diff --git a/flake.nix b/flake.nix
--- a/flake.nix
+++ b/flake.nix
@@ -13,6 +13,7 @@
       localOverlay = import ./nix/overlay.nix;
       overlays = [
         localOverlay
+        (_: _: { commSrc = toString self; } )
       ];
 
       # Since we build for many systems (e.g. aarch64, x86_64-linux), we
diff --git a/nix/rabbitmq-up-mac.nix b/nix/rabbitmq-up-mac.nix
--- a/nix/rabbitmq-up-mac.nix
+++ b/nix/rabbitmq-up-mac.nix
@@ -1,6 +1,7 @@
 { lib
 , rabbitmq-server
 , writeShellApplication
+, commSrc
 }:
 
 # writeShellApplication is a "writer helper" which
@@ -13,10 +14,10 @@
     RABBITMQ_HOME=''${XDG_DATA_HOME:-$HOME/.local/share}/RabbitMQ
     RABBITMQ_PIDFILE=''${RABBITMQ_HOME}/rabbitmq.pid
 
-    "${../scripts/start_comm_daemon.sh}" \
-      rabbitmq-server \
+    "${commSrc}/scripts/start_comm_daemon.sh" \
+      beam.smp \
       RabbitMQ \
-      "${../scripts/start_rabbitmq.sh}" \
+      "${commSrc}/scripts/start_rabbitmq.sh" \
       "$RABBITMQ_PIDFILE"
 
     # Explicitly exit this script so the parent shell can determine
diff --git a/scripts/start_rabbitmq.sh b/scripts/start_rabbitmq.sh
--- a/scripts/start_rabbitmq.sh
+++ b/scripts/start_rabbitmq.sh
@@ -2,8 +2,14 @@
 
 set -eou pipefail
 
+if ! command -v rabbitmq-server > /dev/null; then
+  echo "Please install rabbitmq-server or run 'nix develop'" >&2
+  exit 1
+fi
+
 SCRIPT_DIR=$(cd "$(dirname "$0")"; pwd -P)
 
+# shellcheck source=/dev/null
 source "${SCRIPT_DIR}/source_development_defaults.sh"
 
 # RabbitMQ is mostly configured through environment variables
@@ -14,4 +20,4 @@
 echo "Kill RabbitMQ server: pkill rabbitmq-server beam.smp" >&2
 
 # 'exec' allows for us to replace bash process with RabbitMQ
-exec "rabbitmq-server" > "$RABBITMQ_LOG_BASE/startup.log"
+exec rabbitmq-server > "$RABBITMQ_LOG_BASE/startup.log"