diff --git a/evalharness/sandbox/prefetch.py b/evalharness/sandbox/prefetch.py
index 3e56fdb..586c577 100644
--- a/evalharness/sandbox/prefetch.py
+++ b/evalharness/sandbox/prefetch.py
@@ -115,7 +115,11 @@ def _pull_one(image: str, verbose: bool = True) -> None:
     for template in _CN_MIRROR_FALLBACKS:
         ref = template.format(img=image)
         if verbose:
-            src = 'docker.io(daemon mirrors)' if '{img}' in template else template.split('/{img}')[0]
+            # the daemon-default entry IS exactly '{img}'; every real
+            # mirror template also CONTAINS '{img}' -- the old containment
+            # check matched both and labeled everything docker.io
+            src = ('docker.io (daemon mirrors)' if template.strip() == '{img}'
+                   else template.split('/{img}')[0])
             print(f'· pulling sandbox image {image} via {src} ...',
                   file=_sys.stderr, flush=True)
         t0 = _time.monotonic()