diff --git a/.github/workflows/snippets.yaml b/.github/workflows/snippets.yaml
index 6774896..cc6b001 100644
--- a/.github/workflows/snippets.yaml
+++ b/.github/workflows/snippets.yaml
@@ -39,6 +39,10 @@ jobs:
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
         with:
           persist-credentials: false
+      - name: Setup Python
+        uses: actions/setup-python@6d4fd22b20465ccc0f7354476588e8df7c9ca0e0 # v7.1.0
+        with:
+          python-version: "3.15"
       - name: Test the snippet checker
         run: python3 -m unittest discover -s scripts -p 'test_*.py'
       - name: Compare the guides with examples/
diff --git a/scripts/snippets.py b/scripts/snippets.py
index 31328b0..4c65636 100755
--- a/scripts/snippets.py
+++ b/scripts/snippets.py
@@ -102,7 +102,7 @@ def source(path: str, region: str | None) -> tuple[str | None, str]:
     file = ROOT / path
     if not file.is_file():
         return None, f"file not found: {path}"
-    text = file.read_text(encoding="utf-8")
+    text = file.read_text()
     if region is None:
         return text, ""
     body = region_text(text, region)
@@ -123,7 +123,7 @@ def fence_end(lines: list[str], start: int, fence: str) -> int:
 def process(page: Path, write: bool, shown: set[str]) -> list[str]:
     """Check or rewrite one page. Return its problems."""
     rel = page.relative_to(ROOT).as_posix()
-    lines = page.read_text(encoding="utf-8").splitlines()
+    lines = page.read_text().splitlines()
     out: list[str] = []
     problems: list[str] = []
     i = 0
@@ -174,7 +174,7 @@ def process(page: Path, write: bool, shown: set[str]) -> list[str]:
         out.append(CLOSE)
         i = close + 1
     if write:
-        page.write_text("\n".join(out) + "\n", encoding="utf-8")
+        page.write_text("\n".join(out) + "\n")
     return problems
 
 
diff --git a/tests/sink.py b/tests/sink.py
index 2443ef0..fe2cd6c 100755
--- a/tests/sink.py
+++ b/tests/sink.py
@@ -16,7 +16,7 @@ def do_POST(self) -> None:
         try:
             item = json.loads(body)
         except ValueError:
-            item = body.decode("utf-8", "replace")
+            item = body.decode(errors="replace")
         with lock:
             received.append(item)
         self.send_response(204)