fix: langfuse v4 SDK compatibility and pass user message as trace input

services/chat/app/deep_agent.py

@@ -528,7 +528,9 @@ def _infer_floating_domain_rule_based(message: str, context: dict[str, Any]) ->
     return {"type": "task", "id": None, "section": None}
 
 
-async def _infer_floating_domain(message: str, context: dict[str, Any]) -> dict[str, str | None]:
+async def _infer_floating_domain(
+    message: str, context: dict[str, Any], *, langfuse_handler: Any | None = None,
+) -> dict[str, str | None]:
     resolved_project_id = context.get("resolved_project_id") if isinstance(context, dict) else None
     project_id = resolved_project_id if isinstance(resolved_project_id, str) and resolved_project_id else None
 
@@ -538,10 +540,14 @@ async def _infer_floating_domain(message: str, context: dict[str, Any]) -> dict[
     }
 
     try:
-        llm = get_llm()
+        classifier_prompt = _get_system_prompt(
+            "floating_domain_classifier", _FLOATING_DOMAIN_CLASSIFIER_SYSTEM,
+        )
+        callbacks = _build_callbacks(langfuse_handler)
+        llm = get_llm(callbacks=callbacks)
         response = await llm.ainvoke(
             [
-                SystemMessage(content=_FLOATING_DOMAIN_CLASSIFIER_SYSTEM),
+                SystemMessage(content=classifier_prompt),
                 HumanMessage(
                     content=(
                         f"Message:\n{message}\n\n"
@@ -784,7 +790,7 @@ async def run_home(user_id: str, message: str, context: dict[str, Any], *, langf
 
 async def run_floating(user_id: str, message: str, context: dict[str, Any], *, langfuse_handler: Any | None = None) -> tuple[str, dict[str, str | None]]:
     prepared_context = await _prepare_context(message, context)
-    domain = await _infer_floating_domain(message, prepared_context)
+    domain = await _infer_floating_domain(message, prepared_context, langfuse_handler=langfuse_handler)
     system_prompt = _get_system_prompt("floating_system", _FLOATING_SINGLE_AGENT_SYSTEM)
     response = await _run_single_agent(
         user_id=user_id,
@@ -835,7 +841,7 @@ async def run_floating_stream(
     langfuse_handler: Any | None = None,
 ) -> AsyncGenerator[tuple[str, Any], None]:
     prepared_context = await _prepare_context(message, context)
-    domain = await _infer_floating_domain(message, prepared_context)
+    domain = await _infer_floating_domain(message, prepared_context, langfuse_handler=langfuse_handler)
     yield "floating_domain", domain
 
     system_prompt = _get_system_prompt("floating_system", _FLOATING_SINGLE_AGENT_SYSTEM)