diff --git a/doc/api.rst b/doc/api.rst
index ded5051ca..9077b539a 100644
--- a/doc/api.rst
+++ b/doc/api.rst
@@ -109,10 +109,12 @@ Operations and Status
 .. autoclass:: flow.project.FlowOperation
     :show-inheritance:
     :members:
+    :special-members: __call__
 
 .. autoclass:: flow.project.FlowCmdOperation
     :show-inheritance:
     :members:
+    :special-members: __call__
 
 .. autoclass:: flow.project.JobOperation
     :members:
@@ -120,6 +122,20 @@ Operations and Status
 .. autoclass:: flow.render_status.Renderer
     :members: generate_terminal_output, generate_html_output, render
 
+Labels
+------
+
+.. autoclass:: flow.label
+    :members:
+    :special-members: __call__
+
+.. autoclass:: flow.staticlabel
+    :members:
+    :special-members: __call__
+
+.. autoclass:: flow.classlabel
+    :members:
+    :special-members: __call__
 
 @flow.cmd
 ---------
@@ -135,6 +151,8 @@ Operations and Status
 ----------------
 
 .. autoclass:: directives
+    :members:
+    :special-members: __call__
 
 flow.run()
 ----------
@@ -157,6 +175,10 @@ The FlowGroup
 .. autoclass:: flow.project.FlowGroup
     :members:
 
+.. autoclass:: flow.project.FlowGroupEntry
+    :members:
+    :special-members: __call__
+
 Aggregation
 -----------
 
@@ -164,6 +186,7 @@ Aggregation
 
 .. autoclass:: flow.aggregates.aggregator
     :members:
+    :special-members: __call__
 
 .. autofunction:: flow.aggregates.get_aggregate_id
 
diff --git a/flow/project.py b/flow/project.py
index 590062992..17e833f40 100644
--- a/flow/project.py
+++ b/flow/project.py
@@ -682,6 +682,7 @@ def __str__(self):
         return f"{type(self).__name__}(cmd='{self._cmd}')"
 
     def __call__(self, *jobs, **kwargs):
+        """Return the command formatted with the supplied job(s)."""
         job = kwargs.pop("job", None)
         if kwargs:
             raise ValueError(f"Invalid keyword arguments: {', '.join(kwargs)}")
@@ -734,7 +735,7 @@ def __call__(self, *jobs):
 
         Parameters
         ----------
-        \*jobs : One or more instances of :class:`.Job`.
+        \*jobs : One or more instances of :class:`~signac.contrib.job.Job`.
             The jobs passed to the operation.
 
         Returns