diff --git a/src/google/adk/models/interactions_utils.py b/src/google/adk/models/interactions_utils.py
index 97f4343bf2..bb890c40c5 100644
--- a/src/google/adk/models/interactions_utils.py
+++ b/src/google/adk/models/interactions_utils.py
@@ -135,11 +135,7 @@
 # google-genai release does not declare on its request model. That model
 # discards keys it has no field for while serializing, so these never reach the
 # API and sending them is indistinguishable from never setting them.
-_UNDECLARED_SAMPLING_PARAMS = (
-    'temperature',
-    'top_p',
-    'top_k',
-)
+_UNDECLARED_SAMPLING_PARAMS = ('top_k',)
 
 # Sampling knobs the interactions API itself rejects as unknown parameters.
 # No release of the client can carry these, so the caller has to stop setting
@@ -1334,6 +1330,10 @@ def build_generation_config(
     A dictionary containing generation configuration parameters.
   """
   generation_config: GenerationConfigParam = {}
+  if config.temperature is not None:
+    generation_config['temperature'] = config.temperature
+  if config.top_p is not None:
+    generation_config['top_p'] = config.top_p
   if config.max_output_tokens is not None:
     generation_config['max_output_tokens'] = config.max_output_tokens
   if config.stop_sequences:
diff --git a/tests/unittests/models/test_interactions_utils.py b/tests/unittests/models/test_interactions_utils.py
index adfefeed33..169265e0da 100644
--- a/tests/unittests/models/test_interactions_utils.py
+++ b/tests/unittests/models/test_interactions_utils.py
@@ -1346,6 +1346,8 @@ def test_all_parameters(self):
     )
     result = interactions_utils.build_generation_config(config)
     assert result == {
+        'temperature': 0.7,
+        'top_p': 0.9,
         'max_output_tokens': 100,
         'stop_sequences': ['END'],
         'seed': 7,
@@ -1358,7 +1360,7 @@ def test_partial_parameters(self):
         max_output_tokens=50,
     )
     result = interactions_utils.build_generation_config(config)
-    assert result == {'max_output_tokens': 50}
+    assert result == {'temperature': 0.5, 'max_output_tokens': 50}
 
   def test_empty_config(self):
     """Test building config with no parameters."""
@@ -1380,7 +1382,13 @@ def test_every_key_is_a_real_generation_config_field(self):
     )
     result = interactions_utils.build_generation_config(config)
     supported = set(typing.get_type_hints(interactions.GenerationConfigParam))
-    assert set(result) == {'max_output_tokens', 'stop_sequences', 'seed'}
+    assert set(result) == {
+        'temperature',
+        'top_p',
+        'max_output_tokens',
+        'stop_sequences',
+        'seed',
+    }
     assert set(result) <= supported
 
   def test_dropped_parameters_are_the_ones_the_request_cannot_carry(self):
@@ -1404,9 +1412,9 @@ def test_undeclared_parameters_point_at_the_client(self, caplog):
         r.getMessage() for r in caplog.records if r.levelno >= logging.WARNING
     ]
     assert len(warnings) == 1
-    assert 'temperature' in warnings[0]
-    assert 'top_p' in warnings[0]
     assert 'top_k' in warnings[0]
+    assert 'temperature' not in warnings[0]
+    assert 'top_p' not in warnings[0]
     assert 'google-genai' in warnings[0]
     assert 'use_interactions_api' not in warnings[0]
 
@@ -1431,7 +1439,7 @@ def test_unsupported_parameters_point_at_the_api(self, caplog):
 
   def test_the_two_causes_are_reported_separately(self, caplog):
     """Test that one cause is not folded into the other's remedy."""
-    config = types.GenerateContentConfig(temperature=0.7, presence_penalty=0.5)
+    config = types.GenerateContentConfig(top_k=40, presence_penalty=0.5)
 
     with caplog.at_level(
         logging.WARNING, logger=interactions_utils.logger.name
@@ -1443,12 +1451,12 @@ def test_the_two_causes_are_reported_separately(self, caplog):
     ]
     assert len(warnings) == 2
     client, api = sorted(warnings, key=lambda w: 'use_interactions_api' in w)
-    assert 'temperature' in client and 'presence_penalty' not in client
-    assert 'presence_penalty' in api and 'temperature' not in api
+    assert 'top_k' in client and 'presence_penalty' not in client
+    assert 'presence_penalty' in api and 'top_k' not in api
 
   def test_dropped_parameters_are_logged_once(self, caplog):
     """Test that a parameter is reported once, not on every model turn."""
-    config = types.GenerateContentConfig(temperature=0.7)
+    config = types.GenerateContentConfig(top_k=40)
 
     with caplog.at_level(
         logging.WARNING, logger=interactions_utils.logger.name