diff --git a/.arcconfig b/.arcconfig
--- a/.arcconfig
+++ b/.arcconfig
@@ -6,5 +6,6 @@
   "git:arc.feature.start.default" : "origin/master",
   "arc.feature.start.default" : "master",
   "history.immutable" : false,
-  "load" : ["arcanist"]
+  "load" : ["arcanist"],
+  "arcanist_configuration" : "ArcanistBitcoinABCConfiguration"
 }
diff --git a/arcanist/.phutil_module_cache b/arcanist/.phutil_module_cache
--- a/arcanist/.phutil_module_cache
+++ b/arcanist/.phutil_module_cache
@@ -1 +1 @@
-{"__symbol_cache_version__":11,"d60c8224f471e0ecddc2a6f3c6839cd1":{"have":{"class":{"AutoPEP8FormatLinter":75}},"need":{"function":{"pht":297,"id":1317},"class":{"ArcanistExternalLinter":104,"ArcanistLintMessage":1324,"Filesystem":1168,"ArcanistLinter":1431,"ArcanistLintSeverity":1509}},"xmap":{"AutoPEP8FormatLinter":["ArcanistExternalLinter"]}},"213c3145da34ed6dfc0d70d628a2a086":{"have":{"class":{"CheckDocLinter":106}},"need":{"function":{"pht":323,"id":1868},"class":{"ArcanistExternalLinter":129,"ArcanistLintMessage":1875,"Filesystem":737,"ArcanistLinter":1923,"ArcanistLintSeverity":2009}},"xmap":{"CheckDocLinter":["ArcanistExternalLinter"]}},"7bab1f879b8a86dd9977b8c0d075935f":{"have":{"class":{"ClangFormatLinter":79}},"need":{"function":{"pht":302,"execx":787,"id":1664},"class":{"ArcanistExternalLinter":105,"ArcanistLintMessage":1671,"Filesystem":1515,"ArcanistLinter":1778,"ArcanistLintSeverity":1856}},"xmap":{"ClangFormatLinter":["ArcanistExternalLinter"]}},"0e068a1116ed03e86a2388020a821983":{"have":{"class":{"PythonFormatLinter":75}},"need":{"function":{"pht":305,"id":1614},"class":{"ArcanistExternalLinter":102,"ArcanistLintMessage":1621,"Filesystem":733,"ArcanistLinter":1752,"ArcanistLintSeverity":1835}},"xmap":{"PythonFormatLinter":["ArcanistExternalLinter"]}},"ea2beb1668dfbdd87488f18fbb20178f":{"have":{"class":{"TestsLinter":103}},"need":{"function":{"pht":318,"id":2676},"class":{"ArcanistExternalLinter":123,"ArcanistLintMessage":2683,"Filesystem":791,"ArcanistLinter":2731,"ArcanistLintSeverity":2839}},"xmap":{"TestsLinter":["ArcanistExternalLinter"]}}}
\ No newline at end of file
+{"__symbol_cache_version__":11,"d60c8224f471e0ecddc2a6f3c6839cd1":{"have":{"class":{"AutoPEP8FormatLinter":75}},"need":{"function":{"pht":297,"id":1317},"class":{"ArcanistExternalLinter":104,"ArcanistLintMessage":1324,"Filesystem":1168,"ArcanistLinter":1431,"ArcanistLintSeverity":1509}},"xmap":{"AutoPEP8FormatLinter":["ArcanistExternalLinter"]}},"213c3145da34ed6dfc0d70d628a2a086":{"have":{"class":{"CheckDocLinter":106}},"need":{"function":{"pht":323,"id":1868},"class":{"ArcanistExternalLinter":129,"ArcanistLintMessage":1875,"Filesystem":737,"ArcanistLinter":1923,"ArcanistLintSeverity":2009}},"xmap":{"CheckDocLinter":["ArcanistExternalLinter"]}},"7bab1f879b8a86dd9977b8c0d075935f":{"have":{"class":{"ClangFormatLinter":79}},"need":{"function":{"pht":302,"execx":787,"id":1664},"class":{"ArcanistExternalLinter":105,"ArcanistLintMessage":1671,"Filesystem":1515,"ArcanistLinter":1778,"ArcanistLintSeverity":1856}},"xmap":{"ClangFormatLinter":["ArcanistExternalLinter"]}},"e3132d407656d565ce80d359f4f0fe5f":{"have":{"class":{"PythonFormatLinter":124}},"need":{"function":{"pht":354,"id":1845},"class":{"ArcanistExternalLinter":151,"ArcanistLintMessage":1852,"Filesystem":777,"ArcanistLinter":1977,"ArcanistLintSeverity":2060}},"xmap":{"PythonFormatLinter":["ArcanistExternalLinter"]}},"ea2beb1668dfbdd87488f18fbb20178f":{"have":{"class":{"TestsLinter":103}},"need":{"function":{"pht":318,"id":2676},"class":{"ArcanistExternalLinter":123,"ArcanistLintMessage":2683,"Filesystem":791,"ArcanistLinter":2731,"ArcanistLintSeverity":2839}},"xmap":{"TestsLinter":["ArcanistExternalLinter"]}},"74a84e54995fbefdfd6b55cb8a57f57f":{"have":{"class":{"ArcanistBitcoinABCConfiguration":13}},"need":{"class":{"ArcanistConfiguration":53},"class\/interface":{"ArcanistWorkflow":122}},"xmap":{"ArcanistBitcoinABCConfiguration":["ArcanistConfiguration"]}},"2677f95ae93348c53cdab5ed15d78095":{"have":{"class":{"LocaleDependenceLinter":155}},"need":{"function":{"pht":571,"id":3291},"class":{"ArcanistExternalLinter":186,"ArcanistLintMessage":3298,"Filesystem":1041,"ArcanistLinter":3348,"ArcanistLintSeverity":3507}},"xmap":{"LocaleDependenceLinter":["ArcanistExternalLinter"]}},"8b6ad3dbb733e91406c473640377beed":{"have":{"class":{"ArcanistScriptedDiffWorkflow":59}},"need":{"function":{"phutil_console_format":714,"pht":1340,"id":2372},"class":{"ArcanistWorkflow":96,"TempFile":2379,"ExecFuture":2845,"PhutilConsole":1708,"Filesystem":2407}},"xmap":{"ArcanistScriptedDiffWorkflow":["ArcanistWorkflow"]}}}
\ No newline at end of file
diff --git a/arcanist/__phutil_library_map__.php b/arcanist/__phutil_library_map__.php
--- a/arcanist/__phutil_library_map__.php
+++ b/arcanist/__phutil_library_map__.php
@@ -9,6 +9,8 @@
 phutil_register_library_map(array(
   '__library_version__' => 2,
   'class' => array(
+    'ArcanistBitcoinABCConfiguration' => 'configuration/ArcanistBitcoinABCConfiguration.php',
+    'ArcanistScriptedDiffWorkflow' => 'workflow/ArcanistScriptedDiffWorkflow.php',
     'AutoPEP8FormatLinter' => 'linter/AutoPEP8Linter.php',
     'CheckDocLinter' => 'linter/CheckDocLinter.php',
     'ClangFormatLinter' => 'linter/ClangFormatLinter.php',
@@ -17,6 +19,8 @@
   ),
   'function' => array(),
   'xmap' => array(
+    'ArcanistBitcoinABCConfiguration' => 'ArcanistConfiguration',
+    'ArcanistScriptedDiffWorkflow' => 'ArcanistWorkflow',
     'AutoPEP8FormatLinter' => 'ArcanistExternalLinter',
     'CheckDocLinter' => 'ArcanistExternalLinter',
     'ClangFormatLinter' => 'ArcanistExternalLinter',
diff --git a/arcanist/configuration/ArcanistBitcoinABCConfiguration.php b/arcanist/configuration/ArcanistBitcoinABCConfiguration.php
new file mode 100644
--- /dev/null
+++ b/arcanist/configuration/ArcanistBitcoinABCConfiguration.php
@@ -0,0 +1,13 @@
+<?php
+
+class ArcanistBitcoinABCConfiguration extends ArcanistConfiguration {
+
+  public function willRunWorkflow($command, ArcanistWorkflow $workflow) {
+    /* Run arc scripted-diff before arc diff */
+    if ($command === 'diff') {
+      $scriptedDiff = $workflow->buildChildWorkflow('scripted-diff', array());
+      return $scriptedDiff->run();
+    }
+    return 0;
+  }
+}
diff --git a/arcanist/workflow/ArcanistScriptedDiffWorkflow.php b/arcanist/workflow/ArcanistScriptedDiffWorkflow.php
new file mode 100644
--- /dev/null
+++ b/arcanist/workflow/ArcanistScriptedDiffWorkflow.php
@@ -0,0 +1,172 @@
+<?php
+
+/**
+ * Check scripted diff.validity
+ */
+final class ArcanistScriptedDiffWorkflow extends ArcanistWorkflow {
+  const SCRIPTED_DIFF_START = '-BEGIN VERIFY SCRIPT-';
+  const SCRIPTED_DIFF_END = '-END VERIFY SCRIPT-';
+
+  const RESULT_OKAY = 0;
+  const RESULT_WARNINGS = 1;
+  const RESULT_ERRORS = 2;
+  const RESULT_SKIP = 3;
+
+  private function getScriptFromCommitMessage($message) {
+    if (preg_match(
+        '/'.self::SCRIPTED_DIFF_START.'(.+)'.self::SCRIPTED_DIFF_END.'/s',
+        $message, $matches)) {
+      return ltrim($matches[1]);
+    }
+
+    return null;
+  }
+
+  public function getWorkflowName() {
+    return 'scripted-diff';
+  }
+
+  public function getCommandSynopses() {
+    return phutil_console_format(<<<EOTEXT
+      **scripted-diff**
+EOTEXT
+    );
+  }
+
+  public function getCommandHelp() {
+    return phutil_console_format(<<<EOTEXT
+      Supports: git
+      Check a scripted-diff commit matches the working directory content
+EOTEXT
+    );
+  }
+
+  public function requiresWorkingCopy() {
+    return true;
+  }
+
+  public function requiresRepositoryAPI() {
+    return true;
+  }
+
+  private function renderToConsole($result, $failureReason = '') {
+    $out = null;
+
+    switch($result) {
+      case self::RESULT_OKAY:
+        $out = phutil_console_format(
+          "**<bg:green> %s </bg>** %s\n",
+          pht('OKAY'),
+          pht('Scripted-diff check is successful'));
+        break;
+      case self::RESULT_ERRORS:
+        $out = phutil_console_format(
+          "**<bg:red> %s </bg>** %s\n",
+          pht('FAILED'),
+          pht($failureReason));
+        break;
+      default:
+        /* If there is nothing to display. */
+        break;
+    }
+
+    if ($out) {
+      PhutilConsole::getConsole()->writeOut($out);
+    }
+
+    return $result;
+  }
+
+  public function run() {
+    $root = $this->getWorkingCopy()->getProjectRoot();
+    $api = $this->getRepositoryAPI();
+
+    /* Git is the only source control system supported. */
+    if ($api->getSourceControlSystemName() !== 'git') {
+      return self::RESULT_SKIP;
+    }
+
+    $headCommit = $api->getHeadCommit();
+
+    $script = $this->getScriptFromCommitMessage(
+      $api->getCommitMessage($headCommit));
+
+    /* If this is not a scripted-diff, skip the check. */
+    if (!$script) {
+      return self::RESULT_SKIP;
+    }
+
+    $currentBranch = $api->getBranchName();
+    $baseCommit = $api->getBaseCommit();
+
+    /*
+     * Check that the working tree is clean.
+     *
+     * The getUncommittedStatus() method returns an array of flagged files for
+     * any of these file events: modified, added, deleted, untracked, conflict,
+     * missing, unstaged, uncommited.
+     *
+     * If the array is empty the working tree is clean.
+     * Note: until PHP 5.5, empty() only works if the parameter is a variable.
+     */
+    $uncommited = $api->getUncommittedStatus();
+    if (!empty($uncommited)) {
+      return $this->renderToConsole(self::RESULT_ERRORS,
+        'Scripted-diff check cannot run due to uncommited changes. '.
+        'Please commit or reset your changes.');
+    }
+
+    /* Checkout the base commit. */
+    $out = $api->execxLocal('checkout %s', $baseCommit);
+
+    $result = self::RESULT_OKAY;
+
+    /* Apply the script to the base commit from the root directory. */
+    $future = new ExecFuture($script);
+    $future->setCWD($root);
+    list($ret, , $stderr) = $future->resolve();
+
+    if ($ret != 0) {
+      $result = $this->renderToConsole(self::RESULT_ERRORS,
+        "Scripted-diff: the script returned an error ($ret): $stderr");
+    } else {
+      /*
+       * If the script ran successfully, compare the ouput working tree to the
+       * current commit state.
+       */
+      list($retRaw) = $api->execManualLocal(
+        '--no-pager diff --exit-code %s', $headCommit);
+
+      /*
+       * Lint the output, then redo the comparison.
+       * The final result should not depend on whether the code is formatted or
+       * not.
+       */
+      $lintWorkflow = $this->buildChildWorkflow('lint',
+        ['--apply-patches', '--output=none']);
+      if ($lintWorkflow->run() != 0) {
+        $result = $this->renderToConsole(self::RESULT_ERRORS,
+          'Error while linting the base commit. '.
+          'Fixes the issue then run `arc scripted-diff` again.');
+      } else {
+        list($retLinted) = $api->execManualLocal(
+          '--no-pager diff --exit-code %s', $headCommit);
+
+        if ($retRaw != 0 && $retLinted != 0) {
+          $result = $this->renderToConsole(self::RESULT_ERRORS,
+            'Scripted-diff: scripted output does not match the commit '.
+            'content.');
+        }
+      }
+    }
+
+    $api->execxLocal('reset --hard HEAD');
+    $api->execxLocal('checkout %s', $currentBranch);
+
+    if ($result == self::RESULT_OKAY) {
+      return $this->renderToConsole($result);
+    }
+
+    return $result;
+  }
+}