From 197d7e4fa92f41759c6c8eb6a69bbae02e49afb3 Mon Sep 17 00:00:00 2001
From: Ambuj Upadhyay <34904987+lets-order-some-fries@users.noreply.github.com>
Date: Sat, 15 Aug 2026 00:13:55 +0530
Subject: [PATCH] fix: tolerate RecursionError when decoding tool-call
 arguments

json.loads raises RecursionError (not JSONDecodeError) on deeply nested
input, which propagated and dropped the affected span. Fall back to the
raw string like any other undecodable payload.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
---
 litellm/integrations/datadog/datadog_llm_obs.py       |  2 +-
 .../datadog/test_datadog_llm_obs_message_schema.py    | 11 +++++++++++
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/litellm/integrations/datadog/datadog_llm_obs.py b/litellm/integrations/datadog/datadog_llm_obs.py
index 664a0c75f80..8a85cca2254 100644
--- a/litellm/integrations/datadog/datadog_llm_obs.py
+++ b/litellm/integrations/datadog/datadog_llm_obs.py
@@ -57,7 +57,7 @@ def _parse_tool_call_arguments(raw: object) -> object:
         return raw
     try:
         return json.loads(raw)
-    except json.JSONDecodeError:
+    except (RecursionError, json.JSONDecodeError):
         return raw
 
 
diff --git a/tests/test_litellm/integrations/datadog/test_datadog_llm_obs_message_schema.py b/tests/test_litellm/integrations/datadog/test_datadog_llm_obs_message_schema.py
index 0661a79687d..bd91ad8a8fe 100644
--- a/tests/test_litellm/integrations/datadog/test_datadog_llm_obs_message_schema.py
+++ b/tests/test_litellm/integrations/datadog/test_datadog_llm_obs_message_schema.py
@@ -366,3 +366,14 @@ class TestDataDogLLMObsCacheTokenMetrics:
             assert "cache_write_input_tokens" not in metrics
             assert "non_cached_input_tokens" not in metrics
             assert metrics["input_tokens"] == 20.0
+
+
+def test_parse_tool_call_arguments_survives_deeply_nested_json():
+    """A hostile/degenerate arguments string must fall back to the raw
+    string, not raise RecursionError and drop the span."""
+    from litellm.integrations.datadog.datadog_llm_obs import (
+        _parse_tool_call_arguments,
+    )
+
+    hostile = "[" * 50000
+    assert _parse_tool_call_arguments(hostile) == hostile