diff --git a/scripts/test-a11y.sh b/scripts/test-a11y.sh
index e42b363..7aa36bd 100755
--- a/scripts/test-a11y.sh
+++ b/scripts/test-a11y.sh
@@ -18,7 +18,7 @@ cleanup() {
 }
 trap cleanup EXIT INT TERM
 
-CI=1 npx @wp-playground/cli@latest server --auto-mount --login --port="$PORT" \
+CI=1 npx @wp-playground/cli@3.1.40 server --auto-mount --login --port="$PORT" \
 	>"$LOG_FILE" 2>&1 &
 PLAYGROUND_PID=$!
 
diff --git a/scripts/test-lifecycle-e2e.sh b/scripts/test-lifecycle-e2e.sh
index ea95e5f..ff26925 100755
--- a/scripts/test-lifecycle-e2e.sh
+++ b/scripts/test-lifecycle-e2e.sh
@@ -36,13 +36,13 @@ cleanup() {
 trap cleanup EXIT INT TERM
 
 # Start server 1 (auto-mount — plugin source is read-write mounted).
-CI=1 npx @wp-playground/cli@latest server \
+CI=1 npx @wp-playground/cli@3.1.40 server \
 	--auto-mount --login --port="$PORT_MOUNT" \
 	>"$LOG_MOUNT" 2>&1 &
 PID_MOUNT=$!
 
 # Start server 2 (plain — no plugin pre-installed; test uploads the zip).
-CI=1 npx @wp-playground/cli@latest server \
+CI=1 npx @wp-playground/cli@3.1.40 server \
 	--login --port="$PORT_ZIP" \
 	>"$LOG_ZIP" 2>&1 &
 PID_ZIP=$!
diff --git a/scripts/test-playground-e2e.sh b/scripts/test-playground-e2e.sh
index 5daa086..345a826 100644
--- a/scripts/test-playground-e2e.sh
+++ b/scripts/test-playground-e2e.sh
@@ -18,7 +18,7 @@ cleanup() {
 }
 trap cleanup EXIT INT TERM
 
-CI=1 npx @wp-playground/cli@latest server --auto-mount --login --port="$PORT" >"$LOG_FILE" 2>&1 &
+CI=1 npx @wp-playground/cli@3.1.40 server --auto-mount --login --port="$PORT" >"$LOG_FILE" 2>&1 &
 PLAYGROUND_PID=$!
 
 attempt=0
diff --git a/scripts/test-smoke-e2e.sh b/scripts/test-smoke-e2e.sh
index c64377e..48c580e 100755
--- a/scripts/test-smoke-e2e.sh
+++ b/scripts/test-smoke-e2e.sh
@@ -19,7 +19,7 @@ cleanup() {
 }
 trap cleanup EXIT INT TERM
 
-CI=1 npx @wp-playground/cli@latest server \
+CI=1 npx @wp-playground/cli@3.1.40 server \
 	--auto-mount --login --port="$PORT" --blueprint="$BLUEPRINT_FILE" \
 	>"$LOG_FILE" 2>&1 &
 PLAYGROUND_PID=$!