diff --git a/pydir/build-pnacl-ir.py b/pydir/build-pnacl-ir.py
index 608c574..5c4c9e8 100755
--- a/pydir/build-pnacl-ir.py
+++ b/pydir/build-pnacl-ir.py
@@ -11,7 +11,7 @@
     argparser.add_argument('cfile', nargs='+', type=str,
         help='C file(s) to convert')
     argparser.add_argument('--dir', nargs='?', type=str, default='.',
-                           help='Output directory')
+                           help='Output directory. Default "%(default)s".')
     argparser.add_argument('--disable-verify', action='store_true')
     args = argparser.parse_args()
 
diff --git a/pydir/crosstest.py b/pydir/crosstest.py
index 54010c5..b4146c1 100755
--- a/pydir/crosstest.py
+++ b/pydir/crosstest.py
@@ -37,15 +37,18 @@
     argparser.add_argument('--target', required=False, default='x8632',
                            choices=arch_map.keys(),
                            metavar='TARGET',
-                           help='Translation target architecture')
+                           help='Translation target architecture.' +
+                                ' Default %(default)s.')
     argparser.add_argument('-O', required=False, default='2', dest='optlevel',
                            choices=['m1', '-1', '0', '1', '2'],
                            metavar='OPTLEVEL',
                            help='Optimization level ' +
-                                '(m1 and -1 are equivalent)')
+                                '(m1 and -1 are equivalent).' +
+                                ' Default %(default)s.')
     argparser.add_argument('--mattr',  required=False, default='sse2',
                            dest='attr', choices=['sse2', 'sse4.1'],
-                           metavar='ATTRIBUTE', help='Target attribute')
+                           metavar='ATTRIBUTE',
+                           help='Target attribute. Default %(default)s.')
     argparser.add_argument('--prefix', required=True,
                            metavar='SZ_PREFIX',
                            help='String prepended to Subzero symbol names')
@@ -54,12 +57,14 @@
                            help='Executable to produce')
     argparser.add_argument('--dir', required=False, default='.',
                            metavar='OUTPUT_DIR',
-                           help='Output directory for all files')
+                           help='Output directory for all files.' +
+                                ' Default "%(default)s".')
     argparser.add_argument('--crosstest-bitcode', required=False,
                            default=1, type=int,
                            help='Compile non-subzero crosstest object file ' +
                            'from the same bitcode as the subzero object. ' +
-                           'If 0, then compile it straight from source.')
+                           'If 0, then compile it straight from source.' +
+                           ' Default %(default)d.')
     args = argparser.parse_args()
 
     nacl_root = FindBaseNaCl()
diff --git a/pydir/szbuild.py b/pydir/szbuild.py
index 8adc683..dd94bda 100755
--- a/pydir/szbuild.py
+++ b/pydir/szbuild.py
@@ -108,11 +108,12 @@
                                 '(regex or line range)')
     argparser.add_argument('--output', '-o', default='a.out', dest='output',
                            action='store',
-                           help='Output executable (default a.out)')
+                           help='Output executable. Default %(default)s.')
     argparser.add_argument('-O', default='2', dest='optlevel',
                            choices=['m1', '-1', '0', '1', '2'],
                            help='Optimization level ' +
-                                '(m1 and -1 are equivalent)')
+                                '(m1 and -1 are equivalent).' +
+                                ' Default %(default)s.')
     argparser.add_argument('--verbose', '-v', dest='verbose',
                            action='store_true',
                            help='Display some extra debugging output')