diff --git a/.github/workflows/hitl.yml b/.github/workflows/hitl.yml
index f59e8d2..b8611d4 100644
--- a/.github/workflows/hitl.yml
+++ b/.github/workflows/hitl.yml
@@ -1,9 +1,9 @@
 name: HITL
 
 on:
-  push:
-    branches: [ hitl ]
   workflow_dispatch:
+  pull_request:
+    branches: [ master ]
 
 jobs:
   hitl:
diff --git a/hitl/README.md b/hitl/README.md
new file mode 100644
index 0000000..629b587
--- /dev/null
+++ b/hitl/README.md
@@ -0,0 +1,25 @@
+# Stabilizer HITL Testing
+
+This directory contains tooling required for Stabilizer hardware-in-the-loop (HITL) testing.
+
+There is a `Stabilizer` board connected at the Quartiq office that is accessible via a private HITL
+repository in order to provide secure hardware testing of the stabilizer application in a public
+repository.
+
+**Note**: In order to ensure application security, all HITL runs must first be approved by a Quartiq
+representative before execution.
+
+# Configuration
+* Stabilizer is configured with an ethernet connection to a router. The router runs a DHCP server for
+the local network, and ensures that the Stabilizer used for these tests is available under the hostname `stabilizer-hitl`.
+* An MQTT broker is running at the hostname `mqtt`.
+
+# HITL Workflow
+The private HITL repository does the following:
+
+1. Check out this repository
+2. Build firmware images using Cargo
+3. Program stabilizer
+4. Execute `hitl/run.sh`
+
+In order to add new HITL tests, update `run.sh` to include the necessary tests.
diff --git a/hitl/run.sh b/hitl/run.sh
new file mode 100755
index 0000000..a01a472
--- /dev/null
+++ b/hitl/run.sh
@@ -0,0 +1,25 @@
+#!/bin/bash
+
+# Title:
+#   Stabilizer hardware-in-the-loop (HITL) test script.
+#
+# Description:
+#   This shell file is executed by the hardware runner in Quartiq's office to exercise the various
+#   hardware aspects of Stabilizer.
+
+# Enable shell operating mode flags.
+set -eux
+
+# Set up python for testing
+python3 -m venv --system-site-packages py
+. py/bin/activate
+python3 -m pip install -r requirements.txt
+
+# Test pinging Stabilizer. This exercises that:
+# * DHCP is functional and an IP has been acquired
+# * Stabilizer's network is functioning as intended
+# * The stabilizer application is operational
+ping -c 5 -w 20 stabilizer-hitl
+
+# Test the MQTT interface.
+python3 miniconf.py dt/sinara/stabilizer afe/0 '"G2"'
diff --git a/requirements.txt b/requirements.txt
new file mode 100644
index 0000000..a3d7fef
--- /dev/null
+++ b/requirements.txt
@@ -0,0 +1 @@
+gmqtt