fix: align custom tool SSE lifecycle with OpenAI API compatibility

crates/agentic-server-core/src/executor/compaction.rs

@@ -86,9 +86,9 @@ fn item_has_meaningful_context(item: &InputItem) -> bool {
             }),
         },
         InputItem::FunctionCall(call) => !call.name.trim().is_empty() || !call.arguments.trim().is_empty(),
-        InputItem::FunctionCallOutput(output) => !output.output.trim().is_empty(),
+        InputItem::FunctionCallOutput(output) => output.output.has_content(),
         InputItem::CustomToolCall(call) => !call.name.trim().is_empty() || !call.input.trim().is_empty(),
-        InputItem::CustomToolCallOutput(output) => value_has_content(&output.output),
+        InputItem::CustomToolCallOutput(output) => output.output.has_content(),
         InputItem::Reasoning(reasoning) => {
             reasoning.content.iter().any(|content| !content.text.trim().is_empty())
                 || reasoning.summary.iter().any(value_has_content)
@@ -390,7 +390,7 @@ mod tests {
             user_message("first"),
             InputItem::FunctionCallOutput(FunctionToolResultMessage {
                 call_id: "call_1".to_owned(),
-                output: "tool output".to_owned(),
+                output: "tool output".into(),
             }),
             user_message("second"),
         ];
@@ -427,7 +427,7 @@ mod tests {
             user_message("hello context"),
             InputItem::FunctionCallOutput(FunctionToolResultMessage {
                 call_id: "call_1".to_owned(),
-                output: "substantial tool output".to_owned(),
+                output: "substantial tool output".into(),
             }),
         ]);
 

crates/agentic-server-core/src/executor/engine.rs

@@ -17,7 +17,7 @@ use super::gateway::{
     GatewayCallResult, LoopDecision, append_gateway_calls_to_new_input, append_output_items_to_input,
     append_tool_outputs, classify_round, emit_gateway_completed_events, emit_gateway_start_events,
     execute_and_emit_output_calls, execute_output_calls, gateway_event_plans, has_client_owned_calls,
-    is_gateway_owned_call, public_output_items,
+    is_client_custom_call, is_gateway_owned_call, public_output_items,
 };
 use super::gateway_accumulator::{GatewayStreamAccumulator, StreamEvent, error_sse_chunk};
 use crate::events::EventFrame;
@@ -262,13 +262,21 @@ async fn execute_and_emit_ordered_output_calls(
     let first_gateway_index = output_items
         .iter()
         .position(|item| matches!(item, OutputItem::FunctionCall(call) if is_gateway_owned_call(call, registry)));
-    let first_gateway_run_end = first_gateway_index.map_or(0, |start| {
-        output_items[start..]
-            .iter()
-            .take_while(|item| matches!(item, OutputItem::FunctionCall(call) if is_gateway_owned_call(call, registry)))
-            .count()
-            .saturating_add(start)
-    });
+    let first_gateway_run_end = first_gateway_index
+        .filter(|start| {
+            !output_items[..*start]
+                .iter()
+                .any(|item| matches!(item, OutputItem::FunctionCall(call) if is_client_custom_call(call, registry)))
+        })
+        .map_or(0, |start| {
+            output_items[start..]
+                .iter()
+                .take_while(
+                    |item| matches!(item, OutputItem::FunctionCall(call) if is_gateway_owned_call(call, registry)),
+                )
+                .count()
+                .saturating_add(start)
+        });
     let first_gateway_run_len = first_gateway_run_end.saturating_sub(first_gateway_index.unwrap_or(0));
     emit_gateway_start_events(&event_plans[..first_gateway_run_len], stream_accumulator, stream_sender)?;