diff --git a/internal/runtime/loop/loop_vision_test.go b/internal/runtime/loop/loop_vision_test.go
index e54067c..eebaae2 100644
--- a/internal/runtime/loop/loop_vision_test.go
+++ b/internal/runtime/loop/loop_vision_test.go
@@ -2,11 +2,46 @@ package loop
 
 import (
 	"context"
+	"errors"
+	"fmt"
 	"testing"
 
 	"git.yeij.top/AskaEth/Cyrene_v2/internal/runtime/model"
 )
 
+// fakeSourceErr 模拟 vision 包的 SourceFailure：错误链上能报出来源主机。
+type fakeSourceErr struct{ host string }
+
+func (e *fakeSourceErr) Error() string { return "取回失败" }
+func (e *fakeSourceErr) ImageSourceHost() string {
+	return e.host
+}
+
+// TestImageSourceHost 钉住「日志能定位到来源主机」这条契约：错误链上
+// 带 ImageSourceHost 的证据要穿透 %w 包装被取出；其它错误一律空串
+// （空串表示无从定位，而不是假装有来源）。
+func TestImageSourceHost(t *testing.T) {
+	t.Parallel()
+	cases := []struct {
+		name string
+		err  error
+		want string
+	}{
+		{name: "nil 错误", err: nil, want: ""},
+		{name: "普通错误", err: errors.New("解析失败"), want: ""},
+		{name: "包装后的来源错误", err: fmt.Errorf("resolve: %w", &fakeSourceErr{host: "cdn.example.com"}), want: "cdn.example.com"},
+		{name: "包装但主机为空", err: fmt.Errorf("resolve: %w", &fakeSourceErr{}), want: ""},
+	}
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			t.Parallel()
+			if got := imageSourceHost(c.err); got != c.want {
+				t.Fatalf("imageSourceHost = %q, want %q", got, c.want)
+			}
+		})
+	}
+}
+
 func TestRun_ImageResolverFoldsToText(t *testing.T) {
 	t.Parallel()
 	ad := &mockAdapter{chat: []mgResp{{resp: model.Response{Model: "m", Content: "Done."}}}}
diff --git a/internal/runtime/loop/vision.go b/internal/runtime/loop/vision.go
index 6fb04c7..bc5fb92 100644
--- a/internal/runtime/loop/vision.go
+++ b/internal/runtime/loop/vision.go
@@ -2,6 +2,7 @@ package loop
 
 import (
 	"context"
+	"errors"
 
 	"git.yeij.top/AskaEth/Cyrene_v2/internal/runtime/model"
 )
@@ -47,7 +48,10 @@ func (l *Loop) resolveImages(ctx context.Context, messages []model.Message) []mo
 		}
 		resolved, err := l.imageResolver.Resolve(ctx, m)
 		if err != nil {
-			l.log.Warn("image resolve", "error", err)
+			// 图像解析失败（尤其：URL 来源已失效）在这里留下可诊断信号 ——
+			// 原消息照旧保留、回合继续，但不再静默：host 是来源 URL 的主机，
+			// 不含路径、查询串与凭据（由 SourceFailure 保证）。
+			l.log.Warn("image resolve", "error", err, "host", imageSourceHost(err))
 			out[i] = m
 			continue
 		}
@@ -60,6 +64,18 @@ func (l *Loop) resolveImages(ctx context.Context, messages []model.Message) []mo
 	return out
 }
 
+// imageSourceHost 从图像解析失败错误里取出来源主机（vision 的取回失败
+// 错误以结构断言暴露它），使 WARN 能定位到具体来源。错误不带这个信息
+// （解析失败、非图像、无解析器等）时返回空串。用结构断言而不是导入
+// vision 包：loop 只需知道「有个东西能报主机」，不需要依赖取回实现。
+func imageSourceHost(err error) string {
+	var withHost interface{ ImageSourceHost() string }
+	if errors.As(err, &withHost) {
+		return withHost.ImageSourceHost()
+	}
+	return ""
+}
+
 // messageHasImage 报告 msg 是否有任何内容部件是图像部件。
 func messageHasImage(m model.Message) bool {
 	for _, part := range m.Content {