diff --git a/litellm/proxy/litellm_pre_call_utils.py b/litellm/proxy/litellm_pre_call_utils.py
index 0a80f47ce59..8397a904190 100644
--- a/litellm/proxy/litellm_pre_call_utils.py
+++ b/litellm/proxy/litellm_pre_call_utils.py
@@ -150,8 +150,13 @@ def _session_id_from_baggage(baggage: str) -> str | None:
     return None
 
 
-def _client_steered_trace_field(metadata: object, field: str) -> bool:
-    return isinstance(metadata, Mapping) and bool(cast(Mapping[str, object], metadata).get(field))
+def _caller_set_trace_field(data: Mapping[str, object], metadata_variable_name: str, field: str) -> bool:
+    promoted: Final = metadata_variable_name == "litellm_metadata" and field in LITELLM_TRACE_CONTROL_METADATA_FIELDS
+    sources: Final = (metadata_variable_name, "metadata") if promoted else (metadata_variable_name,)
+    return any(
+        isinstance(container := data.get(name), Mapping) and bool(cast(Mapping[str, object], container).get(field))
+        for name in sources
+    )
 
 
 def _stampable_key_hash(user_api_key_dict: UserAPIKeyAuth) -> str | None:
@@ -829,7 +834,7 @@ def apply_missing_session_id_policy(
         ):
             metadata["session_id"] = body_session_id
         return
-    if data.get("litellm_session_id") or metadata.get("session_id"):
+    if data.get("litellm_session_id") or _caller_set_trace_field(data, _metadata_variable_name, "session_id"):
         return
     match policy:
         case "generate":
@@ -1584,8 +1589,8 @@ class LiteLLMProxyRequestSetup:
         # correlate with litellm's own logs instead of generating an unrelated
         # trace_id.
         normalized_headers: Final = MappingProxyType({k.lower(): v for k, v in headers.items() if isinstance(k, str)})
-        if "litellm_trace_id" not in data and not _client_steered_trace_field(
-            cast(object, data.get(_metadata_variable_name)), "trace_id"
+        if "litellm_trace_id" not in data and not _caller_set_trace_field(
+            cast(Mapping[str, object], data), _metadata_variable_name, "trace_id"
         ):
             traceparent: Final = normalized_headers.get("traceparent")
             if isinstance(traceparent, str):
@@ -1596,8 +1601,8 @@ class LiteLLMProxyRequestSetup:
                     verbose_proxy_logger.debug(
                         "Extracted trace_id from W3C traceparent header: %s", trace_id_from_traceparent
                     )
-        if "litellm_session_id" not in data and not _client_steered_trace_field(
-            cast(object, data.get(_metadata_variable_name)), "session_id"
+        if "litellm_session_id" not in data and not _caller_set_trace_field(
+            cast(Mapping[str, object], data), _metadata_variable_name, "session_id"
         ):
             baggage: Final = normalized_headers.get("baggage")
             if isinstance(baggage, str):
diff --git a/tests/test_litellm/proxy/test_litellm_pre_call_utils.py b/tests/test_litellm/proxy/test_litellm_pre_call_utils.py
index bbd8992928d..f99eb5c9b30 100644
--- a/tests/test_litellm/proxy/test_litellm_pre_call_utils.py
+++ b/tests/test_litellm/proxy/test_litellm_pre_call_utils.py
@@ -3704,13 +3704,18 @@ def test_add_litellm_metadata_from_request_headers_empty_body_session_id_falls_b
     assert data["metadata"]["session_id"] == "baggage-session-42"
 
 
-def test_add_litellm_metadata_from_request_headers_provider_metadata_does_not_block_baggage():
-    headers = {"baggage": "session.id=baggage-session-42"}
-    data = {"metadata": {"session_id": "provider-facing-value"}, "litellm_metadata": {}}
+@pytest.mark.parametrize("field", ["trace_id", "session_id"])
+def test_add_litellm_metadata_from_request_headers_promoted_metadata_beats_headers(field: str):
+    headers = {
+        "traceparent": "00-4bf92f3577b34da6a3ce929d0e0e4736-00f067aa0ba902b7-01",
+        "baggage": "session.id=baggage-session-42",
+    }
+    data = {"metadata": {field: "caller-chosen"}, "litellm_metadata": {}}
     LiteLLMProxyRequestSetup.add_litellm_metadata_from_request_headers(
         headers=headers, data=data, _metadata_variable_name="litellm_metadata"
     )
-    assert data["litellm_session_id"] == "baggage-session-42"
+    assert field not in data["litellm_metadata"]
+    assert f"litellm_{field}" not in data
 
 
 def _otel_span_with_trace_id(trace_id: int) -> NonRecordingSpan:
@@ -8200,7 +8205,7 @@ async def test_missing_session_id_omit_keeps_client_supplied_session_id():
     ("path", "client_body"),
     [
         ("/v1/chat/completions", {"model": "gpt-4o", "messages": [], "metadata": {"session_id": ""}}),
-        ("/v1/responses", {"model": "gpt-4o", "input": "hi", "metadata": {"session_id": "provider-facing"}}),
+        ("/v1/responses", {"model": "gpt-4o", "input": "hi"}),
     ],
 )
 async def test_missing_session_id_reject_accepts_baggage_session_id(path: str, client_body: dict[str, object]):
@@ -8218,6 +8223,28 @@ async def test_missing_session_id_reject_accepts_baggage_session_id(path: str, c
     assert updated["litellm_session_id"] == "baggage-session-42"
 
 
+@pytest.mark.asyncio
+@pytest.mark.parametrize("path", ["/v1/responses", "/v1/messages"])
+@pytest.mark.parametrize("policy", [None, "reject", "generate"])
+async def test_promoted_caller_trace_ids_beat_traceparent_and_baggage(path: str, policy: str | None):
+    request = _request_for(path)
+    request.headers = {
+        "traceparent": "00-4bf92f3577b34da6a3ce929d0e0e4736-00f067aa0ba902b7-01",
+        "baggage": "session.id=baggage-session-42",
+    }
+
+    updated = await add_litellm_data_to_request(
+        data={"model": "gpt-4o", "metadata": {"trace_id": "caller-trace", "session_id": "caller-session"}},
+        request=request,
+        user_api_key_dict=UserAPIKeyAuth(api_key="hashed-key"),
+        proxy_config=MagicMock(),
+        general_settings={"missing_session_id": policy} if policy else {},
+    )
+
+    assert updated["litellm_metadata"]["trace_id"] == "caller-trace"
+    assert updated["litellm_metadata"]["session_id"] == "caller-session"
+
+
 @pytest.mark.asyncio
 @pytest.mark.parametrize(
     "client_body",