diff --git a/build-tester/requirements.txt b/build-tester/requirements.txt
index fd65b45..ac1d734 100644
--- a/build-tester/requirements.txt
+++ b/build-tester/requirements.txt
@@ -1,5 +1,5 @@
 cloverlabs-camoufox
-# 1.61 sends viewport.isMobile in Browser.setDefaultViewport, which this
-# juggler's protocol schema rejects -- every context creation fails. Matches the
-# cap in pythonlib/pyproject.toml.
-playwright<1.61
+# 1.61 sent viewport.isMobile in Browser.setDefaultViewport, which this
+# juggler's protocol schema rejected; the schema now accepts it, so the cap
+# moves up rather than away. Matches the cap in pythonlib/pyproject.toml.
+playwright<1.63
diff --git a/pythonlib/pyproject.toml b/pythonlib/pyproject.toml
index 6ed013f..cf3af3f 100644
--- a/pythonlib/pyproject.toml
+++ b/pythonlib/pyproject.toml
@@ -33,7 +33,12 @@ rich = "*"
 requests = "*"
 orjson = "*"
 browserforge = "^1.2.4"
-playwright = "*"
+# Keep a ceiling. 1.61 added Juggler params the protocol schema had to learn
+# (viewport isMobile/screenSize, webp screenshots, webSocketFrame timestamps)
+# and every Playwright minor is free to change Juggler again, while
+# camoufox.server imports playwright._impl._driver -- a private API with no
+# compat guarantee. Bump deliberately, with a run of `make tests`.
+playwright = "<1.63"
 pyyaml = "*"
 platformdirs = "*"
 numpy = "*"