diff --git a/tests/skill/understand/test_merge_batch_graphs.py b/tests/skill/understand/test_merge_batch_graphs.py
index 7239bfe63..bf0b453c2 100644
--- a/tests/skill/understand/test_merge_batch_graphs.py
+++ b/tests/skill/understand/test_merge_batch_graphs.py
@@ -983,7 +983,7 @@ def _run_merge(self) -> tuple[int, str, dict]:
             capture_output=True, text=True,
         )
         out_path = self.intermediate / "assembled-graph.json"
-        assembled = _j.loads(out_path.read_text()) if out_path.exists() else {}
+        assembled = _j.loads(out_path.read_text(encoding="utf-8")) if out_path.exists() else {}
         return result.returncode, result.stderr, assembled
 
     def test_two_parts_of_one_logical_batch_merge(self) -> None:
@@ -1102,7 +1102,7 @@ def _run_merge(self) -> tuple[int, str, dict]:
             capture_output=True, text=True,
         )
         out_path = self.intermediate / "assembled-graph.json"
-        assembled = _j.loads(out_path.read_text()) if out_path.exists() else {}
+        assembled = _j.loads(out_path.read_text(encoding="utf-8")) if out_path.exists() else {}
         return result.returncode, result.stderr, assembled
 
     def test_fused_filename_emits_stderr_warning(self) -> None:
diff --git a/understand-anything-plugin/skills/understand-domain/extract-domain-context.py b/understand-anything-plugin/skills/understand-domain/extract-domain-context.py
index 061206a65..22568f565 100644
--- a/understand-anything-plugin/skills/understand-domain/extract-domain-context.py
+++ b/understand-anything-plugin/skills/understand-domain/extract-domain-context.py
@@ -123,7 +123,7 @@ def parse_gitignore(project_root: Path) -> list[re.Pattern[str]]:
     if not gitignore.exists():
         return patterns
 
-    for line in gitignore.read_text(errors="replace").splitlines():
+    for line in gitignore.read_text(encoding="utf-8", errors="replace").splitlines():
         line = line.strip()
         if not line or line.startswith("#"):
             continue
@@ -208,7 +208,7 @@ def detect_entry_points(root: Path, file_paths: list[str]) -> list[dict[str, Any
             continue
         full_path = root / rel_path
         try:
-            content = full_path.read_text(errors="replace")
+            content = full_path.read_text(encoding="utf-8", errors="replace")
         except (OSError, UnicodeDecodeError):
             continue
 
@@ -267,7 +267,7 @@ def priority_score(path: str) -> int:
     for rel_path in sorted_paths[:MAX_SAMPLED_FILES]:
         full_path = root / rel_path
         try:
-            content = full_path.read_text(errors="replace")
+            content = full_path.read_text(encoding="utf-8", errors="replace")
         except (OSError, UnicodeDecodeError):
             continue
 
@@ -312,7 +312,7 @@ def extract_metadata(root: Path) -> dict[str, Any]:
         if not filepath.exists():
             continue
         try:
-            content = filepath.read_text(errors="replace")
+            content = filepath.read_text(encoding="utf-8", errors="replace")
         except (OSError, UnicodeDecodeError):
             continue
 
@@ -415,7 +415,7 @@ def main() -> None:
 
         context = _truncate_to_fit(context)
         output = json.dumps(context, indent=2)
-        output_path.write_text(output)
+        output_path.write_text(output, encoding="utf-8")
         size_kb = len(output.encode()) / 1024
         print(f"  Wrote {output_path} ({size_kb:.0f} KB)", file=sys.stderr)