diff --git a/src/exdf/data_reduction/builtins.py b/src/exdf/data_reduction/builtins.py
index a9f3e8884f02d34d34b95bda87fa19f20739e971..965f40197df9b1fb39d6f1ff9774a616b7799119 100644
--- a/src/exdf/data_reduction/builtins.py
+++ b/src/exdf/data_reduction/builtins.py
@@ -199,7 +199,8 @@ class AgipdGain(ReductionMethod):
                                'explicit gain sources')
                 return
 
-            self.log.info(f'Found {domain}')
+            self.log.info(f'No detector specified, detected {domain} '
+                          f'automatically')
             agipd_sources = f'{domain}/DET/*CH0:xtdf'
 
         else:
@@ -214,6 +215,8 @@ class AgipdGain(ReductionMethod):
                         # Unfortunately HED uses a different domain for
                         # its AGIPD control devices, hardcode it here
                         # for convenience.
+                        # TODO: This could also be solved via a CalCat
+                        # query.
                         domain = domain.replace('_DET_', '_EXP_')
 
                     control_source = f'{domain}/MDL/FPGA_COMP'
diff --git a/src/exdf/data_reduction/writer.py b/src/exdf/data_reduction/writer.py
index e095fbda45b2555ac8da9a0567f5f1d4ae83bd73..33b6d94c42756eb89211093b1518339345147f0d 100644
--- a/src/exdf/data_reduction/writer.py
+++ b/src/exdf/data_reduction/writer.py
@@ -31,8 +31,8 @@ def apply_by_key(op_name):
         def op_handler(self):
             for source_glob, key_glob, *args in self._filter_ops(op_name):
                 for source in fnmatch.filter(self._sources, source_glob):
-                    keys = self._custom_keys.get(source,
-                                                set(self._data[source].keys()))
+                    keys = self._custom_keys.get(
+                        source, set(self._data[source].keys()))
 
                     for key in fnmatch.filter(keys, key_glob):
                         op_func(source, key, *args)
@@ -82,8 +82,8 @@ class ReduceWriter(SourceDataWriter):
         self._ops = sum(methods.values(), [])
 
         if not self._ops:
-            self.log.warning('Sum of reduction methods yielded no operations '
-                             'to apply')
+            self.log.warning('Sum of reduction methods yielded '
+                             'no operations to apply')
 
         self._sources = sorted(data.all_sources)
         self._touched_sources = set()
@@ -117,7 +117,6 @@ class ReduceWriter(SourceDataWriter):
                 'Source may not be affected by both select-entries and '
                 'select-xtdf operations')
 
-
         if self._rechunked_keys.keys() & self._compressed_keys.keys():
             raise ReduceMethodError('Key may not be affected by both '
                                     'compress-keys and rechunk-keys')