MCP Browser Tabs Server

Instructions

Implementation Reference

• src/index.ts:140-172 (handler)

  Core handler function that executes the activation of a Chrome tab by its unique ID using AppleScript executed via osascript.

  async function activateChromeTabById(tabId: number): Promise<void> {
    const script = `
      tell application "Google Chrome"
        set targetTabID to "${tabId}"
        set tabFound to false
        
        repeat with w in (every window)
          repeat with i from 1 to count of (every tab of w)
            set t to item i of (every tab of w)
            if (id of t) as string = targetTabID then
              set (active tab index of w) to i
              set index of w to 1
              set tabFound to true
              exit repeat
            end if
          end repeat
          if tabFound then exit repeat
        end repeat
        
        if not tabFound then
          error "Tab with ID " & targetTabID & " not found"
        end if
      end tell
    `;
  
    try {
      await execAsync(`osascript -e '${script}'`);
    } catch (error) {
      throw new Error(
        `Failed to activate Chrome tab with ID ${tabId}: ${error instanceof Error ? error.message : String(error)}`
      );
    }
  }

• src/index.ts:342-353 (handler)

  MCP tool dispatch handler block that parses arguments, calls the core activateChromeTabById function, and returns success response.

  if (name === "activate_tab_by_id") {
    const { tabId } = request.params.arguments as { tabId: number };
    await activateChromeTabById(tabId);
    return {
      content: [
        {
          type: "text", 
          text: `✅ Successfully activated tab with ID ${tabId}`,
        },
      ],
    };
  }

• src/index.ts:253-256 (schema)

  Zod schema defining the input parameter 'tabId' for the activate_tab_by_id tool.

    z.object({
      tabId: z.number().int().positive().describe("The exact Tab ID number from [Tab ID: xxxxx] in get_tabs output - NOT the display number"),
    })
  ),

• src/index.ts:249-257 (registration)

  Tool registration in the list of tools returned by tools/list, including name, description, and schema.

  {
    name: "activate_tab_by_id", 
    description: "🔥 PREFERRED METHOD: Activate (focus) a specific tab in Google Chrome using its unique tab ID. Brings the tab to the front and makes it active. Extract the Tab ID from [Tab ID: 1234567890] in get_tabs output.",
    inputSchema: zodToJsonSchema(
      z.object({
        tabId: z.number().int().positive().describe("The exact Tab ID number from [Tab ID: xxxxx] in get_tabs output - NOT the display number"),
      })
    ),
  },