diff --git a/db/db.go b/db/db.go
index 6a35129..de0a738 100644
--- a/db/db.go
+++ b/db/db.go
@@ -117,7 +117,8 @@ func intp(v int) *int { return &v }
 var builtinAgents = []builtinAgent{
 	{"goals", "目标拆解", "goals", "把渗透任务目标拆解成若干独立、可验证的子目标。", []promptVar{
 		{"EngagementDescription", "任务描述（测试对象/背景）", "测试 example.com 站点", "exploration"},
-		{"Now", "服务端当前时间(RFC3339)", "2026-06-25T00:00:00Z", "runtime"},
+		// Now 是全局 runtime 变量(见 server.globalPromptVars),不再在各 agent 目录里
+		// 重复定义,否则 withGlobalVars 追加时会与全局项撞名。
 	}, false, nil},
 	{"planner", "规划", "planner", "读取态势、判定目标，只在确有未覆盖的新方向时补充探索意图（每任务一个规划循环）。", []promptVar{
 		{"Goal", "任务总目标", "拿下 example.com 的管理员权限", "exploration"},
@@ -163,7 +164,9 @@ ON CONFLICT (agent_id, var_name) DO UPDATE
 	}
 	// Drop catalog entries for variables that were renamed, so the white-list no
 	// longer advertises a name templates can't resolve (EngagementTitle→Description).
-	if _, err := d.Exec(`DELETE FROM agent_prompt_vars WHERE var_name IN ('EngagementTitle', 'CoverageGaps')`); err != nil {
+	// 'Now' 从各 agent 目录提升为全局 runtime 变量后,旧库里 goals 仍残留一条 'Now'
+	// 会与全局项撞名(前端变量列表 key 重复);一并清掉。
+	if _, err := d.Exec(`DELETE FROM agent_prompt_vars WHERE var_name IN ('EngagementTitle', 'CoverageGaps', 'Now')`); err != nil {
 		return fmt.Errorf("cleanup renamed vars: %w", err)
 	}
 	// Default-on interactive_shell for the runtime agents (planner/worker/mainagent/auto)
diff --git a/server/prompt_vars_test.go b/server/prompt_vars_test.go
new file mode 100644
index 0000000..1ab9eae
--- /dev/null
+++ b/server/prompt_vars_test.go
@@ -0,0 +1,58 @@
+package server
+
+import (
+	"testing"
+
+	"github.com/Autumn-27/artex/db"
+)
+
+// A stored catalog entry that collides with a global runtime var (e.g. a legacy
+// seeded goals."Now") must not produce a duplicate: the global wins and the name
+// appears exactly once, so the UI never sees duplicate React keys.
+func TestWithGlobalVarsDedupesCollidingNames(t *testing.T) {
+	t.Parallel()
+	stored := []db.PromptVar{
+		{Name: "EngagementDescription", Description: "task", Source: "exploration"},
+		{Name: "Now", Description: "stale per-agent copy", Source: "runtime"},
+	}
+	out := withGlobalVars(stored)
+
+	counts := map[string]int{}
+	var now db.PromptVar
+	for _, v := range out {
+		counts[v.Name]++
+		if v.Name == "Now" {
+			now = v
+		}
+	}
+	if counts["Now"] != 1 {
+		t.Fatalf("Now appeared %d times, want 1: %+v", counts["Now"], out)
+	}
+	if counts["EngagementDescription"] != 1 {
+		t.Fatalf("non-colliding stored var was dropped or duplicated: %+v", out)
+	}
+	// The surviving Now must be the authoritative global definition, not the stale
+	// stored one.
+	if now.Description == "stale per-agent copy" {
+		t.Fatalf("stored var shadowed the global instead of the other way around: %+v", now)
+	}
+	// Every global is present exactly once.
+	for _, g := range globalPromptVars {
+		if counts[g.Name] != 1 {
+			t.Fatalf("global %q present %d times, want 1", g.Name, counts[g.Name])
+		}
+	}
+}
+
+// The common case (no collisions) keeps every stored var and appends all globals.
+func TestWithGlobalVarsKeepsDistinctVars(t *testing.T) {
+	t.Parallel()
+	stored := []db.PromptVar{{Name: "Goal", Source: "exploration"}}
+	out := withGlobalVars(stored)
+	if len(out) != len(stored)+len(globalPromptVars) {
+		t.Fatalf("len=%d, want %d: %+v", len(out), len(stored)+len(globalPromptVars), out)
+	}
+	if out[0].Name != "Goal" {
+		t.Fatalf("stored var order not preserved: %+v", out)
+	}
+}
diff --git a/server/server_mgmt.go b/server/server_mgmt.go
index 49c0998..fbe2179 100644
--- a/server/server_mgmt.go
+++ b/server/server_mgmt.go
@@ -2008,8 +2008,22 @@ var globalPromptVars = []db.PromptVar{
 
 // withGlobalVars appends the universal runtime vars onto an agent's own catalog,
 // so validation / the UI variable list / preview all recognize {{.Now}} etc.
+// A stored catalog entry that collides with a global name is dropped: the global
+// runtime var is authoritative (it's what the render path actually resolves), and
+// this keeps the returned list name-unique so the UI never sees duplicate keys.
 func withGlobalVars(vars []db.PromptVar) []db.PromptVar {
-	return append(append([]db.PromptVar{}, vars...), globalPromptVars...)
+	globalNames := make(map[string]bool, len(globalPromptVars))
+	for _, g := range globalPromptVars {
+		globalNames[g.Name] = true
+	}
+	out := make([]db.PromptVar, 0, len(vars)+len(globalPromptVars))
+	for _, v := range vars {
+		if globalNames[v.Name] {
+			continue // shadowed by the authoritative global runtime var
+		}
+		out = append(out, v)
+	}
+	return append(out, globalPromptVars...)
 }
 
 // validateTemplate parses the template and rejects any {{.Var}} not in the catalog.