diff --git a/Teamcity-Phabricator-Plugin/phabricator-plugin-agent/src/main/java/uk/xlab/teamcity/phabricator/AgentBuildExtension.java b/Teamcity-Phabricator-Plugin/phabricator-plugin-agent/src/main/java/uk/xlab/teamcity/phabricator/AgentBuildExtension.java
index 8a2a89c..b88e9f0 100644
--- a/Teamcity-Phabricator-Plugin/phabricator-plugin-agent/src/main/java/uk/xlab/teamcity/phabricator/AgentBuildExtension.java
+++ b/Teamcity-Phabricator-Plugin/phabricator-plugin-agent/src/main/java/uk/xlab/teamcity/phabricator/AgentBuildExtension.java
@@ -16,6 +16,7 @@ import uk.xlab.teamcity.phabricator.logging.PhabricatorAgentLogger;
 
 public class AgentBuildExtension extends AgentLifeCycleAdapter {
 
+    private static final String OUTPUT_PREFIX = "Phabricator Plugin - %s";
     private PhabricatorAgentLogger agentLogLogger;
     private BuildProgressLogger buildLogger;
     private PhabricatorPluginConfig phabricatorConfig;
@@ -57,12 +58,26 @@ public class AgentBuildExtension extends AgentLifeCycleAdapter {
         // everything is present and correct for us to continue
         if (!phabricatorConfig.isPluginSetup()) {
             agentLogLogger.info("Plugin incorrectly configured");
+            phabricatorTriggeredBuild = false;
             return;
         }
 
         phabricatorTriggeredBuild = true;
         agentLogLogger.info("Plugin ready");
-        buildLogger.message("Phabricator Plugin - Active");
+        buildLogger.message(String.format(OUTPUT_PREFIX, "Active"));
+
+        buildLogger.message(String.format(OUTPUT_PREFIX, String.format("%s: %s", Constants.PHABRICATOR_URL_SETTING,
+                phabricatorConfig.getPhabricatorURL().toString())));
+        buildLogger.message(String.format(OUTPUT_PREFIX, String.format("%s: %s",
+                Constants.PHABRICATOR_ARCANIST_PATH_SETTING, phabricatorConfig.getPathToArcanist())));
+        buildLogger.message(String.format(OUTPUT_PREFIX,
+                String.format("%s: %s", Constants.BUILD_ID, phabricatorConfig.getBuildId())));
+        buildLogger.message(String.format(OUTPUT_PREFIX,
+                String.format("%s: %s", Constants.DIFF_ID, phabricatorConfig.getDiffId())));
+        buildLogger.message(String.format(OUTPUT_PREFIX, String.format("%s: %s", Constants.HARBORMASTER_PHID,
+                phabricatorConfig.getPhabricatorURL().toString())));
+        buildLogger.message(String.format(OUTPUT_PREFIX,
+                String.format("%s: %s", Constants.REVISION_ID, phabricatorConfig.getRevisionId())));
     }
 
     @Override
@@ -72,7 +87,17 @@ public class AgentBuildExtension extends AgentLifeCycleAdapter {
             return;
         }
 
-        buildLogger.message("PHAB: SOURCES HAVE UPDATED");
-        agentLogLogger.info("PHAB: SOURCES HAVE UPDATED");
+        buildLogger.message(String.format(OUTPUT_PREFIX, "Attempting arc patch"));
+        agentLogLogger.info("Attempting arc patch");
+
+        ArcanistClient arcanistClient = new ArcanistClient(phabricatorConfig.getPathToArcanist(),
+                runningBuild.getCheckoutDirectory().getPath(), phabricatorConfig.getPhabricatorURL().toString(),
+                phabricatorConfig.getConduitToken(), agentLogLogger);
+
+        int patchCode = arcanistClient.patch(phabricatorConfig.getDiffId());
+
+        if (patchCode > 0) {
+            runningBuild.stopBuild("Patch failed to apply. Check the agent output log for patch failure detals.");
+        }
     }
 }
diff --git a/Teamcity-Phabricator-Plugin/phabricator-plugin-agent/src/main/java/uk/xlab/teamcity/phabricator/ArcanistClient.java b/Teamcity-Phabricator-Plugin/phabricator-plugin-agent/src/main/java/uk/xlab/teamcity/phabricator/ArcanistClient.java
new file mode 100644
index 0000000..5c25b66
--- /dev/null
+++ b/Teamcity-Phabricator-Plugin/phabricator-plugin-agent/src/main/java/uk/xlab/teamcity/phabricator/ArcanistClient.java
@@ -0,0 +1,50 @@
+package uk.xlab.teamcity.phabricator;
+
+import uk.xlab.teamcity.phabricator.logging.PhabricatorAgentLogger;
+
+public class ArcanistClient {
+
+    private final String arcPath;
+    private final String workingDir;
+    private final String conduitAPI;
+    private final String token;
+
+    private final PhabricatorAgentLogger agentLogLogger;
+
+    public ArcanistClient(
+            final String pathToArcanist,
+            final String workingDirectory,
+            final String phabricatorURL,
+            final String conduitToken,
+            final PhabricatorAgentLogger logger
+    ) {
+        arcPath = pathToArcanist;
+        workingDir = workingDirectory;
+        conduitAPI = phabricatorURL;
+        token = conduitToken;
+        agentLogLogger = logger;
+    }
+
+    public int patch(String diffId) {
+        try {
+
+            Command commandToExecute = new CommandBuilder()
+                    .setCommand(arcPath)
+                    .setAction("patch")
+                    .setWorkingDir(workingDir)
+                    .setArg("--diff")
+                    .setArg(diffId)
+                    .setFlagWithValueEquals("--conduit-uri", conduitAPI)
+                    .setFlagWithValueEquals("--conduit-token", token)
+                    .build();
+            return commandToExecute.executeAndWait();
+
+        } catch (IllegalArgumentException e) {
+            agentLogLogger.warn("Building command failed", e);
+        } catch (Exception e) {
+            agentLogLogger.warn("Patching error", e);
+        }
+
+        return 1;
+    }
+}
diff --git a/Teamcity-Phabricator-Plugin/phabricator-plugin-common/src/main/java/uk/xlab/teamcity/phabricator/PhabricatorPluginConfig.java b/Teamcity-Phabricator-Plugin/phabricator-plugin-common/src/main/java/uk/xlab/teamcity/phabricator/PhabricatorPluginConfig.java
index e80db73..91f4ad0 100644
--- a/Teamcity-Phabricator-Plugin/phabricator-plugin-common/src/main/java/uk/xlab/teamcity/phabricator/PhabricatorPluginConfig.java
+++ b/Teamcity-Phabricator-Plugin/phabricator-plugin-common/src/main/java/uk/xlab/teamcity/phabricator/PhabricatorPluginConfig.java
@@ -48,6 +48,15 @@ public class PhabricatorPluginConfig {
      * @param parameters
      */
     public void setParameters(Map<String, String> parameters) {
+        // Clear the class variables to avoid any lingering references
+        phabricatorUrl = null;
+        conduitToken = null;
+        pathToArcanist = null;
+        buildId = null;
+        diffId = null;
+        harbormasterPHID = null;
+        revisionId = null;
+
         params = parameters;
 
         logger.info("Looking for parameters");
@@ -71,7 +80,8 @@ public class PhabricatorPluginConfig {
                     conduitToken = params.get(Constants.PHABRICATOR_CONDUIT_TOKEN_SETTING);
                     break;
                 case Constants.PHABRICATOR_ARCANIST_PATH_SETTING:
-                    logger.info(String.format("Found Phabricator Arcanist Path: %s", params.get(Constants.PHABRICATOR_ARCANIST_PATH_SETTING)));
+                    logger.info(String.format("Found Phabricator Arcanist Path: %s",
+                            params.get(Constants.PHABRICATOR_ARCANIST_PATH_SETTING)));
                     pathToArcanist = params.get(Constants.PHABRICATOR_ARCANIST_PATH_SETTING);
                     break;
                 case Constants.BUILD_ID:
@@ -116,10 +126,26 @@ public class PhabricatorPluginConfig {
         return conduitToken;
     }
 
+    public String getPathToArcanist() {
+        return pathToArcanist;
+    }
+
+    public String getBuildId() {
+        return buildId;
+    }
+
+    public String getDiffId() {
+        return diffId;
+    }
+
     public String getHarbormasterPHID() {
         return harbormasterPHID;
     }
 
+    public String getRevisionId() {
+        return revisionId;
+    }
+
     private URL parsePhabricatorURL(String input) throws MalformedURLException {
         URL inputURL = new URL(input);
         return inputURL;