diff --git a/codex-rs/core/src/agent/control.rs b/codex-rs/core/src/agent/control.rs
index ef102f23ac..3ec0d55157 100644
--- a/codex-rs/core/src/agent/control.rs
+++ b/codex-rs/core/src/agent/control.rs
@@ -322,15 +322,19 @@ impl AgentControl {
             )
             .await;
         }
-        if let SpawnAgentForkMode::LastNTurns(last_n_turns) = fork_mode {
-            forked_rollout_items =
-                truncate_rollout_to_last_n_fork_turns(&forked_rollout_items, *last_n_turns);
+        match fork_mode {
+            SpawnAgentForkMode::FullHistory => {
+                let fork_boundary = fork_reference_user_message_boundary(&forked_rollout_items);
+                forked_rollout_items.push(RolloutItem::ForkReference(ForkReferenceItem {
+                    rollout_path: rollout_path.clone(),
+                    nth_user_message: fork_boundary,
+                }));
+            }
+            SpawnAgentForkMode::LastNTurns(last_n_turns) => {
+                forked_rollout_items =
+                    truncate_rollout_to_last_n_fork_turns(&forked_rollout_items, *last_n_turns);
+            }
         }
-        let fork_boundary = fork_reference_user_message_boundary(&forked_rollout_items);
-        forked_rollout_items.push(RolloutItem::ForkReference(ForkReferenceItem {
-            rollout_path: rollout_path.clone(),
-            nth_user_message: fork_boundary,
-        }));
 
         let mut output =
             FunctionCallOutputPayload::from_text(FORKED_SPAWN_AGENT_OUTPUT_MESSAGE.to_string());
diff --git a/codex-rs/rollout/src/recorder_tests.rs b/codex-rs/rollout/src/recorder_tests.rs
index f999d64402..fe80cf691b 100644
--- a/codex-rs/rollout/src/recorder_tests.rs
+++ b/codex-rs/rollout/src/recorder_tests.rs
@@ -35,7 +35,8 @@ fn test_config(codex_home: &Path) -> RolloutConfig {
 fn write_session_file(root: &Path, ts: &str, uuid: Uuid) -> std::io::Result<PathBuf> {
     let day_dir = root.join("sessions/2025/01/03");
     fs::create_dir_all(&day_dir)?;
-    let path = day_dir.join(format!("rollout-{ts}-{uuid}.jsonl"));
+    let file_ts = ts.replace(':', "-");
+    let path = day_dir.join(format!("rollout-{file_ts}-{uuid}.jsonl"));
     let mut file = File::create(&path)?;
     let meta = serde_json::json!({
         "timestamp": ts,