From 8e8096b82038eda5f9c7ebd2424f75a9d210ce36 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E7=94=B5=E5=A4=A7=E8=80=81baby?= <3231811510@qq.com>
Date: Mon, 9 Nov 2026 11:56:00 +0800
Subject: [PATCH] FIX: Deep-copy seed metadata when converting SeedGroup
 prompts to messages

---
 pyrit/models/seeds/seed_group.py     |  3 ++-
 tests/unit/models/test_seed_group.py | 23 +++++++++++++++++++++++
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/pyrit/models/seeds/seed_group.py b/pyrit/models/seeds/seed_group.py
index 820108a9a9..ccb313c231 100644
--- a/pyrit/models/seeds/seed_group.py
+++ b/pyrit/models/seeds/seed_group.py
@@ -13,6 +13,7 @@
 import logging
 import uuid
 from collections import defaultdict
+from copy import deepcopy
 from typing import TYPE_CHECKING, Annotated, Any
 
 from pydantic import BaseModel, ConfigDict, Field, model_validator
@@ -460,7 +461,7 @@ def _prompts_to_messages(self, prompts: Sequence[SeedPrompt], *, is_history: boo
                     original_value_data_type=prompt.data_type or "text",
                     conversation_id=str(prompt.prompt_group_id),
                     sequence=sequence,
-                    prompt_metadata=prompt.metadata or {},
+                    prompt_metadata=deepcopy(prompt.metadata) if prompt.metadata else {},
                 )
                 if is_history or piece.api_role in {"assistant", "tool"}:
                     piece.set_simulated_role()
diff --git a/tests/unit/models/test_seed_group.py b/tests/unit/models/test_seed_group.py
index 527ddad546..48b3b7ee3b 100644
--- a/tests/unit/models/test_seed_group.py
+++ b/tests/unit/models/test_seed_group.py
@@ -102,6 +102,29 @@ def test_seed_prompts_without_metadata_convert_to_messages() -> None:
     assert [message.get_piece().prompt_metadata for message in group.user_messages] == [{}, {}]
 
 
+def test_derived_message_metadata_is_independent_of_seed_metadata() -> None:
+    """Mutating a derived message's nested metadata must not change the source seed."""
+    group = SeedGroup(
+        seeds=[
+            SeedPrompt(value="Earlier request", role="user", sequence=0, metadata={"nested": {"labels": ["initial"]}}),
+            SeedPrompt(value="Next request", role="user", sequence=1, metadata={"nested": {"labels": ["next"]}}),
+        ]
+    )
+
+    history = group.prepended_conversation
+    assert history is not None
+    history[0].get_piece().prompt_metadata["nested"]["labels"].append("history")
+    next_message = group.next_message
+    assert next_message is not None
+    next_message.get_piece().prompt_metadata["nested"]["labels"].append("next-turn")
+
+    assert group.seeds[0].metadata == {"nested": {"labels": ["initial"]}}
+    assert group.seeds[1].metadata == {"nested": {"labels": ["next"]}}
+    later_history = group.prepended_conversation
+    assert later_history is not None
+    assert later_history[0].get_piece().prompt_metadata["nested"] == {"labels": ["initial"]}
+
+
 class TestSeedGroupInit:
     """Tests for SeedGroup initialization."""