Change tab selection to use 0-based indexing instead of 1-based

Co-authored-by: Skn0tt <14912729+Skn0tt@users.noreply.github.com>

README.md

@@ -662,9 +662,9 @@ X Y coordinate space, based on the provided screenshot.
 
 - **browser_tab_select**
   - Title: Select a tab
-  - Description: Select a tab by index (1-based indexing)
+  - Description: Select a tab by index (0-based indexing)
   - Parameters:
-    - `index` (number): The index of the tab to select (1-based: first tab is 1, second tab is 2, etc.)
+    - `index` (number): The index of the tab to select (0-based: first tab is 0, second tab is 1, etc.)
   - Read-only: **true**
 
 <!-- NOTE: This has been generated via update-readme.js -->
@@ -673,7 +673,7 @@ X Y coordinate space, based on the provided screenshot.
   - Title: Close a tab
   - Description: Close a tab
   - Parameters:
-    - `index` (number, optional): The index of the tab to close (1-based: first tab is 1, second tab is 2, etc.). Closes current tab if not provided.
+    - `index` (number, optional): The index of the tab to close (0-based: first tab is 0, second tab is 1, etc.). Closes current tab if not provided.
   - Read-only: **false**
 
 </details>

src/context.ts

@@ -101,7 +101,7 @@ export class Context {
   }
 
   async selectTab(index: number) {
-    this._currentTab = this._tabs[index - 1];
+    this._currentTab = this._tabs[index];
     await this._currentTab.page.bringToFront();
   }
 
@@ -127,7 +127,7 @@ export class Context {
   }
 
   async closeTab(index: number | undefined) {
-    const tab = index === undefined ? this._currentTab : this._tabs[index - 1];
+    const tab = index === undefined ? this._currentTab : this._tabs[index];
     await tab?.page.close();
     return await this.listTabsMarkdown();
   }

src/tools/tabs.ts

@@ -50,9 +50,9 @@ const selectTab: ToolFactory = captureSnapshot => defineTool({
   schema: {
     name: 'browser_tab_select',
     title: 'Select a tab',
-    description: 'Select a tab by index (1-based indexing)',
+    description: 'Select a tab by index (0-based indexing)',
     inputSchema: z.object({
-      index: z.number().describe('The index of the tab to select (1-based: first tab is 1, second tab is 2, etc.)'),
+      index: z.number().describe('The index of the tab to select (0-based: first tab is 0, second tab is 1, etc.)'),
     }),
     type: 'readOnly',
   },
@@ -108,7 +108,7 @@ const closeTab: ToolFactory = captureSnapshot => defineTool({
     title: 'Close a tab',
     description: 'Close a tab',
     inputSchema: z.object({
-      index: z.number().optional().describe('The index of the tab to close (1-based: first tab is 1, second tab is 2, etc.). Closes current tab if not provided.'),
+      index: z.number().optional().describe('The index of the tab to close (0-based: first tab is 0, second tab is 1, etc.). Closes current tab if not provided.'),
     }),
     type: 'destructive',
   },

tests/tabs.spec.ts

@@ -90,12 +90,12 @@ test('select tab', async ({ client }) => {
   expect(await client.callTool({
     name: 'browser_tab_select',
     arguments: {
-      index: 2,
+      index: 1,
     },
   })).toHaveTextContent(`
 - Ran Playwright code:
 \`\`\`js
-// <internal code to select tab 2>
+// <internal code to select tab 1>
 \`\`\`
 
 ### Open tabs
@@ -118,12 +118,12 @@ test('close tab', async ({ client }) => {
   expect(await client.callTool({
     name: 'browser_tab_close',
     arguments: {
-      index: 3,
+      index: 2,
     },
   })).toHaveTextContent(`
 - Ran Playwright code:
 \`\`\`js
-// <internal code to close tab 3>
+// <internal code to close tab 2>
 \`\`\`
 
 ### Open tabs