PubNub MCP Server

Instructions

Implementation Reference

• index.js:530-555 (handler)

  The handler function that executes the 'publish_pubnub_message' tool logic. It uses the PubNub SDK to publish a message to the specified channel and returns the timetoken on success or an error message.

  toolHandlers['publish_pubnub_message'] = async ({ channel, message }) => {
      try {
        const result = await pubnub.publish({
          channel,
          message,
        });
        return {
          content: [
            {
              type: 'text',
              text: `Message published successfully. Timetoken: ${result.timetoken}`,
            },
          ],
        };
      } catch (err) {
        return {
          content: [
            {
              type: 'text',
              text: `Error publishing message: ${err}`,
            },
          ],
          isError: true,
        };
      }
  };

• index.js:558-565 (schema)

  The tool definition including name, description, and Zod schema for input parameters (channel and message).

  toolDefinitions['publish_pubnub_message'] = {
    name: 'publish_pubnub_message',
    description: 'Publishes a message to a specified PubNub channel. Call this tool whenever you need to send data through PubNub. Provide the channel name and message payload. Returns a timetoken confirming successful publication.',
    parameters: {
      channel: z.string().describe('Name of the PubNub channel (string) to publish the message to'),
      message: z.string().describe('Message payload as a string'),
    }
  };

• index.js:1363-1394 (registration)

  The registerAllTools function that registers the 'publish_pubnub_message' tool (along with others) by calling server.tool() with the definition and wrapped handler. Called for main server and HTTP sessions.

  function registerAllTools(serverInstance, chatSdkMode = false) {
    // Tools to exclude when in chat SDK mode
    const chatSdkExcludedTools = [
      'read_pubnub_sdk_docs',
      'write_pubnub_app', 
      'read_pubnub_resources',
      'manage_pubnub_account'
    ];
  
    for (const toolName in toolDefinitions) {
      if (toolHandlers[toolName]) {
        // Skip excluded tools when in chat SDK mode
        if (chatSdkMode && chatSdkExcludedTools.includes(toolName)) {
          continue;
        }
  
        // Special handling for chat SDK docs tool
        if (toolName === 'read_pubnub_chat_sdk_docs' && 
            (chatSdkLanguages.length === 0 || chatSdkTopics.length === 0)) {
          continue; // Skip this tool if chat SDK data isn't loaded
        }
        
        const toolDef = toolDefinitions[toolName];
        serverInstance.tool(
          toolDef.name,
          toolDef.description,
          toolDef.parameters,
          wrapToolHandler(toolHandlers[toolName], toolName)
        );
      }
    }
  }