diff --git a/egg/with-sidecar.sh b/egg/with-sidecar.sh
index 940294b..67d8199 100755
--- a/egg/with-sidecar.sh
+++ b/egg/with-sidecar.sh
@@ -16,6 +16,29 @@
 # the game's: nothing the bridge gets wrong — an unwritable log, a sidecar that will not start — may
 # keep the server from booting. Each step reports its own failure and the script goes on to `exec`.
 
+# Carbon's entrypoint puts LD_PRELOAD=libdoorstop.so in front of the WHOLE startup string, and with
+# Carbon's DOORSTOP_* environment that preloader breaks this shell's own `$(...)`: the child's output
+# goes straight to the console and the capture comes back empty. The phase 18 walk saw exactly that
+# on the first Carbon server built from the egg — the config JSON, token included, dumped raw to the
+# console, and an empty "server id 'main', sidecar URL http://<ip>:" line. Dropping LD_PRELOAD for
+# the sidecar alone is not enough; the shell doing the capturing has it too. So the script runs
+# once more without it, keeps it aside, and gives it back to the game — the one process that needs
+# it — in `run_game` below.
+if [ -n "${LD_PRELOAD-}" ] && [ -z "${RUNICGATEWAY_LAUNCHER_CLEAN-}" ]; then
+  exec env -u LD_PRELOAD RUNICGATEWAY_GAME_PRELOAD="$LD_PRELOAD" RUNICGATEWAY_LAUNCHER_CLEAN=1 \
+    sh "$0" "$@"
+fi
+
+# The game BECOMES this process: the panel console keeps its stdin and stdout, and stop still
+# stops the server, which takes the sidecar down with the container.
+run_game() {
+  if [ -n "${RUNICGATEWAY_GAME_PRELOAD-}" ]; then
+    export LD_PRELOAD="$RUNICGATEWAY_GAME_PRELOAD"
+  fi
+  unset RUNICGATEWAY_GAME_PRELOAD RUNICGATEWAY_LAUNCHER_CLEAN
+  exec "$@"
+}
+
 RL=/home/container/rust-link
 mkdir -p "$RL" 2>/dev/null
 
@@ -58,14 +81,14 @@ fi
 SIDECAR="$RL/rust-link-sidecar"
 if [ ! -x "$SIDECAR" ]; then
   echo "[rust-link] $SIDECAR is missing - reinstall the server to fetch the bridge. Starting the game without it."
-  exec "$@"
+  run_game "$@"
 fi
 
 # Provision first, so the token can be shown. `--print-config` resolves the configuration exactly as
 # a start does, writing sidecar.toml with a generated token when there is none; the JSON it prints
 # says whether it generated one on THIS call, which is what makes "print once" true (D152).
-# Tracing is off on that path, so stdout is only the document. LD_PRELOAD is dropped for the
-# sidecar in both calls: Carbon's entrypoint puts its Mono preloader in front of the whole startup.
+# Tracing is off on that path, so stdout is only the document. LD_PRELOAD is already gone from this
+# shell (see the top); `env -u` stays so a preload set some other way cannot reach the sidecar.
 if CFG="$(env -u LD_PRELOAD "$SIDECAR" --print-config 2>&1)"; then
   # The Nth `"key": "value"` line of the pretty-printed JSON. `bind` appears twice — game, then web.
   field() { printf '%s\n' "$CFG" | sed -n "s/^ *\"$1\": \"\([^\"]*\)\",\{0,1\}\$/\1/p" | sed -n "${2:-1}p"; }
@@ -98,6 +121,4 @@ else
   echo "[rust-link] $RL is not writable - the game starts without the sidecar."
 fi
 
-# The game BECOMES this process: the panel console keeps its stdin and stdout, and stop still
-# stops the server, which takes the sidecar down with the container.
-exec "$@"
+run_game "$@"