diff --git a/interfaces/cython/cantera/ck2yaml.py b/interfaces/cython/cantera/ck2yaml.py
index 9962771e3..8575eb2b4 100644
--- a/interfaces/cython/cantera/ck2yaml.py
+++ b/interfaces/cython/cantera/ck2yaml.py
@@ -44,6 +44,7 @@ import re
 import itertools
 import getopt
 import textwrap
+from email.utils import formatdate
 
 try:
     import ruamel_yaml as yaml
@@ -742,6 +743,7 @@ class Parser:
         self.reactions = []
         self.final_reaction_comment = ''
         self.headerLines = []
+        self.files = []  # input file names
 
     def warn(self, message):
         if self.warning_as_error:
@@ -1832,6 +1834,18 @@ class Parser:
             if desc.strip():
                 emitter.dump({'description': yaml.scalarstring.PreservedScalarString(desc)}, dest)
 
+            # Additional information regarding conversion
+            files = [os.path.basename(f) for f in self.files]
+            metadata = BlockMap([
+                ('generator', 'ck2yaml'),
+                ('input-files', FlowList(files)),
+                ('cantera-version', '2.5.0a2'),
+                ('date', formatdate(localtime=True)),
+            ])
+            if desc.strip():
+                metadata.yaml_set_comment_before_after_key('generator', before='\n')
+            emitter.dump(metadata, dest)
+
             units = FlowMap([('length', 'cm'), ('time', 's')])
             units['quantity'] = self.output_quantity_units
             units['activation-energy'] = self.output_energy_units
diff --git a/interfaces/cython/cantera/cti2yaml.py b/interfaces/cython/cantera/cti2yaml.py
index 0dab16292..a3760eecd 100644
--- a/interfaces/cython/cantera/cti2yaml.py
+++ b/interfaces/cython/cantera/cti2yaml.py
@@ -19,6 +19,7 @@ import re
 import pathlib
 from collections import OrderedDict
 import numpy as np
+from email.utils import formatdate
 
 try:
     import ruamel_yaml as yaml
@@ -1597,9 +1598,15 @@ def convert(filename=None, output_name=None, text=None):
             emitter.register_class(cls)
 
     with open(output_name, 'w') as dest:
-        outputStarted = False
-
-        # todo: header comment
+        # information regarding conversion
+        metadata = BlockMap([
+            ('generator', 'cti2yaml'),
+            ('cantera-version', '2.5.0a2'),
+            ('date', formatdate(localtime=True)),
+        ])
+        if filename is not None:
+            metadata['input-files'] = FlowList([base])
+        emitter.dump(metadata, dest)
 
         out_units = FlowMap([])
         if _umass != 'kg':
@@ -1619,36 +1626,28 @@ def convert(filename=None, output_name=None, text=None):
 
         if out_units:
             units_map = BlockMap([('units', out_units)])
+            units_map.yaml_set_comment_before_after_key('units', before='\n')
             emitter.dump(units_map, dest)
-            outputStarted = True
 
         if _elements:
             elements_map = BlockMap([('elements', _elements)])
-            if outputStarted:
-                elements_map.yaml_set_comment_before_after_key('elements', before='\n')
-            outputStarted = True
+            elements_map.yaml_set_comment_before_after_key('elements', before='\n')
             emitter.dump(elements_map, dest)
 
         if _phases:
             phases_map = BlockMap([('phases', _phases)])
-            if outputStarted:
-                phases_map.yaml_set_comment_before_after_key('phases', before='\n')
-            outputStarted = True
+            phases_map.yaml_set_comment_before_after_key('phases', before='\n')
             emitter.dump(phases_map, dest)
 
         if _species:
             species_map = BlockMap([('species', _species)])
-            if outputStarted:
-                species_map.yaml_set_comment_before_after_key('species', before='\n')
-            outputStarted = True
+            species_map.yaml_set_comment_before_after_key('species', before='\n')
             emitter.dump(species_map, dest)
 
         for name, reactions in _reactions.items():
             if reactions:
                 reactions_map = BlockMap([(name, reactions)])
-                if outputStarted:
-                    reactions_map.yaml_set_comment_before_after_key(name, before='\n')
-                outputStarted = True
+                reactions_map.yaml_set_comment_before_after_key(name, before='\n')
                 emitter.dump(reactions_map, dest)