diff --git a/deploy/cosmic-clash-server b/deploy/cosmic-clash-server
index bb0152a0..96fbe9d6 100644
--- a/deploy/cosmic-clash-server
+++ b/deploy/cosmic-clash-server
@@ -3,4 +3,21 @@
 # is baked into the dedicated artifact during the Docker export stage.
 set -eu
 
+# Godot's stdout is fully (block) buffered rather than line-buffered whenever
+# it isn't attached to a TTY -- true of every real deployment of this script:
+# `docker run -d` (Docker's log driver presents a pipe, not a TTY), a plain
+# `docker run` even without -d, and systemd's journal capture (also a pipe).
+# Verified directly: a `docker run -d` container sat for 20+ seconds with
+# `docker logs` showing nothing at all, including the startup line, while the
+# process was confirmed alive and running; docker stop's SIGTERM (Godot has
+# no SIGTERM hook, see SERVER.md) then killed it without ever flushing that
+# buffered output, losing it permanently rather than merely delaying it.
+# `stdbuf -oL -eL` forces line buffering via LD_PRELOAD without touching the
+# binary; re-verified the same scenario then shows the startup line within
+# 3s. Fall back to running unwrapped if stdbuf isn't available (e.g. a
+# minimal image without GNU coreutils) rather than failing to start at all --
+# a server with delayed logs is still far better than no server.
+if command -v stdbuf >/dev/null 2>&1; then
+    exec stdbuf -oL -eL "$(dirname "$0")/CosmicClashServer.x86_64" --headless -- "$@"
+fi
 exec "$(dirname "$0")/CosmicClashServer.x86_64" --headless -- "$@"