diff --git a/codex-rs/codex-api/src/endpoint/realtime_websocket/methods.rs b/codex-rs/codex-api/src/endpoint/realtime_websocket/methods.rs
index 9fcca1c3e3..ad26549a26 100644
--- a/codex-rs/codex-api/src/endpoint/realtime_websocket/methods.rs
+++ b/codex-rs/codex-api/src/endpoint/realtime_websocket/methods.rs
@@ -993,6 +993,22 @@ mod tests {
         );
     }
 
+    #[test]
+    fn parse_v1_input_transcript_turn_marked_event() {
+        let payload = json!({
+            "type": "conversation.input_transcript.turn_marked",
+            "transcript": "hello realtime"
+        })
+        .to_string();
+
+        assert_eq!(
+            parse_realtime_event(payload.as_str(), RealtimeEventParser::V1),
+            Some(RealtimeEvent::InputTranscriptDone(RealtimeTranscriptDone {
+                text: "hello realtime".to_string(),
+            }))
+        );
+    }
+
     #[test]
     fn parse_output_transcript_delta_event() {
         let payload = json!({
@@ -1581,6 +1597,10 @@ mod tests {
                 .expect("text");
             let third_json: Value = serde_json::from_str(&third).expect("json");
             assert_eq!(third_json["type"], "conversation.item.create");
+            assert_eq!(
+                third_json["item"]["content"][0]["type"],
+                Value::String("input_text".to_string())
+            );
             assert_eq!(third_json["item"]["content"][0]["text"], "hello agent");
 
             let fourth = ws
diff --git a/codex-rs/codex-api/src/endpoint/realtime_websocket/methods_v1.rs b/codex-rs/codex-api/src/endpoint/realtime_websocket/methods_v1.rs
index 19e4fa203a..0f1a269082 100644
--- a/codex-rs/codex-api/src/endpoint/realtime_websocket/methods_v1.rs
+++ b/codex-rs/codex-api/src/endpoint/realtime_websocket/methods_v1.rs
@@ -21,7 +21,7 @@ pub(super) fn conversation_item_create_message(text: String) -> RealtimeOutbound
             r#type: ConversationItemType::Message,
             role: ConversationRole::User,
             content: vec![ConversationItemContent {
-                r#type: ConversationContentType::Text,
+                r#type: ConversationContentType::InputText,
                 text,
             }],
         }),
diff --git a/codex-rs/codex-api/src/endpoint/realtime_websocket/protocol.rs b/codex-rs/codex-api/src/endpoint/realtime_websocket/protocol.rs
index d689f6ea96..5df4c0c503 100644
--- a/codex-rs/codex-api/src/endpoint/realtime_websocket/protocol.rs
+++ b/codex-rs/codex-api/src/endpoint/realtime_websocket/protocol.rs
@@ -199,7 +199,6 @@ pub(super) struct ConversationItemContent {
 #[derive(Debug, Clone, Copy, Serialize)]
 #[serde(rename_all = "snake_case")]
 pub(super) enum ConversationContentType {
-    Text,
     InputText,
 }
 
diff --git a/codex-rs/codex-api/src/endpoint/realtime_websocket/protocol_v1.rs b/codex-rs/codex-api/src/endpoint/realtime_websocket/protocol_v1.rs
index 3c1d25aed7..a464852244 100644
--- a/codex-rs/codex-api/src/endpoint/realtime_websocket/protocol_v1.rs
+++ b/codex-rs/codex-api/src/endpoint/realtime_websocket/protocol_v1.rs
@@ -43,7 +43,8 @@ pub(super) fn parse_realtime_event_v1(payload: &str) -> Option<RealtimeEvent> {
         | "conversation.item.input_audio_transcription.delta" => {
             parse_transcript_delta_event(&parsed, "delta").map(RealtimeEvent::InputTranscriptDelta)
         }
-        "conversation.item.input_audio_transcription.completed" => {
+        "conversation.input_transcript.turn_marked"
+        | "conversation.item.input_audio_transcription.completed" => {
             parse_transcript_done_event(&parsed, "transcript")
                 .map(RealtimeEvent::InputTranscriptDone)
         }
diff --git a/codex-rs/core/src/realtime_conversation.rs b/codex-rs/core/src/realtime_conversation.rs
index 249b3ae15f..7f71142e19 100644
--- a/codex-rs/core/src/realtime_conversation.rs
+++ b/codex-rs/core/src/realtime_conversation.rs
@@ -641,12 +641,14 @@ async fn prepare_realtime_start(
             realtime_request_headers(
                 requested_realtime_session_id.as_deref(),
                 Some(realtime_api_key.as_str()),
+                version,
             )?
         }
         ConversationStartTransport::Webrtc { .. } => {
             realtime_request_headers(
                 requested_realtime_session_id.as_deref(),
                 /*api_key*/ None,
+                version,
             )?
         }
     };
@@ -973,9 +975,14 @@ fn realtime_api_key(auth: Option<&CodexAuth>, provider: &ModelProviderInfo) -> C
 fn realtime_request_headers(
     realtime_session_id: Option<&str>,
     api_key: Option<&str>,
+    version: RealtimeWsVersion,
 ) -> CodexResult<Option<HeaderMap>> {
     let mut headers = HeaderMap::new();
 
+    if version == RealtimeWsVersion::V1 {
+        headers.insert("openai-alpha", HeaderValue::from_static("quicksilver=v1"));
+    }
+
     if let Some(realtime_session_id) = realtime_session_id
         && let Ok(realtime_session_id) = HeaderValue::from_str(realtime_session_id)
     {
diff --git a/codex-rs/core/src/realtime_conversation_tests.rs b/codex-rs/core/src/realtime_conversation_tests.rs
index a146c43869..b67205ef8f 100644
--- a/codex-rs/core/src/realtime_conversation_tests.rs
+++ b/codex-rs/core/src/realtime_conversation_tests.rs
@@ -1,9 +1,11 @@
 use super::RealtimeHandoffState;
 use super::RealtimeSessionKind;
 use super::realtime_delegation_from_handoff;
+use super::realtime_request_headers;
 use super::realtime_text_from_handoff_request;
 use super::wrap_realtime_delegation_input;
 use async_channel::bounded;
+use codex_config::config_toml::RealtimeWsVersion;
 use codex_protocol::protocol::RealtimeHandoffRequested;
 use codex_protocol::protocol::RealtimeTranscriptEntry;
 use pretty_assertions::assert_eq;
@@ -137,3 +139,28 @@ async fn clears_active_handoff_explicitly() {
     *state.active_handoff.lock().await = None;
     assert_eq!(state.active_handoff.lock().await.clone(), None);
 }
+
+#[test]
+fn uses_quicksilver_alpha_header_for_realtime_v1() {
+    let headers =
+        realtime_request_headers(Some("session_1"), Some("sk-test"), RealtimeWsVersion::V1)
+            .expect("headers")
+            .expect("headers");
+
+    assert_eq!(
+        headers
+            .get("openai-alpha")
+            .and_then(|value| value.to_str().ok()),
+        Some("quicksilver=v1")
+    );
+}
+
+#[test]
+fn omits_quicksilver_alpha_header_for_realtime_v2() {
+    let headers =
+        realtime_request_headers(Some("session_1"), Some("sk-test"), RealtimeWsVersion::V2)
+            .expect("headers")
+            .expect("headers");
+
+    assert!(headers.get("openai-alpha").is_none());
+}