diff --git a/posthog/test/ai/test_prompts.py b/posthog/test/ai/test_prompts.py
index 9a860f38..15d4b911 100644
--- a/posthog/test/ai/test_prompts.py
+++ b/posthog/test/ai/test_prompts.py
@@ -820,9 +820,15 @@ def test_mutating_a_result_config_does_not_pollute_the_cache(
         self, mock_get_session
     ):
         """Callers often mutate config before spreading it into an LLM call; that must not leak into later cache hits."""
+        # Nested values included: a shallow copy would pass the top-level mutations
+        # below but leak the nested one into the cache.
+        nested_config = {
+            "model": "gpt-4o",
+            "tools": [{"name": "search", "parameters": {"depth": 1}}],
+        }
         mock_get = mock_get_session.return_value.get
         mock_get.return_value = MockResponse(
-            json_data={**self.mock_prompt_response, "config": self.mock_config}
+            json_data={**self.mock_prompt_response, "config": nested_config}
         )
 
         prompts = Prompts(self.create_mock_posthog())
@@ -831,11 +837,18 @@ def test_mutating_a_result_config_does_not_pollute_the_cache(
         assert first.config is not None
         first.config["temperature"] = 0.9
         first.config.pop("model")
+        first.config["tools"][0]["parameters"]["depth"] = 99
 
         second = prompts.get("test-prompt", with_metadata=True)
 
         self.assertEqual(second.source, "cache")
-        self.assertEqual(second.config, self.mock_config)
+        self.assertEqual(
+            second.config,
+            {
+                "model": "gpt-4o",
+                "tools": [{"name": "search", "parameters": {"depth": 1}}],
+            },
+        )
 
     @parameterized.expand(
         [
diff --git a/references/public_api_snapshot.txt b/references/public_api_snapshot.txt
index 90f4f940..d83fbb74 100644
--- a/references/public_api_snapshot.txt
+++ b/references/public_api_snapshot.txt
@@ -425,6 +425,7 @@ attribute posthog.ai.openai_agents.processor.log = logging.getLogger('posthog')
 attribute posthog.ai.otel.spans.AI_SPAN_PREFIXES = ('gen_ai.', 'llm.', 'ai.', 'traceloop.')
 attribute posthog.ai.otel.spans.DEFAULT_HOST = 'https://us.i.posthog.com'
 attribute posthog.ai.prompts.APP_ENDPOINT = 'https://us.posthog.com'
+attribute posthog.ai.prompts.CachedPrompt.config = config
 attribute posthog.ai.prompts.CachedPrompt.fetched_at = fetched_at
 attribute posthog.ai.prompts.CachedPrompt.label = label
 attribute posthog.ai.prompts.CachedPrompt.name = name
@@ -432,6 +433,7 @@ attribute posthog.ai.prompts.CachedPrompt.prompt = prompt
 attribute posthog.ai.prompts.CachedPrompt.version = version
 attribute posthog.ai.prompts.DEFAULT_CACHE_TTL_SECONDS = 300
 attribute posthog.ai.prompts.PromptCacheKey = tuple[str, Optional[int], Optional[str]]
+attribute posthog.ai.prompts.PromptResult.config: Optional[Dict[str, Any]] = None
 attribute posthog.ai.prompts.PromptResult.label: Optional[str] = None
 attribute posthog.ai.prompts.PromptResult.name: Optional[str] = None
 attribute posthog.ai.prompts.PromptResult.prompt: str
@@ -887,8 +889,8 @@ class posthog.ai.openai.openai_providers.AzureOpenAI(posthog_client: Optional[Po
 class posthog.ai.openai_agents.processor.PostHogTracingProcessor(client: Optional[Client] = None, distinct_id: Optional[Union[str, Callable[[Trace], Optional[str]]]] = None, privacy_mode: bool = False, groups: Optional[Dict[str, Any]] = None, properties: Optional[Dict[str, Any]] = None)
 class posthog.ai.otel.exporter.PostHogTraceExporter(api_key: str, host: str = DEFAULT_HOST)
 class posthog.ai.otel.processor.PostHogSpanProcessor(api_key: str, host: str = DEFAULT_HOST)
-class posthog.ai.prompts.CachedPrompt(prompt: str, fetched_at: float, name: str, version: int, label: Optional[str] = None)
-class posthog.ai.prompts.PromptResult(source: PromptSource, prompt: str, name: Optional[str] = None, version: Optional[int] = None, label: Optional[str] = None)
+class posthog.ai.prompts.CachedPrompt(prompt: str, fetched_at: float, name: str, version: int, label: Optional[str] = None, config: Optional[Dict[str, Any]] = None)
+class posthog.ai.prompts.PromptResult(source: PromptSource, prompt: str, name: Optional[str] = None, version: Optional[int] = None, label: Optional[str] = None, config: Optional[Dict[str, Any]] = None)
 class posthog.ai.prompts.Prompts(posthog: Optional[Any] = None, *, personal_api_key: Optional[str] = None, project_api_key: Optional[str] = None, host: Optional[str] = None, default_cache_ttl_seconds: Optional[int] = None, capture_errors: bool = False)
 class posthog.ai.stream.AsyncStreamWrapper(generator: AsyncGenerator[T, None], stream: Optional[Any] = None)
 class posthog.ai.types.FormattedFunctionCall