diff --git a/PKG-INFO b/PKG-INFO
index c0ac50f216d61f1ea7bbdde9081ef7716a80b854..ee50d594037bae70cb7aa580678385bba6d6bb3b 100644
--- a/PKG-INFO
+++ b/PKG-INFO
@@ -1,6 +1,6 @@
 Metadata-Version: 2.1
 Name: swh.model
-Version: 0.0.66
+Version: 0.0.67
 Summary: Software Heritage data model
 Home-page: https://forge.softwareheritage.org/diffusion/DMOD/
 Author: Software Heritage developers
diff --git a/swh.model.egg-info/PKG-INFO b/swh.model.egg-info/PKG-INFO
index c0ac50f216d61f1ea7bbdde9081ef7716a80b854..ee50d594037bae70cb7aa580678385bba6d6bb3b 100644
--- a/swh.model.egg-info/PKG-INFO
+++ b/swh.model.egg-info/PKG-INFO
@@ -1,6 +1,6 @@
 Metadata-Version: 2.1
 Name: swh.model
-Version: 0.0.66
+Version: 0.0.67
 Summary: Software Heritage data model
 Home-page: https://forge.softwareheritage.org/diffusion/DMOD/
 Author: Software Heritage developers
diff --git a/swh/model/cli.py b/swh/model/cli.py
index ae51d190c6423b1f9f963d791465c3ded81ecd5b..ad7e2f5fe7e77e583a346d426d18b3bf7a305a42 100644
--- a/swh/model/cli.py
+++ b/swh/model/cli.py
@@ -37,7 +37,7 @@ class PidParamType(click.ParamType):
             pids.parse_persistent_identifier(value)
             return value  # return as string, as we need just that
         except ValidationError as e:
-            self.fail("%s is not a valid PID. %s." % (value, e), param, ctx)
+            self.fail("%s is not a valid SWHID. %s." % (value, e), param, ctx)
 
 
 def pid_of_file(path):
@@ -155,20 +155,22 @@ def identify_object(obj_type, follow_symlinks, obj):
 @click.option(
     "--verify",
     "-v",
-    metavar="PID",
+    metavar="SWHID",
     type=PidParamType(),
     help="reference identifier to be compared with computed one",
 )
-@click.argument("objects", nargs=-1)
+@click.argument("objects", nargs=-1, required=True)
 def identify(obj_type, verify, show_filename, follow_symlinks, objects):
-    """Compute the Software Heritage persistent identifier (PID) for the given
+    """Compute the Software Heritage persistent identifier (SWHID) for the given
     source code object(s).
 
-    For more details about Software Heritage PIDs see:
+    For more details about SWHIDs see:
 
     \b
     https://docs.softwareheritage.org/devel/swh-model/persistent-identifiers.html
 
+    Tip: you can pass "-" to identify the content of standard input.
+
     \b
     Examples:
 
@@ -188,8 +190,6 @@ def identify(obj_type, verify, show_filename, follow_symlinks, objects):
       swh:1:snp:510aa88bdc517345d258c1fc2babcd0e1f905e93	helloworld.git
 
     """  # NoQA  # overlong lines in shell examples are fine
-    if not objects:
-        objects = ["-"]
 
     if verify and len(objects) != 1:
         raise click.BadParameter("verification requires a single object")
@@ -199,10 +199,10 @@ def identify(obj_type, verify, show_filename, follow_symlinks, objects):
     if verify:
         pid = next(results)[1]
         if verify == pid:
-            click.echo("PID match: %s" % pid)
+            click.echo("SWHID match: %s" % pid)
             sys.exit(0)
         else:
-            click.echo("PID mismatch: %s != %s" % (verify, pid))
+            click.echo("SWHID mismatch: %s != %s" % (verify, pid))
             sys.exit(1)
     else:
         for (obj, pid) in results:
diff --git a/swh/model/identifiers.py b/swh/model/identifiers.py
index dd3451346a7226226a7dceab3413bfa243a7cb37..4d25184bef6227b27ea8473d2b86f3703c5ec202 100644
--- a/swh/model/identifiers.py
+++ b/swh/model/identifiers.py
@@ -743,11 +743,7 @@ class PersistentId(_PersistentId):
 
 
 def persistent_identifier(object_type, object_id, scheme_version=1, metadata={}):
-    """Compute persistent identifier (stable over time) as per
-       documentation.
-
-    Documentation:
-        https://docs.softwareheritage.org/devel/swh-model/persistent-identifiers.html  # noqa
+    """Compute :ref:`SWHID <persistent-identifiers>` persistent identifiers.
 
     Args:
         object_type (str): object's type, either 'content', 'directory',
@@ -776,7 +772,7 @@ def persistent_identifier(object_type, object_id, scheme_version=1, metadata={})
 
 
 def parse_persistent_identifier(persistent_id):
-    """Parse swh's :ref:`persistent-identifiers` scheme.
+    """Parse :ref:`SWHID <persistent-identifiers>` persistent identifiers.
 
     Args:
         persistent_id (str): A persistent identifier
diff --git a/swh/model/tests/test_cli.py b/swh/model/tests/test_cli.py
index fac1d89d7b414b395d876ea0e57f7090ea197050..21eb8c5c6cd573635f65bd4f3f011e8037c62016 100644
--- a/swh/model/tests/test_cli.py
+++ b/swh/model/tests/test_cli.py
@@ -26,6 +26,10 @@ class TestIdentify(DataMixin, unittest.TestCase):
         self.assertEqual(result.exit_code, 0)
         self.assertEqual(result.output.split()[0], pid)
 
+    def test_no_args(self):
+        result = self.runner.invoke(cli.identify)
+        self.assertNotEqual(result.exit_code, 0)
+
     def test_content_id(self):
         """identify file content"""
         self.make_contents(self.tmpdir_name)
@@ -38,7 +42,7 @@ class TestIdentify(DataMixin, unittest.TestCase):
         """identify file content"""
         self.make_contents(self.tmpdir_name)
         for _, content in self.contents.items():
-            result = self.runner.invoke(cli.identify, input=content["data"])
+            result = self.runner.invoke(cli.identify, ["-"], input=content["data"])
             self.assertPidOK(result, "swh:1:cnt:" + hash_to_hex(content["sha1_git"]))
 
     def test_directory_id(self):
diff --git a/version.txt b/version.txt
index 13f286901ff637c38568784646672dfab3a33233..8ac5b0a6fb155c6bc6030ec75bcb80041d11ae2c 100644
--- a/version.txt
+++ b/version.txt
@@ -1 +1 @@
-v0.0.66-0-g401bc17
\ No newline at end of file
+v0.0.67-0-gd52549f
\ No newline at end of file