diff --git a/scripts/ci/pingora_edge_policy.py b/scripts/ci/pingora_edge_policy.py
index 648bfd064b..06694fcbca 100644
--- a/scripts/ci/pingora_edge_policy.py
+++ b/scripts/ci/pingora_edge_policy.py
@@ -342,7 +342,20 @@ def _load_changed_files(api_url: str, repository: str, pull_request: int, token:
                 raise PolicyError("GitHub changed-file pagination exceeded 3,000 files")
         if len(payload) < 100:
             return tuple(files)
-    raise PolicyError("GitHub changed-file pagination exceeded 3,000 files")
+    # Unreachable by construction, not a live fallback: every one of the 31
+    # `range(1, 32)` iterations that reaches this point already returned a
+    # page whose length is >= 100 (a page under 100 items hits the `return`
+    # two lines up first), so 31 such pages accumulate at least 3,100 files
+    # -- strictly more than the 3,000 cap above, which is checked after
+    # every single appended item, not just at page boundaries. That in-loop
+    # check therefore always raises no later than partway through the 31st
+    # page, before the `for` loop can ever exhaust its range. Kept as a
+    # structural fail-closed guard (so a future change to PAGE_COUNT,
+    # per_page, or the 3,000 cap that breaks this invariant fails loudly
+    # instead of silently truncating evidence) rather than deleted; see
+    # test_changed_file_pagination_bound_is_provably_unreachable, which
+    # pins the arithmetic relationship itself.
+    raise PolicyError("GitHub changed-file pagination exceeded 3,000 files")  # pragma: no cover
 
 
 def _load_raw_file_bytes(api_url: str, repository: str, path: str, head_sha: str, token: str, opener: OpenJson) -> bytes:
diff --git a/tests/test_pingora_edge_policy.py b/tests/test_pingora_edge_policy.py
index 26434207cb..70bb1bc970 100644
--- a/tests/test_pingora_edge_policy.py
+++ b/tests/test_pingora_edge_policy.py
@@ -4,6 +4,8 @@
 
 import base64
 import importlib.util
+import inspect
+import re
 import sys
 from io import BytesIO
 from pathlib import Path
@@ -491,6 +493,35 @@ def opener(url: str, _token: str) -> object:
     assert calls[-1].endswith("page=31")
 
 
+def test_changed_file_pagination_bound_is_provably_unreachable() -> None:
+    """Pin the arithmetic invariant that makes the loop's trailing raise dead code.
+
+    ``_load_changed_files`` raises inside its item loop the moment
+    ``len(files) > 3_000`` (checked after every appended item, not only at
+    page boundaries) and returns early the moment one page has fewer than
+    100 items -- so the ``# pragma: no cover``-marked ``raise`` after the
+    ``for page in range(...)`` loop can only execute if every one of that
+    many pages returns at least 100 items while the cumulative total never
+    exceeds 3,000. That requires ``page_count * per_page <= 3_000``, which
+    the real page count (31) and per_page (100) violate (3,100 > 3,000) --
+    the in-loop raise always fires first. This test reads those literals
+    from the actual source rather than duplicating them, so it fails loudly
+    if a future edit to any of the three breaks the inequality -- exactly
+    when the trailing raise becomes reachable again and needs a real
+    covering test instead of the pragma.
+    """
+    source = inspect.getsource(policy._load_changed_files)
+    start, stop = (int(n) for n in re.search(r"range\((\d+),\s*(\d+)\)", source).groups())
+    page_count = len(range(start, stop))
+    per_page = int(re.search(r"per_page=(\d+)", source).group(1))
+    cap = int(re.search(r"len\(files\) > (\d[\d_]*)", source).group(1).replace("_", ""))
+    assert page_count * per_page > cap, (
+        "the trailing pagination raise in _load_changed_files is no longer "
+        "provably unreachable; remove its '# pragma: no cover' and add a "
+        "test that actually covers it"
+    )
+
+
 @pytest.mark.parametrize(
     ("payload", "message"),
     [