Setup installed `playwright@latest` and `@playwright/cli@latest` together.
Verified on a real container, that produces a tree that looks right and is
broken: `@playwright/cli@0.1.18` pins `playwright-core@1.63.0-alpha`, npm
hoists it, and `playwright@latest` (1.62.1) nests its own
`playwright-core@1.62.1` beside it. The two cores want different browser
revisions.
The browser step runs the *resolved* — hoisted — CLI, so it downloads
chromium-1237. Every script Claude writes says `require("playwright")`,
gets the nested 1.62.1, and dies with:
Executable doesn't exist at …/chromium_headless_shell-1234/…
while the pane reports a browser installed, because one is. This is
deterministic, not bad luck: every container set up through the pane
lands in it.
So the viewer package is installed first, and the `playwright` version
installed after it is the one that package pins — read from the manifest
npm just wrote, falling back to `@latest` only if it cannot be read. One
core, one browser revision, both halves agreeing. Re-running "Set up
Playwright" repairs an already-split tree.
Detection now asks the question directly rather than listing a cache: it
asks each resolved copy for `chromium.executablePath()` and whether that
file exists — the viewer's copy *and* the one `require("playwright")`
returns, since those are routinely different. `needs_browser()` covers
"installed but not launchable", and the pane names both halves instead of
saying "install a browser" over a cache that visibly has one.
An absent field is "the probe didn't answer", never "skewed": containers
predating these fields must not be told their browsers are wrong. The
Rust side gets that from Option; the TypeScript mirror needed `!= null`,
which an existing test caught.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>