MCP Browser Tabs Server

Instructions

Implementation Reference

• src/index.ts:355-369 (handler)

  Handler logic for the 'close_tab' tool within the tools/call request handler. Extracts windowIndex and tabIndex from arguments, calls the closeChromeTabByIndex helper function, and returns a success message.

  if (name === "close_tab") {
    const { windowIndex, tabIndex } = request.params.arguments as {
      windowIndex: number;
      tabIndex: number;
    };
    await closeChromeTabByIndex(windowIndex, tabIndex);
    return {
      content: [
        {
          type: "text",
          text: `⚠️ LEGACY: Successfully closed tab at window ${windowIndex}, tab ${tabIndex}. Consider using close_tab_by_id for better reliability.`,
        },
      ],
    };
  }

• src/index.ts:175-198 (helper)

  Helper function that implements the core logic for closing a Chrome tab by window index and tab index using AppleScript executed via osascript.

  async function closeChromeTabByIndex(
    windowIndex: number,
    tabIndex: number
  ): Promise<void> {
    const script = `
      tell application "Google Chrome"
        try
          set targetWindow to window ${windowIndex}
          set targetTab to tab ${tabIndex} of targetWindow
          close targetTab
        on error errMsg
          return "Error: " & errMsg
        end try
      end tell
    `;
  
    try {
      await execAsync(`osascript -e '${script}'`);
    } catch (error) {
      throw new Error(
        `Failed to close Chrome tab: ${error instanceof Error ? error.message : String(error)}`
      );
    }
  }

• src/index.ts:258-267 (registration)

  Registration of the 'close_tab' tool in the list of available tools returned by tools/list, including name, description, and input schema.

  {
    name: "close_tab",
    description: "⚠️ LEGACY DANGER: Close a specific tab using window/tab index. HIGH RISK of closing wrong tabs due to index shifting when tabs are reordered/closed. STRONGLY DEPRECATED: Use close_tab_by_id instead. Only use if Tab ID is unavailable.",
    inputSchema: zodToJsonSchema(
      z.object({
        windowIndex: z.number().int().positive().describe("DANGEROUS: Window index (1-based) - can target wrong window"),
        tabIndex: z.number().int().positive().describe("DANGEROUS: Tab index (1-based) - changes when tabs are reordered"),
      })
    ),
  },

• src/index.ts:261-266 (schema)

  Zod schema definition for the input parameters of the 'close_tab' tool: windowIndex and tabIndex.

  inputSchema: zodToJsonSchema(
    z.object({
      windowIndex: z.number().int().positive().describe("DANGEROUS: Window index (1-based) - can target wrong window"),
      tabIndex: z.number().int().positive().describe("DANGEROUS: Tab index (1-based) - changes when tabs are reordered"),
    })
  ),