData.displayName || `FID: ${fid}`;
        
        console.error(`User data: displayName=${displayName}`);
        
        // Now get the casts for this FID
        const response = await fetchFromHubble(`/castsByFid`, {
          fid,
          pageSize: limit,
          reverse: 1 // Get newest first
        }) as FarcasterCastsResponse;
        
        if (!response.messages || response.messages.length === 0) {
          return {
            content: [
              {
                type: "text",
                text: `No casts found for ${displayName} (FID: ${fid})`
              }
            ]
          };
        }
        
        const castsText = await formatCasts(response.messages, limit);
        
        return {
          content: [
            {
              type: "text",
              text: `# Casts from ${displayName}\n\n${castsText}`
            }
          ]
        };
      } catch (error) {
        console.error("Error in get-username-casts:", error);
        return {
          content: [
            {
              type: "text",
              text: `Error fetching casts by username: ${error instanceof Error ? error.message : String(error)}`
            }
          ],
          isError: true
        };
      }
    }
  );