diff --git a/internal/chat/service_template.go b/internal/chat/service_template.go
new file mode 100644
index 0000000..9bfa40b
--- /dev/null
+++ b/internal/chat/service_template.go
@@ -0,0 +1,109 @@
+package chat
+
+import (
+	"context"
+	"log/slog"
+	"time"
+
+	"github.com/google/uuid"
+
+	"github.com/yan1h/agent-coding-workflow/internal/audit"
+	"github.com/yan1h/agent-coding-workflow/internal/infra/errs"
+)
+
+type templateService struct {
+	repo    Repository
+	auditor audit.Recorder
+	log     *slog.Logger
+}
+
+var _ TemplateService = (*templateService)(nil)
+
+// NewTemplateService 构造 prompt_templates CRUD 服务。
+func NewTemplateService(repo Repository, a audit.Recorder, log *slog.Logger) TemplateService {
+	return &templateService{repo: repo, auditor: a, log: log}
+}
+
+func (s *templateService) List(ctx context.Context, userID uuid.UUID) ([]PromptTemplate, error) {
+	return s.repo.ListTemplatesForUser(ctx, userID)
+}
+
+func (s *templateService) Create(ctx context.Context, userID uuid.UUID, name, content string, scope TemplateScope) (*PromptTemplate, error) {
+	if scope != TemplateScopeSystem && scope != TemplateScopeUser {
+		return nil, errs.New(errs.CodeInvalidInput, "invalid scope")
+	}
+	t := &PromptTemplate{
+		ID:        uuid.Must(uuid.NewV7()),
+		Name:      name,
+		Content:   content,
+		Scope:     scope,
+		CreatedAt: time.Now(),
+		UpdatedAt: time.Now(),
+	}
+	if scope == TemplateScopeUser {
+		uid := userID
+		t.OwnerID = &uid
+	}
+	if err := s.repo.InsertTemplate(ctx, t); err != nil {
+		return nil, err
+	}
+	if scope == TemplateScopeSystem {
+		s.tryAudit(ctx, audit.Entry{
+			UserID: &userID, Action: "prompt_template.created",
+			TargetType: "prompt_template", TargetID: t.ID.String(),
+		})
+	}
+	return t, nil
+}
+
+func (s *templateService) Update(ctx context.Context, userID, id uuid.UUID, name, content string) error {
+	t, err := s.repo.GetTemplate(ctx, id)
+	if err != nil {
+		return err
+	}
+	if t == nil {
+		return errs.New(errs.CodeChatTemplateNotFound, "template not found")
+	}
+	if t.Scope == TemplateScopeUser && (t.OwnerID == nil || *t.OwnerID != userID) {
+		return errs.New(errs.CodeForbidden, "not template owner")
+	}
+	if err := s.repo.UpdateTemplate(ctx, id, name, content); err != nil {
+		return err
+	}
+	if t.Scope == TemplateScopeSystem {
+		s.tryAudit(ctx, audit.Entry{
+			UserID: &userID, Action: "prompt_template.updated",
+			TargetType: "prompt_template", TargetID: id.String(),
+		})
+	}
+	return nil
+}
+
+func (s *templateService) Delete(ctx context.Context, userID, id uuid.UUID) error {
+	t, err := s.repo.GetTemplate(ctx, id)
+	if err != nil {
+		return err
+	}
+	if t == nil {
+		return errs.New(errs.CodeChatTemplateNotFound, "template not found")
+	}
+	if t.Scope == TemplateScopeUser && (t.OwnerID == nil || *t.OwnerID != userID) {
+		return errs.New(errs.CodeForbidden, "not template owner")
+	}
+	if err := s.repo.DeleteTemplate(ctx, id); err != nil {
+		return err
+	}
+	if t.Scope == TemplateScopeSystem {
+		s.tryAudit(ctx, audit.Entry{
+			UserID: &userID, Action: "prompt_template.deleted",
+			TargetType: "prompt_template", TargetID: id.String(),
+		})
+	}
+	return nil
+}
+
+func (s *templateService) tryAudit(ctx context.Context, e audit.Entry) {
+	if err := s.auditor.Record(ctx, e); err != nil {
+		s.log.Warn("audit record failed", "action", e.Action, "err", err)
+	}
+}