diff --git a/tests/e2e/coverage_registry/logging.yaml b/tests/e2e/coverage_registry/logging.yaml
index 65ab8f0096f..c4b26387c13 100644
--- a/tests/e2e/coverage_registry/logging.yaml
+++ b/tests/e2e/coverage_registry/logging.yaml
@@ -8,7 +8,7 @@
 - {id: logging.datadog.success.exports_metric, module: logging, tier: P0, event: success, assertions: [exports_metric], exercised_on: [chat_completions, messages, embeddings], source: "integrations/datadog/datadog.py", rationale: "Powers dashboards/alerts; cardinality regressions common"}
 - {id: logging.datadog.failure.exports_metric, module: logging, tier: P0, event: failure, assertions: [exports_metric], exercised_on: [chat_completions], source: "integrations/datadog/datadog.py", rationale: "Failure metrics for alerting/SLO"}
 - {id: logging.prometheus.success.exports_metric, module: logging, tier: P0, event: success, assertions: [exports_metric], exercised_on: [chat_completions, messages, embeddings], source: "integrations/prometheus.py", rationale: "Standard OSS metrics; per-key cardinality (existing e2e)"}
-- {id: logging.otel.success.exports_metric, module: logging, tier: P0, event: success, assertions: [exports_metric], exercised_on: [chat_completions, messages, embeddings], source: "integrations/otel/logger.py", rationale: "OTEL spans on every call path"}
+- {id: logging.otel.success.exports_metric, module: logging, tier: P0, event: success, assertions: [exports_metric], exercised_on: [chat_completions, messages, responses, embeddings], source: "integrations/otel/logger.py", rationale: "OTEL spans on every call path"}
 - {id: logging.otel.failure.exports_metric, module: logging, tier: P0, event: failure, assertions: [exports_metric], exercised_on: [chat_completions, messages], source: "integrations/otel/logger.py", rationale: "Error spans for observability continuity"}
 - {id: logging.braintrust.success.logs_spend, module: logging, tier: P1, event: success, assertions: [logs_spend], exercised_on: [chat_completions, messages], source: "integrations/braintrust_logging.py", rationale: "Evals platform spend"}
 - {id: logging.langsmith.success.logs_spend, module: logging, tier: P1, event: success, assertions: [logs_spend], exercised_on: [chat_completions, messages], source: "integrations/langsmith.py", rationale: "LangChain ecosystem"}
diff --git a/tests/e2e/e2e_config.py b/tests/e2e/e2e_config.py
index 6bfec2b514e..6e6c30709de 100644
--- a/tests/e2e/e2e_config.py
+++ b/tests/e2e/e2e_config.py
@@ -25,6 +25,7 @@
 UI_PASSWORD = os.environ.get("E2E_UI_PASSWORD", MASTER_KEY)
 
 CHEAP_ANTHROPIC_MODEL = os.environ.get("E2E_CHEAP_ANTHROPIC_MODEL", "claude-haiku-4-5")
+CHEAP_OPENAI_MODEL = os.environ.get("E2E_CHEAP_OPENAI_MODEL", "gpt-5.5")
 
 # Jaeger query API of the compose stack's OTEL trace destination (the `jaeger`
 # service in docker-compose.yml maps it to host 16686). Trace-completeness tests
diff --git a/tests/e2e/logging/logging_client.py b/tests/e2e/logging/logging_client.py
index 6071e657bd3..bffdf71ed80 100644
--- a/tests/e2e/logging/logging_client.py
+++ b/tests/e2e/logging/logging_client.py
@@ -35,6 +35,7 @@
     unwrap,
 )
 from models import (
+    AnthropicMessagesBody,
     ChatBody,
     ChatMessage,
     ChatResponse,
@@ -75,6 +76,14 @@
 )
 
 
+class ResponsesRequestBody(BaseModel):
+    """OpenAI Responses API /v1/responses request (non-streaming)."""
+
+    model: str
+    input: str
+    max_output_tokens: int
+
+
 class TeamCallbackBody(BaseModel):
     callback_name: Literal["langfuse_otel", "langfuse", "langsmith", "gcs"]
     callback_type: Literal["success", "failure", "success_and_failure"]
@@ -455,6 +464,32 @@ def chat_raw(
             json=body,
         )
 
+    def messages_raw(self, key: str, model: str, text: str, *, max_tokens: int = 16) -> StreamingResponse:
+        """Non-streaming POST /v1/messages (Anthropic-native body): raw outcome
+        judged by status/body/headers, for tests that need x-litellm-call-id."""
+        return self.gateway.transport.send(
+            "/v1/messages",
+            headers=self.gateway.transport.bearer(key),
+            json=AnthropicMessagesBody(
+                model=model,
+                max_tokens=max_tokens,
+                messages=[ChatMessage(role="user", content=text)],
+            ),
+        )
+
+    def responses_raw(
+        self, key: str, model: str, text: str, *, max_output_tokens: int = 64
+    ) -> StreamingResponse:
+        """Non-streaming POST /v1/responses (OpenAI Responses API): raw outcome
+        judged by status/body/headers, for tests that need x-litellm-call-id.
+        max_output_tokens caps reasoning-model output cost; a capped response is
+        still a 200 and still exports the trace."""
+        return self.gateway.transport.send(
+            "/v1/responses",
+            headers=self.gateway.transport.bearer(key),
+            json=ResponsesRequestBody(model=model, input=text, max_output_tokens=max_output_tokens),
+        )
+
     def scrape_metrics(self) -> str:
         return self.gateway.probe("/metrics", params=NoBody()).body
 
diff --git a/tests/e2e/logging/test_otel_trace_e2e.py b/tests/e2e/logging/test_otel_trace_e2e.py
index d445da3dff0..90887ea5510 100644
--- a/tests/e2e/logging/test_otel_trace_e2e.py
+++ b/tests/e2e/logging/test_otel_trace_e2e.py
@@ -23,7 +23,7 @@
 import pytest
 from pydantic import BaseModel, ConfigDict
 
-from e2e_config import CHEAP_ANTHROPIC_MODEL, unique_marker
+from e2e_config import CHEAP_ANTHROPIC_MODEL, CHEAP_OPENAI_MODEL, unique_marker
 from e2e_http import NoBody, StreamingResponse, require_successful_call
 from lifecycle import ResourceManager
 from logging_client import LoggingClient
@@ -151,7 +151,7 @@ def _settled_names(*, route: str, genai_span: str) -> set[str]:
 
 
 class TestOtelTraceCompleteness:
-    @pytest.mark.covers("logging.otel.success.exports_metric")
+    @pytest.mark.covers("logging.otel.success.exports_metric", exercised_on=["chat_completions"])
     def test_chat_completions_exports_complete_trace(
         self, client: LoggingClient, otel_reader: OtelReader, resources: ResourceManager
     ) -> None:
@@ -189,3 +189,71 @@ def test_chat_completions_exports_complete_trace(
             settled_prefixes={DB_SPAN_PREFIX},
         )
         _assert_complete_trace(hits, route=route, genai_span=f"chat {MODEL}")
+
+    @pytest.mark.covers("logging.otel.success.exports_metric", exercised_on=["messages"])
+    def test_messages_exports_complete_trace(
+        self, client: LoggingClient, otel_reader: OtelReader, resources: ResourceManager
+    ) -> None:
+        """This test verifies that one successful non-streaming /v1/messages request
+        produces exactly one complete OTEL trace.
+
+        The trace must have a single root span named "POST /v1/messages". The
+        authentication, database, cost-writing, and model-call spans must all belong to
+        the same trace and have valid parent relationships leading back to that root.
+
+        The model-call span is expected to be named "chat <model>". The test fails if
+        the request is split across multiple traces, if any span references a missing
+        parent, or if the model-call span cannot be connected back to the root."""
+        route = "/v1/messages"
+        _assert_otel_destination_configured(client)
+
+        key = client.key_with_alias(f"otel-trace-messages-{unique_marker()}", models=[MODEL])
+        resources.defer(lambda: client.delete_key(key))
+
+        marker = unique_marker()
+        outcome = _first_ok(
+            client, lambda: client.messages_raw(key, MODEL, f"reply with one word {marker}", max_tokens=16)
+        )
+        assert outcome.call_id is not None, "success response must carry x-litellm-call-id"
+
+        hits = otel_reader.poll_traces_for_call(
+            call_id=outcome.call_id,
+            settled_names=_settled_names(route=route, genai_span=f"chat {MODEL}"),
+            settled_prefixes={DB_SPAN_PREFIX},
+        )
+        _assert_complete_trace(hits, route=route, genai_span=f"chat {MODEL}")
+
+    @pytest.mark.covers("logging.otel.success.exports_metric", exercised_on=["responses"])
+    def test_responses_exports_complete_trace(
+        self, client: LoggingClient, otel_reader: OtelReader, resources: ResourceManager
+    ) -> None:
+        """This test verifies that one successful non-streaming /v1/responses request
+        produces exactly one complete OTEL trace.
+
+        The trace must have a single root span named "POST /v1/responses". The
+        authentication, database, cost-writing, and model-call spans must all belong to
+        the same trace and have valid parent relationships leading back to that root.
+
+        The model-call span is expected to be named "chat <model>". The test fails if
+        the request is split across multiple traces, if any span references a missing
+        parent, or if the model-call span cannot be connected back to the root."""
+        route = "/v1/responses"
+        _assert_otel_destination_configured(client)
+
+        key = client.key_with_alias(f"otel-trace-responses-{unique_marker()}", models=[CHEAP_OPENAI_MODEL])
+        resources.defer(lambda: client.delete_key(key))
+
+        marker = unique_marker()
+        outcome = _first_ok(
+            client,
+            lambda: client.responses_raw(key, CHEAP_OPENAI_MODEL, f"reply with one word {marker}"),
+        )
+        assert outcome.call_id is not None, "success response must carry x-litellm-call-id"
+
+        genai_span = f"chat {CHEAP_OPENAI_MODEL}"
+        hits = otel_reader.poll_traces_for_call(
+            call_id=outcome.call_id,
+            settled_names=_settled_names(route=route, genai_span=genai_span),
+            settled_prefixes={DB_SPAN_PREFIX},
+        )
+        _assert_complete_trace(hits, route=route, genai_span=genai_span)