diff --git a/internal/app/app.go b/internal/app/app.go
index cc6db91..9598eb9 100644
--- a/internal/app/app.go
+++ b/internal/app/app.go
@@ -112,6 +112,17 @@ func Run(opt Options) error {
 	}
 	setSvc := settings.NewService(st)
 	setSvc.SetSystemOverride(map[string]any{"storage": map[string]any{"dataDir": opt.DataDir}})
+	// 点路径键展开必须在读 tools.tavily.apiKeys 之前，否则启动仍注册旧池。
+	norm, err := setSvc.NormalizeStored()
+	if err != nil {
+		return fmt.Errorf("normalize settings: %w", err)
+	}
+	for _, p := range norm.MaskPaths {
+		log.Printf("settings: warning: stored value is the mask placeholder at %s", p)
+	}
+	if norm.DottedKeys > 0 {
+		log.Printf("settings: normalized %d dotted key(s) in %d scope(s)", norm.DottedKeys, norm.Scopes)
+	}
 	// 网络搜索（Tavily）：配置密钥池才注册（对齐 agent-native 语义：未配置不静默降级）。
 	eff := setSvc.Effective(store.OwnerDefault, "")
 	if keys := splitKeyPool(eff.GetString("tools.tavily.apiKeys", "")); len(keys) > 0 {
diff --git a/internal/server/e2e_test.go b/internal/server/e2e_test.go
index 0104371..2f3eb2e 100644
--- a/internal/server/e2e_test.go
+++ b/internal/server/e2e_test.go
@@ -1133,3 +1133,69 @@ func TestProjectInbox(t *testing.T) {
 		t.Errorf("unknown project subscribe should not leak, got %d", codeX)
 	}
 }
+
+// TestSettingsDottedKeyAndSecretMask：点路径写入生效、嵌套胜出、掩码不回写、GET 不回明文。
+func TestSettingsDottedKeyAndSecretMask(t *testing.T) {
+	srv, st := newTestServer(t)
+	h := srv.Handler()
+	set := func(body map[string]any) {
+		t.Helper()
+		code, out := doJSON(t, h, "PUT", "/api/settings/user", body)
+		if code != 200 {
+			t.Fatalf("PUT: %d %v", code, out)
+		}
+	}
+	svc := settings.NewService(st)
+
+	set(map[string]any{"runtime.entry": "squad"})
+	if got := svc.Effective(store.OwnerDefault, "").GetString("runtime.entry", ""); got != "squad" {
+		t.Fatalf("dotted write did not take effect: %q", got)
+	}
+	raw, err := svc.UserScope(store.OwnerDefault)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if _, ok := raw["runtime.entry"]; ok {
+		t.Fatalf("dotted key stored as-is: %#v", raw)
+	}
+
+	const pool = "tvly-should-not-leak"
+	const modelKey = "sk-should-not-leak"
+	set(map[string]any{"tools": map[string]any{"tavily": map[string]any{"apiKeys": pool}}})
+	set(map[string]any{"models": map[string]any{"chat": map[string]any{"apiKey": modelKey}}})
+	set(map[string]any{"models": map[string]any{"chat": map[string]any{"apiKey": settings.MaskPlaceholder}}})
+	set(map[string]any{
+		"tools":                map[string]any{"tavily": map[string]any{"apiKeys": "nested-wins"}},
+		"tools.tavily.apiKeys": "flat-loses",
+	})
+	eff := svc.Effective(store.OwnerDefault, "")
+	if got := eff.GetString("models.chat.apiKey", ""); got != modelKey {
+		t.Fatalf("mask writeback overwrote key: %q", got)
+	}
+	if got := eff.GetString("tools.tavily.apiKeys", ""); got != "nested-wins" {
+		t.Fatalf("nested form should win, got %q", got)
+	}
+
+	code, out := doJSON(t, h, "GET", "/api/settings", nil)
+	if code != 200 {
+		t.Fatalf("GET settings: %d", code)
+	}
+	blob, err := json.Marshal(out)
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, secret := range []string{pool, modelKey, "nested-wins", "flat-loses"} {
+		if strings.Contains(string(blob), secret) {
+			t.Fatalf("GET leaked %q", secret)
+		}
+	}
+	user := out["user"].(map[string]any)
+	tavily := user["tools"].(map[string]any)["tavily"].(map[string]any)
+	if tavily["apiKeys"] != settings.MaskPlaceholder {
+		t.Fatalf("apiKeys mask = %v", tavily["apiKeys"])
+	}
+	chat := user["models"].(map[string]any)["chat"].(map[string]any)
+	if chat["apiKey"] != settings.MaskPlaceholder {
+		t.Fatalf("apiKey mask = %v", chat["apiKey"])
+	}
+}
diff --git a/internal/server/server.go b/internal/server/server.go
index a06fb36..616fc90 100644
--- a/internal/server/server.go
+++ b/internal/server/server.go
@@ -1091,9 +1091,9 @@ func (s *Server) getSettings(w http.ResponseWriter, r *http.Request) {
 	schema := append(settings.Schema(), s.plugins.SettingsSchema()...)
 	writeJSON(w, http.StatusOK, map[string]any{
 		"schema":   schema,
-		"defaults": settings.Masked(core.EffectiveSettings(settings.SystemDefaults())),
-		"user":     maskMap(mustUser(s.set, owner)),
-		"project":  maskMap(mustScope(s.set, owner, projectID)),
+		"defaults": settings.Masked(settings.SystemDefaults(), schema),
+		"user":     settings.Masked(mustUser(s.set, owner), schema),
+		"project":  settings.Masked(mustScope(s.set, owner, projectID), schema),
 	})
 }
 
@@ -1486,13 +1486,6 @@ func asciiFallbackName(name string) string {
 	return b.String()
 }
 
-func maskMap(m map[string]any) map[string]any {
-	if m == nil {
-		return map[string]any{}
-	}
-	return settings.Masked(m)
-}
-
 func orEmptySlice[T any](s []T) []T {
 	if s == nil {
 		return []T{}
diff --git a/internal/settings/settings.go b/internal/settings/settings.go
index 6dfcb91..e53c128 100644
--- a/internal/settings/settings.go
+++ b/internal/settings/settings.go
@@ -3,6 +3,9 @@
 package settings
 
 import (
+	"sort"
+	"strings"
+
 	"agent-system-backend/internal/store"
 	core "agent-system-core"
 )
@@ -142,19 +145,77 @@ func (s *Service) ProjectScope(owner, projectID string) (map[string]any, error)
 }
 
 func (s *Service) MergeUser(owner string, values map[string]any) error {
-	return s.st.MergeSettingsScope(owner, ScopeUser, values)
+	return s.mergeScope(owner, ScopeUser, values)
 }
 
 func (s *Service) MergeProject(owner, projectID string, values map[string]any) error {
-	return s.st.MergeSettingsScope(owner, ScopeProjectPrefix+projectID, values)
+	return s.mergeScope(owner, ScopeProjectPrefix+projectID, values)
 }
 
-// Masked 返回脱敏视图（secret 类 key 掩码），用于 API 响应。Effective 每次
-// 深合并产出新 map，就地掩码不影响后续计算。
-func Masked(eff core.EffectiveSettings) map[string]any {
-	out := map[string]any(eff)
-	maskSecrets(out)
-	return out
+// mergeScope 先把库里和本次写入的点路径键展开成嵌套，再深合并。
+// 掩码占位符视为未修改，不覆盖已存密钥。
+func (s *Service) mergeScope(owner, scope string, values map[string]any) error {
+	incoming := prepareWrite(values)
+	return s.st.UpdateSettingsScope(owner, scope, func(cur map[string]any) (map[string]any, error) {
+		return core.MergeSettings(normalizeKeys(cur), incoming), nil
+	})
+}
+
+// NormalizeStats 是启动迁移的结果。MaskPaths 只含 owner、scope 和键路径，不含值。
+type NormalizeStats struct {
+	DottedKeys int
+	Scopes     int
+	MaskPaths  []string
+}
+
+// NormalizeStored 把已落库的点路径键展开成嵌套。嵌套对象胜出，已生效的值不变。
+// 存量值恰好是掩码占位符时记入 MaskPaths，原值保留（密钥已无法恢复）。
+func (s *Service) NormalizeStored() (NormalizeStats, error) {
+	var stats NormalizeStats
+	refs, err := s.st.ListSettingsScopes()
+	if err != nil {
+		return stats, err
+	}
+	for _, ref := range refs {
+		var dotted int
+		var masks []string
+		err := s.st.UpdateSettingsScope(ref.Owner, ref.Scope, func(cur map[string]any) (map[string]any, error) {
+			dotted = countDottedKeys(cur)
+			next := normalizeKeys(cur)
+			for _, p := range maskPlaceholderPaths(next, "") {
+				masks = append(masks, ref.Owner+" "+ref.Scope+" "+p)
+			}
+			return next, nil
+		})
+		if err != nil {
+			return stats, err
+		}
+		stats.MaskPaths = append(stats.MaskPaths, masks...)
+		if dotted > 0 {
+			stats.DottedKeys += dotted
+			stats.Scopes++
+		}
+	}
+	return stats, nil
+}
+
+// MaskPlaceholder 是 GET 对密钥的掩码。写回这个值视为未修改。
+const MaskPlaceholder = "••••••"
+
+// Masked 返回脱敏视图。schema 中 Type=secret 或 Secret=true 的路径一律掩码；
+// 叶子键名（apiKey/apiKeys 等）再兜底一层，覆盖 schema 未声明的密钥。
+// 就地掩码：调用方须传入可丢弃的 map（Effective 每次深合并产出新 map）。
+func Masked(values map[string]any, schema []core.SettingDesc) map[string]any {
+	if values == nil {
+		return map[string]any{}
+	}
+	maskSecrets(values)
+	for _, d := range schema {
+		if d.Type == core.SettingSecret || d.Secret {
+			maskAtPath(values, d.Key)
+		}
+	}
+	return values
 }
 
 func maskSecrets(m map[string]any) {
@@ -165,12 +226,136 @@ func maskSecrets(m map[string]any) {
 		}
 		if isSecretKey(k) {
 			if s, ok := v.(string); ok && s != "" {
-				m[k] = "••••••"
+				m[k] = MaskPlaceholder
 			}
 		}
 	}
 }
 
 func isSecretKey(k string) bool {
-	return k == "apiKey" || k == "api_key" || k == "secret" || k == "token"
+	switch k {
+	case "apiKey", "api_key", "apiKeys", "secret", "token":
+		return true
+	default:
+		return false
+	}
+}
+
+// prepareWrite 丢弃掩码占位符，再把点路径键展开成嵌套。
+func prepareWrite(values map[string]any) map[string]any {
+	return normalizeKeys(dropMaskPlaceholders(values))
+}
+
+// normalizeKeys 递归展开点路径键。同一层嵌套对象与点路径冲突时嵌套胜出；
+// 点路径键按字典序依次合并，后写入的覆盖先写入的。不改入参。
+func normalizeKeys(in map[string]any) map[string]any {
+	if len(in) == 0 {
+		return map[string]any{}
+	}
+	plain := make(map[string]any, len(in))
+	dotted := make([]string, 0)
+	for k, v := range in {
+		if strings.Contains(k, ".") {
+			dotted = append(dotted, k)
+			continue
+		}
+		plain[k] = normalizeValue(v)
+	}
+	sort.Strings(dotted)
+	expanded := map[string]any{}
+	for _, k := range dotted {
+		expanded = core.MergeSettings(expanded, expandDotted(k, normalizeValue(in[k])))
+	}
+	return core.MergeSettings(expanded, plain)
+}
+
+func normalizeValue(v any) any {
+	vm, ok := v.(map[string]any)
+	if !ok {
+		return v
+	}
+	return normalizeKeys(vm)
+}
+
+// expandDotted 把 "a.b.c" 收成 {a:{b:{c: val}}}。
+func expandDotted(key string, val any) map[string]any {
+	parts := strings.Split(key, ".")
+	built := val
+	for i := len(parts) - 1; i >= 0; i-- {
+		built = map[string]any{parts[i]: built}
+	}
+	return built.(map[string]any)
+}
+
+func dropMaskPlaceholders(m map[string]any) map[string]any {
+	out := make(map[string]any, len(m))
+	for k, v := range m {
+		if vm, ok := v.(map[string]any); ok {
+			out[k] = dropMaskPlaceholders(vm)
+			continue
+		}
+		if s, ok := v.(string); ok && s == MaskPlaceholder {
+			continue
+		}
+		out[k] = v
+	}
+	return out
+}
+
+func countDottedKeys(m map[string]any) int {
+	n := 0
+	for k, v := range m {
+		if strings.Contains(k, ".") {
+			n++
+		}
+		if vm, ok := v.(map[string]any); ok {
+			n += countDottedKeys(vm)
+		}
+	}
+	return n
+}
+
+func maskPlaceholderPaths(m map[string]any, prefix string) []string {
+	var out []string
+	for k, v := range m {
+		path := k
+		if prefix != "" {
+			path = prefix + "." + k
+		}
+		if vm, ok := v.(map[string]any); ok {
+			out = append(out, maskPlaceholderPaths(vm, path)...)
+			continue
+		}
+		if s, ok := v.(string); ok && s == MaskPlaceholder {
+			out = append(out, path)
+		}
+	}
+	sort.Strings(out)
+	return out
+}
+
+// maskAtPath 掩码 schema 路径。路径作为单个点键存在时同样掩码。
+func maskAtPath(m map[string]any, path string) {
+	if s, ok := m[path].(string); ok && s != "" {
+		m[path] = MaskPlaceholder
+	}
+	parts := strings.Split(path, ".")
+	cur := m
+	for i, p := range parts {
+		v, ok := cur[p]
+		if !ok {
+			return
+		}
+		if i == len(parts)-1 {
+			if s, ok := v.(string); ok && s != "" {
+				cur[p] = MaskPlaceholder
+			}
+			return
+		}
+		next, ok := v.(map[string]any)
+		if !ok {
+			return
+		}
+		cur = next
+	}
 }
diff --git a/internal/settings/settings_test.go b/internal/settings/settings_test.go
index 50a52a7..2fd2a20 100644
--- a/internal/settings/settings_test.go
+++ b/internal/settings/settings_test.go
@@ -1,6 +1,14 @@
 package settings
 
-import "testing"
+import (
+	"path/filepath"
+	"reflect"
+	"strings"
+	"testing"
+
+	"agent-system-backend/internal/store"
+	core "agent-system-core"
+)
 
 func TestLLMRetriesDefault(t *testing.T) {
 	block := SystemDefaults()["runtime"].(map[string]any)
@@ -39,3 +47,185 @@ func TestDeliverableSettingsPresent(t *testing.T) {
 		t.Fatalf("schema missing deliverable keys: style=%v accent=%v template=%v", style, accent, template)
 	}
 }
+
+func TestNormalizeKeys(t *testing.T) {
+	cases := []struct {
+		name string
+		in   map[string]any
+		want map[string]any
+	}{
+		{
+			name: "dotted only",
+			in:   map[string]any{"runtime.entry": "squad"},
+			want: map[string]any{"runtime": map[string]any{"entry": "squad"}},
+		},
+		{
+			name: "nested wins over dotted",
+			in: map[string]any{
+				"tools":                map[string]any{"tavily": map[string]any{"apiKeys": "nested"}},
+				"tools.tavily.apiKeys": "flat",
+			},
+			want: map[string]any{"tools": map[string]any{"tavily": map[string]any{"apiKeys": "nested"}}},
+		},
+		{
+			name: "dotted key inside a nested object",
+			in:   map[string]any{"tools": map[string]any{"tavily.apiKeys": "x"}},
+			want: map[string]any{"tools": map[string]any{"tavily": map[string]any{"apiKeys": "x"}}},
+		},
+		{
+			name: "overlapping dotted keys merge in lexicographic order",
+			in:   map[string]any{"a.b": 1, "a.b.c": 2, "a.c": 3},
+			want: map[string]any{"a": map[string]any{"b": map[string]any{"c": 2}, "c": 3}},
+		},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			got := normalizeKeys(tc.in)
+			if !reflect.DeepEqual(got, tc.want) {
+				t.Fatalf("got %#v\nwant %#v", got, tc.want)
+			}
+		})
+	}
+	in := map[string]any{"runtime.entry": "squad"}
+	_ = normalizeKeys(in)
+	if _, ok := in["runtime.entry"]; !ok {
+		t.Fatal("normalizeKeys mutated its input")
+	}
+}
+
+func TestPrepareWriteDropsMask(t *testing.T) {
+	got := prepareWrite(map[string]any{
+		"models":        map[string]any{"chat": map[string]any{"apiKey": MaskPlaceholder, "model": "m"}},
+		"runtime.entry": "squad",
+	})
+	want := map[string]any{
+		"models":  map[string]any{"chat": map[string]any{"model": "m"}},
+		"runtime": map[string]any{"entry": "squad"},
+	}
+	if !reflect.DeepEqual(got, want) {
+		t.Fatalf("got %#v", got)
+	}
+}
+
+func TestMaskedBySchemaAndLeafName(t *testing.T) {
+	values := map[string]any{
+		"tools":                map[string]any{"tavily": map[string]any{"apiKeys": "tvly-secret"}},
+		"models":               map[string]any{"chat": map[string]any{"apiKey": "sk-secret"}},
+		"plugins":              map[string]any{"example": map[string]any{"token": "plugin-secret"}},
+		"custom":               map[string]any{"apiKeys": "pool-secret"},
+		"tools.tavily.apiKeys": "flat-secret",
+	}
+	schema := []core.SettingDesc{
+		{Key: "tools.tavily.apiKeys", Type: core.SettingSecret},
+		{Key: "models.chat.apiKey", Type: core.SettingSecret},
+		{Key: "plugins.example.token", Type: core.SettingString, Secret: true},
+	}
+	out := Masked(values, schema)
+	blob := stringify(out)
+	for _, secret := range []string{"tvly-secret", "sk-secret", "plugin-secret", "pool-secret", "flat-secret"} {
+		if strings.Contains(blob, secret) {
+			t.Fatalf("secret %q leaked: %#v", secret, out)
+		}
+	}
+	if out["tools"].(map[string]any)["tavily"].(map[string]any)["apiKeys"] != MaskPlaceholder {
+		t.Fatal("tavily apiKeys not masked")
+	}
+	if out["plugins"].(map[string]any)["example"].(map[string]any)["token"] != MaskPlaceholder {
+		t.Fatal("plugin token not masked")
+	}
+	if out["tools.tavily.apiKeys"] != MaskPlaceholder {
+		t.Fatal("flat secret key not masked")
+	}
+}
+
+func TestMergeUserDottedKeyMaskAndNormalizeStored(t *testing.T) {
+	st, err := store.OpenSQLite(filepath.Join(t.TempDir(), "t.db"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { st.Close() })
+	svc := NewService(st)
+
+	if err := st.MergeSettingsScope("local", ScopeUser, map[string]any{
+		"runtime.entry":        "squad",
+		"tools":                map[string]any{"tavily": map[string]any{"apiKeys": "nested"}},
+		"tools.tavily.apiKeys": "flat",
+		"models":               map[string]any{"chat": map[string]any{"apiKey": MaskPlaceholder}},
+	}); err != nil {
+		t.Fatal(err)
+	}
+	if err := st.MergeSettingsScope("local", ScopeProjectPrefix+"p1", map[string]any{
+		"context.maxHistoryMessages": 30,
+	}); err != nil {
+		t.Fatal(err)
+	}
+
+	stats, err := svc.NormalizeStored()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if stats.DottedKeys != 3 || stats.Scopes != 2 {
+		t.Fatalf("stats = %+v", stats)
+	}
+	foundMask := false
+	for _, p := range stats.MaskPaths {
+		if p == "local user models.chat.apiKey" {
+			foundMask = true
+		}
+	}
+	if !foundMask {
+		t.Fatalf("mask path missing: %v", stats.MaskPaths)
+	}
+	eff := svc.Effective("local", "p1")
+	if eff.GetString("runtime.entry", "") != "squad" {
+		t.Fatalf("entry = %q", eff.GetString("runtime.entry", ""))
+	}
+	if eff.GetString("tools.tavily.apiKeys", "") != "nested" {
+		t.Fatalf("nested key lost: %q", eff.GetString("tools.tavily.apiKeys", ""))
+	}
+	if eff.GetNumber("context.maxHistoryMessages", 0) != 30 {
+		t.Fatalf("history = %v", eff.GetNumber("context.maxHistoryMessages", 0))
+	}
+	again, err := svc.NormalizeStored()
+	if err != nil || again.DottedKeys != 0 {
+		t.Fatalf("second pass = %+v err=%v", again, err)
+	}
+
+	if err := svc.MergeUser("local", map[string]any{"runtime.entry": "direct"}); err != nil {
+		t.Fatal(err)
+	}
+	if svc.Effective("local", "").GetString("runtime.entry", "") != "direct" {
+		t.Fatal("dotted write did not take effect")
+	}
+	raw, err := svc.UserScope("local")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if _, ok := raw["runtime.entry"]; ok {
+		t.Fatalf("dotted key persisted: %#v", raw)
+	}
+	if err := svc.MergeUser("local", map[string]any{"models": map[string]any{"chat": map[string]any{"apiKey": "sk-real"}}}); err != nil {
+		t.Fatal(err)
+	}
+	if err := svc.MergeUser("local", map[string]any{"models.chat.apiKey": MaskPlaceholder}); err != nil {
+		t.Fatal(err)
+	}
+	if got := svc.Effective("local", "").GetString("models.chat.apiKey", ""); got != "sk-real" {
+		t.Fatalf("mask writeback overwrote key: %q", got)
+	}
+}
+
+func stringify(v any) string {
+	switch x := v.(type) {
+	case string:
+		return x
+	case map[string]any:
+		out := ""
+		for k, val := range x {
+			out += k + "=" + stringify(val) + ";"
+		}
+		return out
+	default:
+		return ""
+	}
+}
diff --git a/internal/store/config.go b/internal/store/config.go
index 76a040a..47f6b19 100644
--- a/internal/store/config.go
+++ b/internal/store/config.go
@@ -84,8 +84,33 @@ func (s *Store) GetSettingsScope(owner, scope string) (map[string]any, error) {
 	return out, nil
 }
 
-// MergeSettingsScope 读改写走事务 + scope 锁：并发合并不再丢失更新。
-func (s *Store) MergeSettingsScope(owner, scope string, values map[string]any) error {
+// SettingsScopeRef 标识一行设置（owner + scope），不含值。
+type SettingsScopeRef struct {
+	Owner string
+	Scope string
+}
+
+// ListSettingsScopes 返回全部已落库的 scope，供启动迁移遍历。
+func (s *Store) ListSettingsScopes() ([]SettingsScopeRef, error) {
+	rows, err := s.db.Query(s.q(`SELECT owner, scope FROM settings ORDER BY owner, scope`))
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	out := []SettingsScopeRef{}
+	for rows.Next() {
+		var ref SettingsScopeRef
+		if err := rows.Scan(&ref.Owner, &ref.Scope); err != nil {
+			return nil, err
+		}
+		out = append(out, ref)
+	}
+	return out, rows.Err()
+}
+
+// UpdateSettingsScope 在事务和 scope 锁内读改写。fn 返回的 map 与当前值
+// JSON 相同时不写库。并发合并不再丢失更新。
+func (s *Store) UpdateSettingsScope(owner, scope string, fn func(cur map[string]any) (map[string]any, error)) error {
 	tx, err := s.db.Begin()
 	if err != nil {
 		return err
@@ -102,16 +127,35 @@ func (s *Store) MergeSettingsScope(owner, scope string, values map[string]any) e
 	cur := map[string]any{}
 	if payload != "" {
 		cur, _ = unmarshalJSON[map[string]any](payload)
+		if cur == nil {
+			cur = map[string]any{}
+		}
+	}
+	next, err := fn(cur)
+	if err != nil {
+		return err
+	}
+	if next == nil {
+		next = map[string]any{}
+	}
+	if marshalJSON(cur) == marshalJSON(next) {
+		return tx.Commit()
 	}
-	merged := core.MergeSettings(cur, values)
 	_, err = tx.Exec(s.q(`INSERT INTO settings(owner,scope,"values") VALUES(?,?,?)
-		ON CONFLICT(owner,scope) DO UPDATE SET "values"=excluded."values"`), owner, scope, marshalJSON(merged))
+		ON CONFLICT(owner,scope) DO UPDATE SET "values"=excluded."values"`), owner, scope, marshalJSON(next))
 	if err != nil {
 		return err
 	}
 	return tx.Commit()
 }
 
+// MergeSettingsScope 读改写走事务 + scope 锁：并发合并不再丢失更新。
+func (s *Store) MergeSettingsScope(owner, scope string, values map[string]any) error {
+	return s.UpdateSettingsScope(owner, scope, func(cur map[string]any) (map[string]any, error) {
+		return core.MergeSettings(cur, values), nil
+	})
+}
+
 func (s *Store) DeleteSettingsScope(owner, scope string) error {
 	_, err := s.db.Exec(s.q(`DELETE FROM settings WHERE owner=? AND scope=?`), owner, scope)
 	return err