diff --git a/tests/integration/multi-instance/multi_instance_test.go b/tests/integration/multi-instance/multi_instance_test.go
index 408765b2..13018213 100644
--- a/tests/integration/multi-instance/multi_instance_test.go
+++ b/tests/integration/multi-instance/multi_instance_test.go
@@ -153,7 +153,7 @@ func TestTwoInstancesOverSharedPG(t *testing.T) {
 				t.Fatalf("stale event replayed: seq %d <= since %d", ev.seq, lastSeq)
 			}
 		case <-time.After(8 * time.Second):
-			t.Fatal("event written via A not visible on B SSE within 8s")
+			t.Fatalf("event written via A not visible on B SSE within 8s: no event with seq > %d observed on %s", lastSeq, e.instanceOf(uc.streamB))
 		}
 	})
 
@@ -212,17 +212,24 @@ func TestTwoInstancesOverSharedPG(t *testing.T) {
 		// （interrupted），随后原实例重新占用会话并推进。
 		e.a = e.startInstance(t, e.a.name, strings.TrimPrefix(e.a.base, "http://"))
 		var detail map[string]any
-		deadline := time.Now().Add(httpWait)
+		var statuses []string
+		reconciled := false
+		start := time.Now()
+		deadline := start.Add(httpWait)
 		for time.Now().Before(deadline) {
 			e.do(t, uc.api, "GET", "/api/conversations/"+convID, nil, &detail)
-			if runs, ok := detail["runs"].([]any); ok && len(runs) > 0 {
-				last, _ := runs[len(runs)-1].(map[string]any)
-				if last["status"] == "interrupted" {
-					break
-				}
+			statuses = runStatuses(detail)
+			if n := len(statuses); n > 0 && statuses[n-1] == "interrupted" {
+				reconciled = true
+				break
 			}
 			time.Sleep(300 * time.Millisecond)
 		}
+		if !reconciled {
+			// 不能落到下面的 POST：未收口时它会得到看似无关的 409 in-flight。
+			t.Fatalf("restarted %s never reported the crashed run as interrupted: waited %v (budget %v), last run status never became \"interrupted\"; run statuses %v; log:\n%s",
+				e.instanceOf(uc.api), time.Since(start).Round(time.Millisecond), httpWait, statuses, e.a.log.String())
+		}
 		e.do(t, uc.api, "POST", "/api/conversations/"+convID+"/messages", map[string]any{"text": "A resumes after restart"}, nil)
 	})
 
@@ -230,6 +237,36 @@ func TestTwoInstancesOverSharedPG(t *testing.T) {
 		e.killNine(t, e.b)
 		e.b = e.startInstance(t, e.b.name, strings.TrimPrefix(e.b.base, "http://"))
 
+		// 断言前先等重启实例给出完整的恢复视图：对账收口的 interrupted run 可见，
+		// 且会话内无进行中 run。断言本身不依赖这次轮询的结果。
+		var statuses []string
+		recovered := false
+		start := time.Now()
+		readyBy := start.Add(httpWait)
+		for time.Now().Before(readyBy) {
+			var view map[string]any
+			e.do(t, uc.apiB, "GET", "/api/conversations/"+convID, nil, &view)
+			statuses = runStatuses(view)
+			interrupted, busy := false, false
+			for _, s := range statuses {
+				switch s {
+				case "interrupted":
+					interrupted = true
+				case "pending", "running", "waiting_hitl":
+					busy = true
+				}
+			}
+			if interrupted && !busy {
+				recovered = true
+				break
+			}
+			time.Sleep(300 * time.Millisecond)
+		}
+		if !recovered {
+			t.Fatalf("restarted %s never showed the recovered view (an interrupted run and no pending/running/waiting_hitl run): waited %v (budget %v); run statuses %v; logA:\n%s\nlogB:\n%s",
+				e.instanceOf(uc.apiB), time.Since(start).Round(time.Millisecond), httpWait, statuses, e.a.log.String(), e.b.log.String())
+		}
+
 		var detail map[string]any
 		e.do(t, uc.apiB, "GET", "/api/conversations/"+convID, nil, &detail)
 		msgs, _ := detail["messages"].([]any)
@@ -255,7 +292,7 @@ func TestTwoInstancesOverSharedPG(t *testing.T) {
 				}
 				seen = ev.seq
 			case <-deadline:
-				t.Fatalf("replay stalled at seq %d / %d", seen, lastSeq)
+				t.Fatalf("replay stalled at seq %d / %d: event seq %d never observed on %s SSE within 15s", seen, lastSeq, seen+1, e.instanceOf(uc.streamB))
 			}
 		}
 		// 重启后写入仍可推进。
@@ -410,6 +447,7 @@ func (e *env) uploadArtifact(t *testing.T, c *http.Client, projectID, name strin
 
 func (e *env) waitHealthy(t *testing.T, inst *instance) {
 	t.Helper()
+	last := "no probe completed"
 	deadline := time.Now().Add(60 * time.Second)
 	for time.Now().Before(deadline) {
 		resp, err := http.Get(inst.base + "/api/health")
@@ -419,10 +457,13 @@ func (e *env) waitHealthy(t *testing.T, inst *instance) {
 			if resp.StatusCode == http.StatusOK || resp.StatusCode == http.StatusUnauthorized {
 				return
 			}
+			last = "status " + strconv.Itoa(resp.StatusCode)
+		} else {
+			last = err.Error()
 		}
 		time.Sleep(300 * time.Millisecond)
 	}
-	t.Fatalf("instance %s not healthy in 60s; log:\n%s", inst.name, inst.log.String())
+	t.Fatalf("instance %s (%s) not healthy in 60s: GET /api/health never returned 200/401 (last probe: %s); log:\n%s", inst.name, inst.base, last, inst.log.String())
 }
 
 func (e *env) stopInstance(inst *instance) {
@@ -642,6 +683,27 @@ func (e *env) baseFor(c *http.Client) string {
 	return e.a.base
 }
 
+// instanceOf 给出 client 实际轮询的实例（名 + 地址），供有界等待的失败信息定位。
+func (e *env) instanceOf(c *http.Client) string {
+	base := e.baseFor(c)
+	if e.b != nil && base == e.b.base {
+		return e.b.name + " (" + base + ")"
+	}
+	return e.a.name + " (" + base + ")"
+}
+
+// runStatuses 按顺序取会话详情里各 run 的状态，供等待条件与失败信息复用。
+func runStatuses(detail map[string]any) []string {
+	runs, _ := detail["runs"].([]any)
+	out := make([]string, 0, len(runs))
+	for _, r := range runs {
+		m, _ := r.(map[string]any)
+		s, _ := m["status"].(string)
+		out = append(out, s)
+	}
+	return out
+}
+
 // ---- 场景辅助 ----
 
 type sseEvent struct {
@@ -671,10 +733,13 @@ func (e *env) postMessage(t *testing.T, c *http.Client, convID, text string) {
 
 func (e *env) waitConversationIdle(t *testing.T, c *http.Client, convID string, within time.Duration) {
 	t.Helper()
-	deadline := time.Now().Add(within)
+	var statuses []string
+	start := time.Now()
+	deadline := start.Add(within)
 	for time.Now().Before(deadline) {
 		var detail map[string]any
 		e.do(t, c, "GET", "/api/conversations/"+convID, nil, &detail)
+		statuses = runStatuses(detail)
 		busy := false
 		if runs, ok := detail["runs"].([]any); ok {
 			for _, r := range runs {
@@ -690,7 +755,8 @@ func (e *env) waitConversationIdle(t *testing.T, c *http.Client, convID string,
 		}
 		time.Sleep(300 * time.Millisecond)
 	}
-	t.Fatalf("conversation %s still busy after %v", convID, within)
+	t.Fatalf("conversation %s still busy on %s: waited %v (budget %v) and never observed all runs out of pending/running/waiting_hitl; run statuses %v",
+		convID, e.instanceOf(c), time.Since(start).Round(time.Millisecond), within, statuses)
 }
 
 func (e *env) lastSeq(t *testing.T, c *http.Client, convID string) int64 {
@@ -755,11 +821,17 @@ func (e *env) subscribe(t *testing.T, c *http.Client, convID string, since int64
 
 func (e *env) waitActiveHITL(t *testing.T, c *http.Client, convID string) hitlCard {
 	t.Helper()
-	deadline := time.Now().Add(15 * time.Second)
+	var statuses []string
+	cardCount := 0
+	start := time.Now()
+	deadline := start.Add(15 * time.Second)
 	for time.Now().Before(deadline) {
 		var detail map[string]any
 		e.do(t, c, "GET", "/api/conversations/"+convID, nil, &detail)
-		if cards, ok := detail["activeHitl"].([]any); ok && len(cards) > 0 {
+		statuses = runStatuses(detail)
+		cards, ok := detail["activeHitl"].([]any)
+		cardCount = len(cards)
+		if ok && len(cards) > 0 {
 			m, _ := cards[0].(map[string]any)
 			id, _ := m["id"].(string)
 			runID, _ := m["runId"].(string)
@@ -769,21 +841,27 @@ func (e *env) waitActiveHITL(t *testing.T, c *http.Client, convID string) hitlCa
 		}
 		time.Sleep(300 * time.Millisecond)
 	}
-	t.Fatalf("no active HITL card in 15s; logA:\n%s", e.a.log.String())
+	t.Fatalf("no active HITL card with id and runId on %s for conversation %s: waited %v (budget 15s); last activeHitl count %d, run statuses %v; logA:\n%s",
+		e.instanceOf(c), convID, time.Since(start).Round(time.Millisecond), cardCount, statuses, e.a.log.String())
 	return hitlCard{}
 }
 
 func (e *env) waitRunStatus(t *testing.T, c *http.Client, runID, status string) {
 	t.Helper()
-	deadline := time.Now().Add(httpWait)
+	observed := "<none>"
+	start := time.Now()
+	deadline := start.Add(httpWait)
 	for time.Now().Before(deadline) {
 		var out map[string]any
 		e.do(t, c, "GET", "/api/runs/"+runID, nil, &out)
 		run, _ := out["run"].(map[string]any)
-		if s, _ := run["status"].(string); s == status {
+		s, _ := run["status"].(string)
+		if s == status {
 			return
 		}
+		observed = s
 		time.Sleep(300 * time.Millisecond)
 	}
-	t.Fatalf("run %s not %s within %v", runID, status, httpWait)
+	t.Fatalf("run %s not %s on %s: waited %v (budget %v), last observed status %q; logA:\n%s",
+		runID, status, e.instanceOf(c), time.Since(start).Round(time.Millisecond), httpWait, observed, e.a.log.String())
 }