feat(chromium): expose tab strip metadata via page.tabInfo() by yury-s · Pull Request #42355 · microsoft/playwright

Yury Semikhatsky (yury-s) · 2026-08-21T18:37:33Z

Summary

New Chromium-only page.tabInfo() returns the real tab strip state (active, index, pinned, groupId, windowId) from Target.embedderData (Chrome 150+). Returns null on other browsers, older Chromium and the headless shell.
Concurrent calls coalesce into a single browser-wide CDP query.
The browser_tabs MCP tool marks the tab that is actually visible to the user.

Returns the real browser tab state (active, index, pinned, groupId, windowId) for a page, using Target.embedderData available in Chrome 150+. Returns null on other browsers, older Chromium and the headless shell. Concurrent calls share a single browser-wide query. The browser_tabs MCP tool now marks the tab that is actually visible to the user. Fixes: microsoft#41873

github-actions · 2026-08-21T23:50:23Z

Test results for "tests 1"

3 flaky

⚠️ [chromium-library] › library/video.spec.ts:736 › screencast › should work with video+trace `@chromium-ubuntu-22.04-arm-node20`
⚠️ [chromium-library] › library/tracing.spec.ts:494 › should produce screencast frames fit `@chromium-ubuntu-22.04-node24`
⚠️ [playwright-test] › ui-mode-trace.spec.ts:827 › should update state on subsequent run `@windows-latest-node22`

51359 passed, 1238 skipped

Merge workflow run.

github-actions · 2026-08-21T23:51:47Z

Test results for "MCP"

66 failed
❌ [chrome] › mcp/cli-devtools.spec.ts:217 › video-start-stop @mcp-macos-latest-chrome
❌ [chrome] › mcp/cli-json.spec.ts:123 › tab-new creates a new tab and returns tab list @mcp-macos-latest-chrome
❌ [chrome] › mcp/cli-json.spec.ts:133 › tab-list lists all tabs @mcp-macos-latest-chrome
❌ [chrome] › mcp/cli-json.spec.ts:144 › tab-close closes a tab and returns remaining tabs @mcp-macos-latest-chrome
❌ [chrome] › mcp/screenshot.spec.ts:405 › browser_take_screenshot (viewport without snapshot) @mcp-macos-latest-chrome
❌ [chrome] › mcp/cli-devtools.spec.ts:217 › video-start-stop @mcp-ubuntu-latest-chrome
❌ [chrome] › mcp/cli-json.spec.ts:123 › tab-new creates a new tab and returns tab list @mcp-ubuntu-latest-chrome
❌ [chrome] › mcp/cli-json.spec.ts:133 › tab-list lists all tabs @mcp-ubuntu-latest-chrome
❌ [chrome] › mcp/cli-json.spec.ts:144 › tab-close closes a tab and returns remaining tabs @mcp-ubuntu-latest-chrome
❌ [chrome] › mcp/screenshot.spec.ts:405 › browser_take_screenshot (viewport without snapshot) @mcp-ubuntu-latest-chrome
❌ [chrome] › mcp/cli-devtools.spec.ts:217 › video-start-stop @mcp-windows-latest-chrome
❌ [chrome] › mcp/cli-json.spec.ts:123 › tab-new creates a new tab and returns tab list @mcp-windows-latest-chrome
❌ [chrome] › mcp/cli-json.spec.ts:133 › tab-list lists all tabs @mcp-windows-latest-chrome
❌ [chrome] › mcp/cli-json.spec.ts:144 › tab-close closes a tab and returns remaining tabs @mcp-windows-latest-chrome
❌ [chrome] › mcp/screenshot.spec.ts:405 › browser_take_screenshot (viewport without snapshot) @mcp-windows-latest-chrome
❌ [chromium] › mcp/cli-devtools.spec.ts:217 › video-start-stop @mcp-macos-latest-chromium
❌ [chromium] › mcp/cli-json.spec.ts:123 › tab-new creates a new tab and returns tab list @mcp-macos-latest-chromium
❌ [chromium] › mcp/cli-json.spec.ts:133 › tab-list lists all tabs @mcp-macos-latest-chromium
❌ [chromium] › mcp/cli-json.spec.ts:144 › tab-close closes a tab and returns remaining tabs @mcp-macos-latest-chromium
❌ [chromium] › mcp/screenshot.spec.ts:405 › browser_take_screenshot (viewport without snapshot) @mcp-macos-latest-chromium
❌ [chromium] › mcp/cli-devtools.spec.ts:217 › video-start-stop @mcp-windows-latest-chromium
❌ [chromium] › mcp/cli-json.spec.ts:123 › tab-new creates a new tab and returns tab list @mcp-windows-latest-chromium
❌ [chromium] › mcp/cli-json.spec.ts:133 › tab-list lists all tabs @mcp-windows-latest-chromium
❌ [chromium] › mcp/cli-json.spec.ts:144 › tab-close closes a tab and returns remaining tabs @mcp-windows-latest-chromium
❌ [chromium] › mcp/screenshot.spec.ts:405 › browser_take_screenshot (viewport without snapshot) @mcp-windows-latest-chromium
❌ [chromium] › mcp/cli-devtools.spec.ts:217 › video-start-stop @mcp-ubuntu-latest-chromium
❌ [chromium] › mcp/cli-json.spec.ts:123 › tab-new creates a new tab and returns tab list @mcp-ubuntu-latest-chromium
❌ [chromium] › mcp/cli-json.spec.ts:133 › tab-list lists all tabs @mcp-ubuntu-latest-chromium
❌ [chromium] › mcp/cli-json.spec.ts:144 › tab-close closes a tab and returns remaining tabs @mcp-ubuntu-latest-chromium
❌ [chromium] › mcp/screenshot.spec.ts:405 › browser_take_screenshot (viewport without snapshot) @mcp-ubuntu-latest-chromium
❌ [firefox] › mcp/tabs.spec.ts:36 › list initial tabs @mcp-ubuntu-latest-firefox
❌ [firefox] › mcp/tabs.spec.ts:47 › list first tab @mcp-ubuntu-latest-firefox
❌ [firefox] › mcp/tabs.spec.ts:81 › create new tab with url @mcp-ubuntu-latest-firefox
❌ [firefox] › mcp/tabs.spec.ts:94 › select tab @mcp-ubuntu-latest-firefox
❌ [firefox] › mcp/tabs.spec.ts:123 › close tab @mcp-ubuntu-latest-firefox
❌ [firefox] › mcp/cli-mouse.spec.ts:38 › mousewheel @mcp-windows-latest-firefox
❌ [firefox] › mcp/tabs.spec.ts:36 › list initial tabs @mcp-windows-latest-firefox
❌ [firefox] › mcp/tabs.spec.ts:47 › list first tab @mcp-windows-latest-firefox
❌ [firefox] › mcp/tabs.spec.ts:81 › create new tab with url @mcp-windows-latest-firefox
❌ [firefox] › mcp/tabs.spec.ts:94 › select tab @mcp-windows-latest-firefox
❌ [firefox] › mcp/tabs.spec.ts:123 › close tab @mcp-windows-latest-firefox
❌ [firefox] › mcp/tabs.spec.ts:36 › list initial tabs @mcp-macos-latest-firefox
❌ [firefox] › mcp/tabs.spec.ts:47 › list first tab @mcp-macos-latest-firefox
❌ [firefox] › mcp/tabs.spec.ts:81 › create new tab with url @mcp-macos-latest-firefox
❌ [firefox] › mcp/tabs.spec.ts:94 › select tab @mcp-macos-latest-firefox
❌ [firefox] › mcp/tabs.spec.ts:123 › close tab @mcp-macos-latest-firefox
❌ [msedge] › mcp/cli-devtools.spec.ts:217 › video-start-stop @mcp-windows-latest-msedge
❌ [msedge] › mcp/cli-json.spec.ts:123 › tab-new creates a new tab and returns tab list @mcp-windows-latest-msedge
❌ [msedge] › mcp/cli-json.spec.ts:133 › tab-list lists all tabs @mcp-windows-latest-msedge
❌ [msedge] › mcp/cli-json.spec.ts:144 › tab-close closes a tab and returns remaining tabs @mcp-windows-latest-msedge
❌ [msedge] › mcp/screenshot.spec.ts:405 › browser_take_screenshot (viewport without snapshot) @mcp-windows-latest-msedge
❌ [webkit] › mcp/tabs.spec.ts:36 › list initial tabs @mcp-macos-latest-webkit
❌ [webkit] › mcp/tabs.spec.ts:47 › list first tab @mcp-macos-latest-webkit
❌ [webkit] › mcp/tabs.spec.ts:81 › create new tab with url @mcp-macos-latest-webkit
❌ [webkit] › mcp/tabs.spec.ts:94 › select tab @mcp-macos-latest-webkit
❌ [webkit] › mcp/tabs.spec.ts:123 › close tab @mcp-macos-latest-webkit
❌ [webkit] › mcp/tabs.spec.ts:36 › list initial tabs @mcp-windows-latest-webkit
❌ [webkit] › mcp/tabs.spec.ts:47 › list first tab @mcp-windows-latest-webkit
❌ [webkit] › mcp/tabs.spec.ts:81 › create new tab with url @mcp-windows-latest-webkit
❌ [webkit] › mcp/tabs.spec.ts:94 › select tab @mcp-windows-latest-webkit
❌ [webkit] › mcp/tabs.spec.ts:123 › close tab @mcp-windows-latest-webkit
❌ [webkit] › mcp/tabs.spec.ts:36 › list initial tabs @mcp-ubuntu-latest-webkit
❌ [webkit] › mcp/tabs.spec.ts:47 › list first tab @mcp-ubuntu-latest-webkit
❌ [webkit] › mcp/tabs.spec.ts:81 › create new tab with url @mcp-ubuntu-latest-webkit
❌ [webkit] › mcp/tabs.spec.ts:94 › select tab @mcp-ubuntu-latest-webkit
❌ [webkit] › mcp/tabs.spec.ts:123 › close tab @mcp-ubuntu-latest-webkit

8076 passed, 1361 skipped

Merge workflow run.

github-actions · 2026-08-21T23:55:03Z

🔴 The MCP failures are caused by this PR

Hi, I'm the Playwright bot and I took a look at the failing CI. The 66 MCP failures all trace to the new (visible to user) marker this PR adds to browser_tabs output: only tabs.spec.ts / crash.spec.ts snapshots were updated, and since page.tabInfo() returns null off Chromium, the marker splits by browser and the un-updated snapshots mismatch. The tests 1 job is clean (3 flaky, 0 failed). The lone cli-mouse mousewheel failure is a pre-existing flake.

Details

Overall: renderTabsMarkdown now appends (visible to user) when tab.page.tabInfo()?.active is truthy (tools/backend/tabs.ts, tools/backend/response.ts). tabInfo() returns null on non-Chromium engines, older Chromium and the headless shell, so the marker appears only on Chromium-family channels. The snapshots weren't reconciled with that split.

Caused by this PR

mcp/tabs.spec.ts:36,47,81,94,123 — Firefox and WebKit only. The PR updated these expectations to include (visible to user), but tabInfo() returns null on non-Chromium engines, so the marker is never emitted and expected/actual diverge. They pass on Chromium (where the marker does appear), which is why Chromium isn't in this group.
mcp/cli-json.spec.ts:123,133,144 (tab-new / tab-list / tab-close), mcp/screenshot.spec.ts:405 (browser_take_screenshot viewport without snapshot), mcp/cli-devtools.spec.ts:217 (video-start-stop) — chrome / chromium / msedge only. These snapshots were not touched by the PR, so they still expect the old - N: (current) [...] lines. On Chromium-family channels tabInfo().active is now truthy, the output gains (visible to user), and no longer matches. They pass on Firefox/WebKit (marker absent).

The two groups are mirror images of one root cause. Reconciling every browser_tabs / tab-list snapshot with tabInfo()'s per-browser behaviour — only expecting (visible to user) where tabInfo() reports active, and updating the un-touched cli-json / screenshot / cli-devtools Chromium snapshots — should clear all 65 of these.

Pre-existing flake / infra

[firefox] › mcp/cli-mouse.spec.ts:38 › mousewheel (@mcp-windows-latest-firefox) — pre-existing flake, unrelated to this PR. In the aggregated results this test failed on Firefox in 4 of 724 runs (~0.6%), on unrelated PRs (#42250 sha 3f1f652a, #42322 sha 810ce801) the PR can't be responsible for, and never failed on chrome/chromium/webkit/msedge. This PR only touches tab-strip rendering, which the mousewheel flow doesn't exercise.

Not a real failure

The tests 1 shard reported only 3 flaky tests (video+trace screencast, screencast frames fit, ui-mode-trace state update) and zero failures.

_{Triaged by the Playwright bot.}

_{Triaged by the Playwright bot - agent run}

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chore(chromium): trim tabInfo comments

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Yury Semikhatsky (yury-s) mentioned this pull request Aug 22, 2026

[Feature]: Expose Chromium foreground-tab and tab-strip metadata (Chrome 150+) #41873

Closed

Yury Semikhatsky (yury-s) closed this Aug 22, 2026

This was referenced Sep 1, 2026

Revert "fix(mcp): drop the backend after browser_close with a shared browser" #42492

Merged

fix(fetch): preserve node error fields across serialization #42562

Merged

github-actions Bot mentioned this pull request Sep 23, 2026

chore(proxy): drop legacy 'per-context' launch proxy handling #42892

Merged

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feat(chromium): expose tab strip metadata via page.tabInfo() - #42355

feat(chromium): expose tab strip metadata via page.tabInfo()#42355
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Yury Semikhatsky (yury-s) commented Aug 21, 2026

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Yury Semikhatsky (yury-s) commented Aug 21, 2026

Summary

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github-actions Bot commented Aug 21, 2026

Test results for "tests 1"

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github-actions Bot commented Aug 21, 2026

Test results for "MCP"

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github-actions Bot commented Aug 21, 2026

🔴 The MCP failures are caused by this PR

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