diff --git a/tools/mcc-debug.sh b/tools/mcc-debug.sh
index d0ca0e78..769ff4cc 100644
--- a/tools/mcc-debug.sh
+++ b/tools/mcc-debug.sh
@@ -42,7 +42,6 @@ DO_BUILD=true
 DEBUG_ON=false
 FILE_INPUT=false
 BUILD_ROOT="$(_mcc_build_root)"
-BUILD_ROOT_ENV_PREFIX=""
 
 while [[ $# -gt 0 ]]; do
     case "$1" in
@@ -102,8 +101,6 @@ fi
 
 if [[ "${MCC_BUILD_MODE:-local}" == "tmpfs" ]]; then
     mkdir -p "$BUILD_ROOT"
-    printf -v BUILD_ROOT_QUOTED '%q' "$BUILD_ROOT"
-    BUILD_ROOT_ENV_PREFIX="MCC_BUILD_ROOT=$BUILD_ROOT_QUOTED "
 fi
 
 SESSION_ROOT="$(_mcc_session_root "$SESSION")"
@@ -224,11 +221,25 @@ rm -f "$PID_FILE"
 MCC_ARGS=("$CFG" "$USERNAME" "-" "localhost:$PORT")
 MCC_ARGS_CMD="$(printf '%q ' "${MCC_ARGS[@]}")"
 
+RUNTIME_APP="$(_mcc_runtime_app_path || true)"
+if [[ -z "$RUNTIME_APP" ]]; then
+    echo "  Failed to find built MCC runtime under $(_mcc_runtime_output_dir)" >&2
+    echo "  Build first with: source tools/mcc-env.sh && mcc-build" >&2
+    exit 1
+fi
+
+if [[ "$RUNTIME_APP" == *.dll ]]; then
+    MCC_LAUNCHER=(dotnet "$RUNTIME_APP")
+else
+    MCC_LAUNCHER=("$RUNTIME_APP")
+fi
+MCC_LAUNCHER_CMD="$(printf '%q ' "${MCC_LAUNCHER[@]}")"
+
 if [[ "$MODE" == "tui" ]]; then
     # TUI mode: needs a real tty - no pipes or redirects allowed
     tmux kill-session -t "$MCC_TMUX_SESSION" 2>/dev/null || true
     tmux new-session -d -s "$MCC_TMUX_SESSION" -x 160 -y 50 \
-        "cd '$REPO_ROOT' && ${BUILD_ROOT_ENV_PREFIX}dotnet run --project MinecraftClient -c Release --no-build -- $MCC_ARGS_CMD; echo '=== MCC EXITED ==='; sleep 600"
+        "cd '$REPO_ROOT' && $MCC_LAUNCHER_CMD $MCC_ARGS_CMD; echo '=== MCC EXITED ==='; sleep 600"
     echo ""
     echo "  TUI mode started in tmux session '$MCC_TMUX_SESSION'"
     echo "  (TUI mode uses a real terminal; log file is not available, use MCC's /debug command)"
@@ -241,7 +252,7 @@ elif $FILE_INPUT; then
     # FileInput mode: run in detached tmux, drive via session-specific input file
     tmux kill-session -t "$MCC_TMUX_SESSION" 2>/dev/null || true
     tmux new-session -d -s "$MCC_TMUX_SESSION" -x 160 -y 50 \
-        "cd '$REPO_ROOT' && printf '%s\n' \"\$\$\" > '$PID_FILE' && exec env ${BUILD_ROOT_ENV_PREFIX}MCC_FILE_INPUT=1 MCC_INPUT_FILE='$INPUT_FILE' dotnet run --project MinecraftClient -c Release --no-build -- $MCC_ARGS_CMD > '$MCC_LOG' 2>&1"
+        "cd '$REPO_ROOT' && printf '%s\n' \"\$\$\" > '$PID_FILE' && exec env MCC_FILE_INPUT=1 MCC_INPUT_FILE='$INPUT_FILE' $MCC_LAUNCHER_CMD $MCC_ARGS_CMD > '$MCC_LOG' 2>&1"
 
     for _ in $(seq 1 25); do
         if [[ -s "$PID_FILE" ]]; then
@@ -289,7 +300,7 @@ else
     # Interactive classic mode: run in tmux (no pipe - ConsoleInteractive also needs tty)
     tmux kill-session -t "$MCC_TMUX_SESSION" 2>/dev/null || true
     tmux new-session -d -s "$MCC_TMUX_SESSION" -x 160 -y 50 \
-        "cd '$REPO_ROOT' && ${BUILD_ROOT_ENV_PREFIX}dotnet run --project MinecraftClient -c Release --no-build -- $MCC_ARGS_CMD; echo '=== MCC EXITED ==='; sleep 600"
+        "cd '$REPO_ROOT' && $MCC_LAUNCHER_CMD $MCC_ARGS_CMD; echo '=== MCC EXITED ==='; sleep 600"
     echo ""
     echo "  Classic mode started in tmux session '$MCC_TMUX_SESSION'"
     echo ""
diff --git a/tools/mcc-env.sh b/tools/mcc-env.sh
index 437c5c9a..e05cb8a9 100644
--- a/tools/mcc-env.sh
+++ b/tools/mcc-env.sh
@@ -121,6 +121,29 @@ _mcc_build_root() {
   printf '%s\n' "$MCC_REPO_ROOT"
 }
 
+_mcc_runtime_output_dir() {
+  printf '%s/MinecraftClient/bin/Release/net10.0\n' "$(_mcc_build_root)"
+}
+
+_mcc_runtime_app_path() {
+  local runtime_dir runtime_host runtime_dll
+  runtime_dir="$(_mcc_runtime_output_dir)"
+  runtime_host="$runtime_dir/MinecraftClient"
+  runtime_dll="$runtime_dir/MinecraftClient.dll"
+
+  if [[ -x "$runtime_host" ]]; then
+    printf '%s\n' "$runtime_host"
+    return 0
+  fi
+
+  if [[ -f "$runtime_dll" ]]; then
+    printf '%s\n' "$runtime_dll"
+    return 0
+  fi
+
+  return 1
+}
+
 _mcc_dotnet_env() {
   if [[ "${MCC_BUILD_MODE:-local}" == "tmpfs" ]]; then
     local build_root
diff --git a/tools/test-mcc-env.sh b/tools/test-mcc-env.sh
index 38c50c84..ba7cf7e0 100755
--- a/tools/test-mcc-env.sh
+++ b/tools/test-mcc-env.sh
@@ -82,6 +82,26 @@ mkdir -p "$build_root/probe"
 mcc-build-clean
 [[ ! -e "$build_root/probe" ]]
 
+runtime_dir="$(_mcc_runtime_output_dir)"
+mkdir -p "$runtime_dir"
+printf '#!/usr/bin/env bash\n' > "$runtime_dir/MinecraftClient"
+chmod +x "$runtime_dir/MinecraftClient"
+printf '' > "$runtime_dir/MinecraftClient.dll"
+assert_eq "$runtime_dir/MinecraftClient" "$(_mcc_runtime_app_path)" "runtime apphost preferred"
+
+rm -f "$runtime_dir/MinecraftClient"
+assert_eq "$runtime_dir/MinecraftClient.dll" "$(_mcc_runtime_app_path)" "runtime dll fallback"
+
+rm -f "$runtime_dir/MinecraftClient.dll"
+set +e
+_mcc_runtime_app_path >/dev/null 2>&1
+status=$?
+set -e
+if [[ $status -eq 0 ]]; then
+    echo "FAIL: runtime app path resolved without runtime artifacts" >&2
+    exit 1
+fi
+
 session="wrapper-smoke"
 input_file="$(_mcc_session_input_file "$session")"
 rm -rf "$(_mcc_session_root "$session")"