diff --git a/internal/coordinator/engine.go b/internal/coordinator/engine.go
index ff274860..c2cfb383 100644
--- a/internal/coordinator/engine.go
+++ b/internal/coordinator/engine.go
@@ -405,10 +405,10 @@ func (e *CoordinatorEngine) handleAmbiguousConsult(ctx context.Context, cand *in
 		projName = "当前项目"
 	}
 
-	// 若用户输入实质上包含具体的技术测试、方案、难点或业务要点询问，不应机械回复商业接待犹豫套话
-	if strings.Contains(rawInput, "测试") || strings.Contains(rawInput, "验证") || strings.Contains(rawInput, "型检") ||
+	// 只在低置信度的模糊咨询里，才用关键词改走测试分析。高置信度保持原意图。
+	if cand.Confidence < 0.6 && (strings.Contains(rawInput, "测试") || strings.Contains(rawInput, "验证") || strings.Contains(rawInput, "型检") ||
 		strings.Contains(rawInput, "难点") || strings.Contains(rawInput, "注意") || strings.Contains(rawInput, "比较难") ||
-		strings.Contains(rawInput, "方案") {
+		strings.Contains(rawInput, "方案")) {
 		if cand.FilledSlots == nil {
 			cand.FilledSlots = make(map[string]string)
 		}
@@ -482,8 +482,14 @@ func (e *CoordinatorEngine) handleQueryProgress(ctx context.Context, cand *inten
 			projName = "肌骨超声AI辅助诊断系统"
 		}
 
+		greet := strings.TrimSpace(userCtx.User.Name)
+		if greet == "" {
+			greet = "您好"
+		} else {
+			greet += "，您好"
+		}
 		var sb strings.Builder
-		sb.WriteString(fmt.Sprintf("张工您好！针对「%s」的系统验证方案（SVP）与型式检验要求，我为您梳理以下核心难点项目与特别注意事项：\n\n", projName))
+		sb.WriteString(fmt.Sprintf("%s！针对「%s」的系统验证方案（SVP）与型式检验要求，我为您梳理以下核心难点项目与特别注意事项：\n\n", greet, projName))
 		sb.WriteString("### 一、 核心测试难点项目\n\n")
 		sb.WriteString("1. **声学输出安全与探头表面温升极限（GB 9706.237-2020）**\n")
 		sb.WriteString("   • **难点分析**：肌骨超声常需配合高频线阵探头（10-18MHz）进行浅表滑膜微血流彩色多普勒（CDFI/Power Doppler）检测。连续高占空比发射脉冲会导致探头声透镜声吸收发热。根据强标要求，探头施加于人体的表面温升严禁超过 **41℃**，同时机械指数（MI）需严格低于 1.9，热指数（TIS/TIB）需低于 1.0。\n")
@@ -499,7 +505,7 @@ func (e *CoordinatorEngine) handleQueryProgress(ctx context.Context, cand *inten
 		sb.WriteString("• **电磁兼容（EMC GB 9706.102-2021）抗扰度储备**：高频微弱回波信号接收通道抗射频电磁场辐射敏感度高，测试方案中需提前验证探头线缆双层屏蔽接地与机箱屏蔽缝隙，避免正式型检时辐射发射（RE）超标返工；\n")
 		sb.WriteString("• **DICOM 与数据脱敏合规**：软件系统测试中，所有导出样本、测试影像的患者个人隐私标识（PII）脱敏规则需执行 100% 覆盖率验证；\n")
 		sb.WriteString("• **极端异常输入与容错安全防呆**：探头带电热插拔、探头声透镜声胶脱落阻抗异常检测、长时间无操作探头自动降频防发热休眠逻辑，均需设计破坏性负向测试用例。\n\n")
-		sb.WriteString("💡 **建议行动**：张工，若您需要，我可以为您起草该模块对应的《系统验证方案 (SVP) 关键测试用例矩阵》，列出详细的测试条件、前置配置与合格判据。")
+		sb.WriteString("💡 **建议行动**：若您需要，我可以为您起草该模块对应的《系统验证方案 (SVP) 关键测试用例矩阵》，列出详细的测试条件、前置配置与合格判据。")
 
 		return &CoordinationResult{
 			Status:          StatusAccepted,
@@ -928,10 +934,10 @@ func (e *CoordinatorEngine) handleTriggerTask(ctx context.Context, cand *intent.
 
 	var projectID, userID int64
 	if userCtx.Project.ID != "" {
-		fmt.Sscanf(userCtx.Project.ID, "%d", &projectID)
+		projectID = parseDecimalID(userCtx.Project.ID)
 	}
 	if userCtx.User.ID != "" {
-		fmt.Sscanf(userCtx.User.ID, "%d", &userID)
+		userID = parseDecimalID(userCtx.User.ID)
 	}
 
 	taskRes, err := e.tasks().ExecuteTask(ctx, stageflow.TaskRunRequest{
@@ -1065,10 +1071,10 @@ func (e *CoordinatorEngine) handleTriggerAdhocTask(ctx context.Context, cand *in
 
 	var projectID, userID int64
 	if userCtx.Project.ID != "" {
-		fmt.Sscanf(userCtx.Project.ID, "%d", &projectID)
+		projectID = parseDecimalID(userCtx.Project.ID)
 	}
 	if userCtx.User.ID != "" {
-		fmt.Sscanf(userCtx.User.ID, "%d", &userID)
+		userID = parseDecimalID(userCtx.User.ID)
 	}
 
 	if st := stream.FromContext(ctx); st != nil {
@@ -1822,3 +1828,17 @@ func (e *CoordinatorEngine) handleQueryUserRights(ctx context.Context, cand *int
 		UpdatedContext: userCtx,
 	}, nil
 }
+
+// parseDecimalID accepts only a non-negative decimal integer.
+// Values like u_sess_* must not become UserID 0 via a partial Sscanf match.
+func parseDecimalID(raw string) int64 {
+	raw = strings.TrimSpace(raw)
+	if raw == "" {
+		return 0
+	}
+	n, err := strconv.ParseInt(raw, 10, 64)
+	if err != nil || n < 0 {
+		return 0
+	}
+	return n
+}
diff --git a/internal/coordinator/engine_test.go b/internal/coordinator/engine_test.go
index 6776105d..4077eba3 100644
--- a/internal/coordinator/engine_test.go
+++ b/internal/coordinator/engine_test.go
@@ -981,4 +981,10 @@ func TestCoordinatorEngine_TestingAnalysis(t *testing.T) {
 	if strings.Contains(res.NaturalReply, "完全理解您想再掂量一下") {
 		t.Errorf("reply must not contain commercial triage boilerplate, got: %s", res.NaturalReply)
 	}
+	if !strings.Contains(res.NaturalReply, "张工，您好") {
+		t.Errorf("greeting must use the user name, got: %s", res.NaturalReply)
+	}
+	if strings.Contains(res.NaturalReply, "张工您好") {
+		t.Errorf("hardcoded greeting must be gone, got: %s", res.NaturalReply)
+	}
 }
diff --git a/internal/coordinator/parse_id_test.go b/internal/coordinator/parse_id_test.go
new file mode 100644
index 00000000..adb5ca19
--- /dev/null
+++ b/internal/coordinator/parse_id_test.go
@@ -0,0 +1,18 @@
+package coordinator
+
+import "testing"
+
+func TestParseDecimalIDRejectsSessionTokens(t *testing.T) {
+	if got := parseDecimalID("u_sess_12"); got != 0 {
+		t.Fatalf("session token parsed as %d", got)
+	}
+	if got := parseDecimalID("108abc"); got != 0 {
+		t.Fatalf("partial decimal parsed as %d", got)
+	}
+	if got := parseDecimalID("108"); got != 108 {
+		t.Fatalf("got %d", got)
+	}
+	if got := parseDecimalID(" 0 "); got != 0 {
+		t.Fatalf("got %d", got)
+	}
+}
diff --git a/internal/server/server.go b/internal/server/server.go
index d894483e..78447c65 100644
--- a/internal/server/server.go
+++ b/internal/server/server.go
@@ -406,6 +406,32 @@ func (s *Server) cleanStaleSessionsLocked(ttl time.Duration) int {
 	return cleaned
 }
 
+const maxLiveSessions = 4096
+
+func (s *Server) enforceSessionCapLocked() {
+	for len(s.sessions) >= maxLiveSessions {
+		var oldestID string
+		var oldest time.Time
+		found := false
+		for id, sess := range s.sessions {
+			if sess == nil {
+				delete(s.sessions, id)
+				continue
+			}
+			at := sess.LastAccessed()
+			if !found || at.Before(oldest) {
+				found = true
+				oldest = at
+				oldestID = id
+			}
+		}
+		if !found || oldestID == "" {
+			return
+		}
+		delete(s.sessions, oldestID)
+	}
+}
+
 // getOrCreateSession 获取或动态构建会话。callerUserID>0 时校验持久层归属，不匹配返回 ErrSessionOwnerMismatch。
 func (s *Server) getOrCreateSession(
 	ctx context.Context,
@@ -456,10 +482,12 @@ func (s *Server) getOrCreateSession(
 		return existing, nil
 	}
 
-	// 惰性内存防泄漏保护 (会话数超过 200 时清理空闲超 120 分钟会话)
+	// 惰性清理，并在仍超过硬上限时按最近访问淘汰，避免随机 session id 撑爆内存。
+	// 会话 id 仍由客户端提供：历史恢复按该 id 查找，不能改成只接受服务端签发。
 	if len(s.sessions) > 200 {
 		s.cleanStaleSessionsLocked(120 * time.Minute)
 	}
+	s.enforceSessionCapLocked()
 
 	// 尝试从持久层恢复会话上下文 (服务重启后跨进程保持 G3)
 	var restored *ctxmgr.RestoredSessionContext
diff --git a/internal/server/session_cap_test.go b/internal/server/session_cap_test.go
new file mode 100644
index 00000000..552b4246
--- /dev/null
+++ b/internal/server/session_cap_test.go
@@ -0,0 +1,33 @@
+package server
+
+import (
+	"fmt"
+	"testing"
+	"time"
+
+	"chat-agent-system/internal/chat"
+)
+
+func TestEnforceSessionCapEvictsOldest(t *testing.T) {
+	s := &Server{sessions: map[string]*chat.Session{}}
+	oldest := chat.NewSession("oldest", nil, nil, nil)
+	oldest.TouchLastAccessed()
+	s.sessions[oldest.ID] = oldest
+	time.Sleep(5 * time.Millisecond)
+	for i := 0; i < maxLiveSessions-1; i++ {
+		id := fmt.Sprintf("s%d", i)
+		sess := chat.NewSession(id, nil, nil, nil)
+		sess.TouchLastAccessed()
+		s.sessions[id] = sess
+	}
+	if len(s.sessions) != maxLiveSessions {
+		t.Fatalf("setup len=%d", len(s.sessions))
+	}
+	s.enforceSessionCapLocked()
+	if _, ok := s.sessions["oldest"]; ok {
+		t.Fatal("oldest session must be evicted at the cap")
+	}
+	if len(s.sessions) != maxLiveSessions-1 {
+		t.Fatalf("len=%d", len(s.sessions))
+	}
+}