diff --git a/scripts/refresh.py b/scripts/refresh.py
index 252c278..f329cb1 100644
--- a/scripts/refresh.py
+++ b/scripts/refresh.py
@@ -116,10 +116,10 @@ def main(argv: list[str] | None = None) -> int:
     common.preflight_checks(["git", "buildx"])
 
     cli = args.stellar_cli_version
-    data = builds.load()
-    entry = builds.find_cli(data, cli)
 
     try:
+        data = builds.load()
+        entry = builds.find_cli(data, cli)
         if args.rust_versions:
             labels = [k.strip() for k in args.rust_versions.split(",") if k.strip()]
             common.log(f"rust base labels (from --rust-versions): {' '.join(labels)}")
diff --git a/scripts/validate_json.py b/scripts/validate_json.py
index c5338e4..8e12a35 100755
--- a/scripts/validate_json.py
+++ b/scripts/validate_json.py
@@ -90,8 +90,12 @@ def main(argv: list[str] | None = None) -> int:
 
     builds_path = root / "builds.json"
     schema_path = root / "builds.schema.json"
-    builds_data = json.loads(builds_path.read_text())
-    schema = json.loads(schema_path.read_text())
+    try:
+        builds_data = json.loads(builds_path.read_text())
+        schema = json.loads(schema_path.read_text())
+    except (OSError, UnicodeDecodeError, json.JSONDecodeError) as exc:
+        common.err(f"could not load builds.json/builds.schema.json: {exc}")
+        return 1
 
     ok &= check_schema(builds_data, schema)
 
diff --git a/tests/integration/test_refresh.py b/tests/integration/test_refresh.py
index 3abe4ab..c3dd7af 100644
--- a/tests/integration/test_refresh.py
+++ b/tests/integration/test_refresh.py
@@ -156,6 +156,17 @@ def test_creates_new_cli_entry(monkeypatch: pytest.MonkeyPatch, staged_minimal:
     assert [e["version"] for e in data["stellar_cli_versions"]] == ["26.0.0", "27.0.0"]
 
 
+def test_malformed_builds_dies_cleanly(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
+    # A malformed builds.json must route through common.die() (SystemExit),
+    # not surface a raw JSONDecodeError from builds.load().
+    target = tmp_path / "builds.json"
+    target.write_text("{ this is not valid json")
+    monkeypatch.setattr(builds, "DEFAULT_PATH", target)
+    monkeypatch.setattr(refresh.common, "preflight_checks", lambda _: None)
+    with pytest.raises(SystemExit):
+        refresh.main(["--stellar-cli-version", "26.0.0", "--rust-versions", "1.94.0-slim-trixie"])
+
+
 def test_unresolvable_tag_dies(monkeypatch: pytest.MonkeyPatch, staged_minimal: Path) -> None:
     monkeypatch.setattr(refresh.common, "preflight_checks", lambda _: None)
     monkeypatch.setattr(refresh.git_remote, "resolve_tag_commit", lambda repo, tag: None)
diff --git a/tests/unit/test_validate_json.py b/tests/unit/test_validate_json.py
index d6e6dbc..a19e47f 100644
--- a/tests/unit/test_validate_json.py
+++ b/tests/unit/test_validate_json.py
@@ -91,3 +91,26 @@ def test_main_fails_on_invalid_entry(
     )
     monkeypatch.setattr(validate_json.common, "repo_root", lambda: tmp_path)
     assert validate_json.main([]) == 1
+
+
+def test_main_returns_1_on_malformed_builds(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch, fixtures_dir: Path
+) -> None:
+    # A malformed builds.json must exit 1 cleanly, not raise JSONDecodeError.
+    (tmp_path / "builds.json").write_text("{ this is not valid json")
+    (tmp_path / "builds.schema.json").write_text(
+        (fixtures_dir.parent.parent / "builds.schema.json").read_text()
+    )
+    monkeypatch.setattr(validate_json.common, "repo_root", lambda: tmp_path)
+    assert validate_json.main([]) == 1
+
+
+def test_main_returns_1_on_missing_builds(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch, fixtures_dir: Path
+) -> None:
+    # A missing builds.json must exit 1 cleanly, not raise FileNotFoundError.
+    (tmp_path / "builds.schema.json").write_text(
+        (fixtures_dir.parent.parent / "builds.schema.json").read_text()
+    )
+    monkeypatch.setattr(validate_json.common, "repo_root", lambda: tmp_path)
+    assert validate_json.main([]) == 1