diff --git a/scripts/src/platform-infra-observability.ts b/scripts/src/platform-infra-observability.ts
index d128f950..d1681766 100644
--- a/scripts/src/platform-infra-observability.ts
+++ b/scripts/src/platform-infra-observability.ts
@@ -1350,6 +1350,9 @@ IMPORTANT_ATTRS = [
     "traceId", "otel.trace_id", "agentrun.stage", "runId", "commandId",
     "sessionId", "turnId", "threadId", "runnerJobId", "failureKind", "willRetry",
     "retryAttempt", "retryMax", "retryExhausted", "retryBackoffMs",
+    "idleMs", "idleSeconds", "idleThresholdMs", "idleThresholdSeconds",
+    "waitingFor", "lastEventLabel", "lastActivityAt", "lastActivityMs",
+    "lastNotificationAt", "lastNotificationMs", "lastToolCallAt",
     "upstreamHttpStatus", "upstreamHost", "providerErrorClass", "errorSummary",
     "terminalStatus", "phase", "message", "http.route", "http.status_code",
     "http.method", "eventType", "runnerId", "attemptId", "backendProfile",
@@ -1602,6 +1605,9 @@ IMPORTANT_ATTRS = [
     "traceId", "otel.trace_id", "agentrun.stage", "runId", "commandId",
     "sessionId", "turnId", "threadId", "runnerJobId", "failureKind", "willRetry",
     "retryAttempt", "retryMax", "retryExhausted", "retryBackoffMs",
+    "idleMs", "idleSeconds", "idleThresholdMs", "idleThresholdSeconds",
+    "waitingFor", "lastEventLabel", "lastActivityAt", "lastActivityMs",
+    "lastNotificationAt", "lastNotificationMs", "lastToolCallAt",
     "upstreamHttpStatus", "upstreamHost", "providerErrorClass", "errorSummary",
     "terminalStatus", "phase", "message", "http.route", "http.status_code",
     "http.response.status_code", "http.method", "http.request.method",
@@ -1966,6 +1972,9 @@ IMPORTANT_ATTRS = [
     "traceId", "otel.trace_id", "agentrun.stage", "runId", "commandId",
     "sessionId", "turnId", "threadId", "runnerJobId", "failureKind", "willRetry",
     "retryAttempt", "retryMax", "retryExhausted", "retryBackoffMs",
+    "idleMs", "idleSeconds", "idleThresholdMs", "idleThresholdSeconds",
+    "waitingFor", "lastEventLabel", "lastActivityAt", "lastActivityMs",
+    "lastNotificationAt", "lastNotificationMs", "lastToolCallAt",
     "upstreamHttpStatus", "upstreamHost", "providerErrorClass", "errorSummary",
     "terminalStatus", "phase", "message", "http.route", "http.status_code",
     "http.method", "eventType", "runnerId", "attemptId", "backendProfile",
@@ -2174,6 +2183,9 @@ def tiny_span(item):
         "fromSeq", "toSeq", "totalEvents", "hasMore", "fullTraceLoaded",
         "afterSeq", "rawEventCount", "failureKind", "willRetry",
         "retryAttempt", "retryMax", "retryExhausted", "retryBackoffMs",
+        "idleMs", "idleSeconds", "idleThresholdMs", "idleThresholdSeconds",
+        "waitingFor", "lastEventLabel", "lastActivityAt", "lastActivityMs",
+        "lastNotificationAt", "lastNotificationMs", "lastToolCallAt",
         "upstreamHttpStatus", "upstreamHost", "providerErrorClass", "errorSummary",
         "toolName", "type", "itemType", "itemId", "status", "exitCode",
         "durationMs", "cwd", "processId", "command", "commandFingerprint",
@@ -2460,7 +2472,7 @@ def projection_lag_summary(agentrun, read_model):
         "reasons": reasons,
     }
 
-def root_cause_candidates(http_summary, agentrun, read_model, lag_summary, error_spans):
+def root_cause_candidates(http_summary, agentrun, read_model, lag_summary, error_spans, idle_warning_spans):
     candidates = []
     if http_summary.get("actorForbidden"):
         candidates.append({
@@ -2514,6 +2526,14 @@ def root_cause_candidates(http_summary, agentrun, read_model, lag_summary, error
                 "sampleNames": sorted(set(str(item.get("name") or "") for item in error_spans))[:5],
             },
         })
+    if idle_warning_spans and agentrun.get("terminalStatus") in (None, ""):
+        candidates.append({
+            "code": "agentrun_runner_idle_warning_active",
+            "label": "AgentRun runner idle warning active",
+            "confidence": 0.72,
+            "summary": "AgentRun runner is still emitting idle warnings and no runner terminal span is present; inspect waitingFor/lastEventLabel before treating the Workbench UI as terminal.",
+            "evidence": [tiny_span(item) for item in idle_warning_spans[-3:]],
+        })
     candidates.sort(key=lambda item: item.get("confidence", 0), reverse=True)
     return candidates
 
@@ -2727,12 +2747,13 @@ spans = flat["spans"]
 services = flat["services"]
 business_trace_ids = flat["businessTraceIds"]
 error_spans = flat["errorSpans"]
+idle_warning_spans = [item for item in spans if str(item.get("name") or "") == "codex_stdio.idle_warning"]
 http_summary = http_status_summary(spans)
 agentrun = agentrun_summary(spans)
 read_model = hwlab_read_model_summary(spans)
 lag = projection_lag_summary(agentrun, read_model)
 identity = identity_from_spans(spans)
-candidates = root_cause_candidates(http_summary, agentrun, read_model, lag, error_spans)
+candidates = root_cause_candidates(http_summary, agentrun, read_model, lag, error_spans, idle_warning_spans)
 expected_services = ["hwlab-cloud-api", "agentrun-manager", "agentrun-runner"]
 service_path = {
     service: ("reached" if service in services else "missing")
@@ -2746,6 +2767,8 @@ if agentrun.get("terminalStatus") == "completed":
     facts.append("AgentRun completed")
 if lag.get("status") in ("confirmed", "suspected"):
     facts.append("HWLAB projection stale")
+if idle_warning_spans and agentrun.get("terminalStatus") in (None, ""):
+    facts.append("AgentRun runner idle warnings active")
 if not facts:
     facts.append("no dominant Code Agent root cause classified")
 summary = {
@@ -2769,6 +2792,8 @@ evidence = {
     "projectionSpanTail": [tiny_span(item) for item in read_model.get("projectionSpans", [])[-3:]],
     "errorSpanCount": len(error_spans),
     "errorSpanSampleNames": sorted(set(str(item.get("name") or "") for item in error_spans))[:5],
+    "idleWarningSpanCount": len(idle_warning_spans),
+    "idleWarningSpanTail": [tiny_span(item) for item in idle_warning_spans[-3:]],
 }
 payload = {
     "ok": trace_rc == 0 and len(spans) > 0,