get-username-casts

Retrieve recent casts from a Farcaster user by specifying their username. Use this tool to fetch and analyze content posted by specific accounts on the Farcaster network.

Instructions

Get casts from a specific Farcaster username

Input Schema

TableJSON Schema

Name	Required	Description	Default
`username`	Yes	Farcaster username
`limit`	No	Maximum number of casts to return (default: 10)

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
      };
    }
  }
);

Farcaster MCP Server