From e406a1759968e81649dbc9ad331b18bc804df908 Mon Sep 17 00:00:00 2001
From: Sylvester Kaczmarek
 <16242628+sylvesterkaczmarek@users.noreply.github.com>
Date: Mon, 17 Aug 2026 21:59:21 +0100
Subject: [PATCH 1/2] fix(tracing): detach serialized trace metadata

---
 src/agents/tracing/traces.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/agents/tracing/traces.py b/src/agents/tracing/traces.py
index a703acf317..adb7ac932a 100644
--- a/src/agents/tracing/traces.py
+++ b/src/agents/tracing/traces.py
@@ -2,6 +2,7 @@
 
 import abc
 import contextvars
+import copy
 import hashlib
 import threading
 from collections import OrderedDict
@@ -178,7 +179,7 @@ def to_json(self, *, include_tracing_api_key: bool = False) -> dict[str, Any] |
         exported = self.export()
         if exported is None:
             return None
-        payload = dict(exported)
+        payload = copy.deepcopy(exported)
         if include_tracing_api_key and self.tracing_api_key:
             payload["tracing_api_key"] = self.tracing_api_key
         return payload

From 53acf0a0bf46985d16625484eed273be95167f31 Mon Sep 17 00:00:00 2001
From: Sylvester Kaczmarek
 <16242628+sylvesterkaczmarek@users.noreply.github.com>
Date: Mon, 17 Aug 2026 21:59:35 +0100
Subject: [PATCH 2/2] test(tracing): cover detached trace JSON metadata

---
 tests/test_trace_json_isolation.py | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)
 create mode 100644 tests/test_trace_json_isolation.py

diff --git a/tests/test_trace_json_isolation.py b/tests/test_trace_json_isolation.py
new file mode 100644
index 0000000000..07599d4852
--- /dev/null
+++ b/tests/test_trace_json_isolation.py
@@ -0,0 +1,20 @@
+from __future__ import annotations
+
+from agents.tracing.provider import SynchronousMultiTracingProcessor
+from agents.tracing.traces import TraceImpl
+
+
+def test_trace_to_json_detaches_nested_metadata() -> None:
+    trace = TraceImpl(
+        name="workflow",
+        trace_id="trace_test",
+        group_id=None,
+        metadata={"nested": {"value": "original"}},
+        processor=SynchronousMultiTracingProcessor(),
+    )
+
+    payload = trace.to_json()
+    assert payload is not None
+    payload["metadata"]["nested"]["value"] = "changed"
+
+    assert trace.metadata == {"nested": {"value": "original"}}