rename model turn to sampling request (#9336)

We have two type of turns now: model and user turns. It's always
confusing to refer to either. Model turn is basically a sampling
request.

codex-rs/core/src/codex.rs

@@ -2528,17 +2528,17 @@ fn errors_to_info(errors: &[SkillError]) -> Vec<SkillErrorInfo> {
         .collect()
 }
 
-/// Takes a user message as input and runs a loop where, at each turn, the model
+/// Takes a user message as input and runs a loop where, at each sampling request, the model
 /// replies with either:
 ///
 /// - requested function calls
 /// - an assistant message
 ///
 /// While it is possible for the model to return multiple of these items in a
-/// single turn, in practice, we generally one item per turn:
+/// single sampling request, in practice, we generally one item per sampling request:
 ///
 /// - If the model requests a function call, we execute it and send the output
-///   back to the model in the next turn.
+///   back to the model in the next sampling request.
 /// - If the model sends only an assistant message, we record it in the
 ///   conversation history and consider the turn complete.
 ///
@@ -2611,13 +2611,13 @@ pub(crate) async fn run_turn(
             .collect::<Vec<ResponseItem>>();
 
         // Construct the input that we will send to the model.
-        let turn_input: Vec<ResponseItem> = {
+        let sampling_request_input: Vec<ResponseItem> = {
             sess.record_conversation_items(&turn_context, &pending_input)
                 .await;
             sess.clone_history().await.for_prompt()
         };
 
-        let turn_input_messages = turn_input
+        let sampling_request_input_messages = sampling_request_input
             .iter()
             .filter_map(|item| match parse_turn_item(item) {
                 Some(TurnItem::UserMessage(user_message)) => Some(user_message),
@@ -2625,21 +2625,21 @@ pub(crate) async fn run_turn(
             })
             .map(|user_message| user_message.message())
             .collect::<Vec<String>>();
-        match run_model_turn(
+        match run_sampling_request(
             Arc::clone(&sess),
             Arc::clone(&turn_context),
             Arc::clone(&turn_diff_tracker),
             &mut client_session,
-            turn_input,
+            sampling_request_input,
             cancellation_token.child_token(),
         )
         .await
         {
-            Ok(turn_output) => {
-                let TurnRunResult {
+            Ok(sampling_request_output) => {
+                let SamplingRequestResult {
                     needs_follow_up,
-                    last_agent_message: turn_last_agent_message,
-                } = turn_output;
+                    last_agent_message: sampling_request_last_agent_message,
+                } = sampling_request_output;
                 let total_usage_tokens = sess.get_total_token_usage().await;
                 let token_limit_reached = total_usage_tokens >= auto_compact_limit;
 
@@ -2650,13 +2650,13 @@ pub(crate) async fn run_turn(
                 }
 
                 if !needs_follow_up {
-                    last_agent_message = turn_last_agent_message;
+                    last_agent_message = sampling_request_last_agent_message;
                     sess.notifier()
                         .notify(&UserNotification::AgentTurnComplete {
                             thread_id: sess.conversation_id.to_string(),
                             turn_id: turn_context.sub_id.clone(),
                             cwd: turn_context.cwd.display().to_string(),
-                            input_messages: turn_input_messages,
+                            input_messages: sampling_request_input_messages,
                             last_assistant_message: last_agent_message.clone(),
                         });
                     break;
@@ -2712,14 +2712,14 @@ async fn run_auto_compact(sess: &Arc<Session>, turn_context: &Arc<TurnContext>)
         cwd = %turn_context.cwd.display()
     )
 )]
-async fn run_model_turn(
+async fn run_sampling_request(
     sess: Arc<Session>,
     turn_context: Arc<TurnContext>,
     turn_diff_tracker: SharedTurnDiffTracker,
     client_session: &mut ModelClientSession,
     input: Vec<ResponseItem>,
     cancellation_token: CancellationToken,
-) -> CodexResult<TurnRunResult> {
+) -> CodexResult<SamplingRequestResult> {
     let mcp_tools = sess
         .services
         .mcp_connection_manager
@@ -2753,7 +2753,7 @@ async fn run_model_turn(
 
     let mut retries = 0;
     loop {
-        let err = match try_run_turn(
+        let err = match try_run_sampling_request(
             Arc::clone(&router),
             Arc::clone(&sess),
             Arc::clone(&turn_context),
@@ -2793,7 +2793,9 @@ async fn run_model_turn(
                 }
                 _ => backoff(retries),
             };
-            warn!("stream disconnected - retrying turn ({retries}/{max_retries} in {delay:?})...",);
+            warn!(
+                "stream disconnected - retrying sampling request ({retries}/{max_retries} in {delay:?})...",
+            );
 
             // Surface retry information to any UI/front‑end so the
             // user understands what is happening instead of staring
@@ -2813,7 +2815,7 @@ async fn run_model_turn(
 }
 
 #[derive(Debug)]
-struct TurnRunResult {
+struct SamplingRequestResult {
     needs_follow_up: bool,
     last_agent_message: Option<String>,
 }
@@ -2845,7 +2847,7 @@ async fn drain_in_flight(
         model = %turn_context.client.get_model()
     )
 )]
-async fn try_run_turn(
+async fn try_run_sampling_request(
     router: Arc<ToolRouter>,
     sess: Arc<Session>,
     turn_context: Arc<TurnContext>,
@@ -2853,7 +2855,7 @@ async fn try_run_turn(
     turn_diff_tracker: SharedTurnDiffTracker,
     prompt: &Prompt,
     cancellation_token: CancellationToken,
-) -> CodexResult<TurnRunResult> {
+) -> CodexResult<SamplingRequestResult> {
     let rollout_item = RolloutItem::TurnContext(TurnContextItem {
         cwd: turn_context.cwd.clone(),
         approval_policy: turn_context.approval_policy,
@@ -2897,7 +2899,7 @@ async fn try_run_turn(
     let mut active_item: Option<TurnItem> = None;
     let mut should_emit_turn_diff = false;
     let receiving_span = trace_span!("receiving_stream");
-    let outcome: CodexResult<TurnRunResult> = loop {
+    let outcome: CodexResult<SamplingRequestResult> = loop {
         let handle_responses = trace_span!(
             parent: &receiving_span,
             "handle_responses",
@@ -2983,7 +2985,7 @@ async fn try_run_turn(
 
                 needs_follow_up |= sess.has_pending_input().await;
 
-                break Ok(TurnRunResult {
+                break Ok(SamplingRequestResult {
                     needs_follow_up,
                     last_agent_message,
                 });