add Langfuse tracing to agent runs and tool calls

agents/handover.py

@@ -26,17 +26,8 @@ async def run_handover(
     hubs: list[str] | None = None,
     mcp: MCPMultiClient | None = None,
     on_event: Any = None,
+    trace: Any = None,
 ) -> dict:
-    """Run the Shift Handover agent.
-
-    Args:
-        hubs: Hubs to cover (default: all 5).
-        mcp: Connected MCPMultiClient (shared + ops).
-        on_event: Optional async callback for real-time events.
-
-    Returns:
-        Handover brief result dict.
-    """
     target_hubs = hubs or ALL_HUBS
     run_start = time.time()
     errors = []
@@ -54,20 +45,27 @@ async def run_handover(
 
     async def _call(server, tool, args, is_live=False, timeout=15.0):
         t = time.time()
+        span = trace.span(name=tool, input=args, metadata={"server": server, "is_live": is_live}) if trace else None
         try:
             result = await asyncio.wait_for(
                 mcp.call_tool(server, tool, args), timeout=timeout,
             )
             lat = int((time.time() - t) * 1000)
+            if span:
+                span.end(output=result, metadata={"latency_ms": lat})
             await emit("tool_call_end", tool=tool, latency_ms=lat, is_live=is_live)
             return result
         except asyncio.TimeoutError:
             lat = int((time.time() - t) * 1000)
+            if span:
+                span.end(output={"error": "timeout"}, level="ERROR")
             await emit("tool_call_error", tool=tool, error="timeout", latency_ms=lat)
             errors.append(f"{tool}: timeout after {timeout}s")
             return None
         except Exception as e:
             lat = int((time.time() - t) * 1000)
+            if span:
+                span.end(output={"error": str(e)}, level="ERROR")
             await emit("tool_call_error", tool=tool, error=str(e), latency_ms=lat)
             errors.append(f"{tool}: {e}")
             return None