diff --git a/miles/rollout/generate_hub/agentic_tool_call.py b/miles/rollout/generate_hub/agentic_tool_call.py
index feba568164..908361472a 100644
--- a/miles/rollout/generate_hub/agentic_tool_call.py
+++ b/miles/rollout/generate_hub/agentic_tool_call.py
@@ -112,6 +112,15 @@ async def generate(input: GenerateFnInput) -> GenerateFnOutput:
     for s in samples:
         s.metadata.update(agent_metadata or {})
 
+    # If the agent function reports wall-clock time spent outside policy generation
+    # (env/tool steps), surface it on Sample.non_generation_time so throughput
+    # accounting subtracts it. Must be equal across all turn-samples: merge_samples
+    # collapses them with _merge_equal_value, which asserts the values match.
+    ngt = ((agent_metadata or {}).get("agent_metrics") or {}).get("total_tool_time")
+    if ngt is not None:
+        for s in samples:
+            s.non_generation_time = ngt
+
     if max_seq_len is not None:
         samples = truncate_samples_by_total_tokens(samples, max_seq_len, input.state.tokenizer)