From cf5a22a9d566eebf75e92b064070b3ac712cd1be Mon Sep 17 00:00:00 2001
From: Asaf Vertman <avertman@gmail.com>
Date: Thu, 16 Apr 2026 10:25:18 +0300
Subject: [PATCH] fix(langfuse_otel): tighten responses observation payload

---
 .../langfuse/langfuse_otel_attributes.py      | 11 +++++++--
 .../integrations/test_langfuse_otel.py        | 23 +++++++++++++++++++
 2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/litellm/integrations/langfuse/langfuse_otel_attributes.py b/litellm/integrations/langfuse/langfuse_otel_attributes.py
index a8b1de17973..15c8525f75e 100644
--- a/litellm/integrations/langfuse/langfuse_otel_attributes.py
+++ b/litellm/integrations/langfuse/langfuse_otel_attributes.py
@@ -15,7 +15,10 @@ from litellm.integrations.opentelemetry_utils.base_otel_llm_obs_attributes impor
     safe_set_attribute,
 )
 from litellm.litellm_core_utils.safe_json_dumps import safe_dumps
-from litellm.types.llms.openai import HttpxBinaryResponseContent, ResponsesAPIResponse
+from litellm.types.llms.openai import (
+    HttpxBinaryResponseContent,
+    ResponsesAPIResponse,
+)
 from litellm.types.utils import (
     EmbeddingResponse,
     ImageResponse,
@@ -102,18 +105,22 @@ def get_langfuse_observation_input_by_type(
     response_input = kwargs.get("input")
     if response_input is not None:
         prompt: dict[str, Any] = {"input": response_input}
+        # Keep the Responses observation focused on request fields that affect
+        # model context, tool behavior, or response shape.
         for key in (
             "instructions",
-            "functions",
             "tools",
             "tool_choice",
             "reasoning",
             "max_output_tokens",
+            "max_tool_calls",
             "text",
             "parallel_tool_calls",
             "truncation",
             "temperature",
             "top_p",
+            "previous_response_id",
+            "prompt",
         ):
             value = optional_params.get(key)
             if value is not None:
diff --git a/tests/test_litellm/integrations/test_langfuse_otel.py b/tests/test_litellm/integrations/test_langfuse_otel.py
index 661fa1c6155..8c487085c4d 100644
--- a/tests/test_litellm/integrations/test_langfuse_otel.py
+++ b/tests/test_litellm/integrations/test_langfuse_otel.py
@@ -499,6 +499,14 @@ class TestLangfuseOtelResponsesAPI:
                 ],
                 "tool_choice": "auto",
                 "reasoning": {"effort": "low"},
+                "previous_response_id": "resp_prev_123",
+                "prompt": {
+                    "id": "pmpt_123",
+                    "variables": {"tenant": "acme"},
+                },
+                "max_tool_calls": 3,
+                "functions": [{"name": "legacy_chat_only"}],
+                "metadata": {"request_id": "req_123"},
                 "stream": False,
             },
             "litellm_params": {"custom_llm_provider": "openai", "metadata": {}},
@@ -510,6 +518,12 @@ class TestLangfuseOtelResponsesAPI:
                     "tools": [{"type": "function", "name": "list_applications"}],
                     "tool_choice": "auto",
                     "reasoning": {"effort": "low"},
+                    "previous_response_id": "resp_prev_123",
+                    "prompt": {
+                        "id": "pmpt_123",
+                        "variables": {"tenant": "acme"},
+                    },
+                    "max_tool_calls": 3,
                     "stream": False,
                 },
             },
@@ -544,6 +558,15 @@ class TestLangfuseOtelResponsesAPI:
         assert observation_input["tool_choice"] == "auto"
         assert observation_input["reasoning"] == {"effort": "low"}
         assert observation_input["tools"][0]["name"] == "list_applications"
+        assert observation_input["previous_response_id"] == "resp_prev_123"
+        assert observation_input["prompt"] == {
+            "id": "pmpt_123",
+            "variables": {"tenant": "acme"},
+        }
+        assert observation_input["max_tool_calls"] == 3
+        assert "functions" not in observation_input
+        assert "metadata" not in observation_input
+        assert "stream" not in observation_input
         assert (
             "show me connected applications with high risk"
             in actual_attributes["langfuse.observation.input"]