join_channel

Instructions

Implementation Reference

• src/talk_to_figma_mcp/tools/document-tools.ts:304-351 (registration)

  Registration of the 'join_channel' tool on the MCP server, defining its schema (channel string) and handler callback.

  // Join Channel Tool
  server.tool(
    "join_channel",
    "Join a specific channel to communicate with Figma",
    {
      channel: z.string().describe("The name of the channel to join"),
    },
    async ({ channel }) => {
      try {
        if (!channel) {
          // If no channel provided, ask the user for input
          return {
            content: [
              {
                type: "text",
                text: "Please provide a channel name to join:",
              },
            ],
            followUp: {
              tool: "join_channel",
              description: "Join the specified channel",
            },
          };
        }
  
        // Use joinChannel instead of sendCommandToFigma to ensure currentChannel is updated
        await joinChannel(channel);
  
        return {
          content: [
            {
              type: "text",
              text: `Successfully joined channel: ${channel}`,
            },
          ],
        };
      } catch (error) {
        return {
          content: [
            {
              type: "text",
              text: `Error joining channel: ${error instanceof Error ? error.message : String(error)}`,
            },
          ],
        };
      }
    }
  );

• src/talk_to_figma_mcp/utils/websocket.ts:197-220 (handler)

  The joinChannel function that sends 'join' command via WebSocket to Figma, updates currentChannel, and verifies with a ping.

  export async function joinChannel(channelName: string): Promise<void> {
    if (!ws || ws.readyState !== WebSocket.OPEN) {
      throw new Error("Not connected to Figma");
    }
  
    try {
      await sendCommandToFigma("join", { channel: channelName });
      currentChannel = channelName;
  
      try {
        await sendCommandToFigma("ping", {}, 12000);
        logger.info(`Joined channel: ${channelName}`);
      } catch (verificationError) {
        currentChannel = null;
        const errorMsg = verificationError instanceof Error
          ? verificationError.message
          : String(verificationError);
        logger.error(`Failed to verify channel ${channelName}: ${errorMsg}`);
        throw new Error(`Failed to verify connection to channel "${channelName}". The Figma plugin may not be connected to this channel.`);
      }
    } catch (error) {
      logger.error(`Failed to join channel: ${error instanceof Error ? error.message : String(error)}`);
      throw error;
    }

• src/talk_to_figma_mcp/tools/document-tools.ts:308-309 (schema)

  Input schema for the join_channel tool: requires a 'channel' string parameter.

  {
    channel: z.string().describe("The name of the channel to join"),

• src/talk_to_figma_mcp/tools/document-tools.ts:3-3 (helper)

  Import of the joinChannel helper function from the websocket utility.

  import { sendCommandToFigma, joinChannel } from "../utils/websocket.js";