diff --git a/scripts/profile_sync.py b/scripts/profile_sync.py
index 580f677b..d2796098 100644
--- a/scripts/profile_sync.py
+++ b/scripts/profile_sync.py
@@ -3027,6 +3027,31 @@ def main() -> None:
                 file=sys.stderr,
             )
             raise SystemExit(1)
+    machine = [
+        flag for flag, on in (
+            ("--json", args.as_json),
+            ("--markdown", args.markdown),
+            ("--fetch-plan", args.fetch_plan),
+            ("--triage", args.triage),
+        ) if on
+    ]
+    extras = [
+        flag for flag, on in (
+            ("--check-version", args.check_version),
+            ("--detect-new-files", args.detect_new_files),
+            ("--watch-hashes", args.watch_hashes),
+            ("--full-diff", args.full_diff),
+            ("--tree-diff", args.tree_diff),
+        ) if on
+    ]
+    if machine and extras:
+        # The extra sections only exist in the text report; the other outputs
+        # returned before reaching them and printed as if never asked.
+        print(
+            f"{', '.join(machine)} does not carry {', '.join(extras)}",
+            file=sys.stderr,
+        )
+        raise SystemExit(1)
     profiles = load_emulator_profiles(args.emulators_dir, skip_aliases=False)
     selected = select_profiles(profiles, args)
     _check_quota(len(selected), args.offline)
@@ -3094,22 +3119,28 @@ def main() -> None:
                 # The guard already left the file untouched; keep going.
                 print(f"{name}: write refused: {exc}", file=sys.stderr)
 
+    # --changed-only narrows every output, not the text report alone: the
+    # documented `--all --changed-only --json` listed every profile.
+    shown = [
+        report for report in reports
+        if not args.changed_only or report.needs_review()
+    ]
     if args.as_json:
-        print(json.dumps([report_to_dict(r) for r in reports], indent=2))
+        print(json.dumps([report_to_dict(r) for r in shown], indent=2))
         return
     if args.markdown:
         target = Path(args.report_dir) / f"profile-sync-{date.today().isoformat()}.md"
         target.parent.mkdir(parents=True, exist_ok=True)
-        target.write_text(format_markdown(reports), encoding="utf-8")
+        target.write_text(format_markdown(shown), encoding="utf-8")
         print(f"written: {target}")
         return
     if args.fetch_plan:
-        for report in reports:
+        for report in shown:
             for url in fetch_plan(report):
                 print(url)
         return
     if args.triage:
-        _print_triage(args, selected, reports)
+        _print_triage(args, selected, shown)
         return
     printed = 0
     for report in reports:
diff --git a/tests/test_profile_sync.py b/tests/test_profile_sync.py
index 67bb1051..4ffc130e 100644
--- a/tests/test_profile_sync.py
+++ b/tests/test_profile_sync.py
@@ -3293,6 +3293,46 @@ class TestRealignProse(unittest.TestCase):
         self.assertIn("(deep.c:14)", self.path.read_text())
 
 
+class TestOutputModesApplyTheirFlags(unittest.TestCase):
+    """--changed-only narrows --json too; extras are refused off the text report."""
+
+    def _main(self, *argv):
+        from unittest import mock
+
+        clean = ProfileReport(name="clean")
+        drift = ProfileReport(name="drift", counts={"CHANGED": 1})
+        reports = {"clean": clean, "drift": drift}
+        out, err = io.StringIO(), io.StringIO()
+        saved = sys.argv
+        try:
+            sys.argv = ["profile_sync.py", "--all", *argv]
+            with mock.patch.object(profile_sync, "load_emulator_profiles", return_value={}), \
+                    mock.patch.object(profile_sync, "select_profiles",
+                                      return_value={"clean": {}, "drift": {}}), \
+                    mock.patch.object(profile_sync, "_check_quota"), \
+                    mock.patch.object(profile_sync, "build_report",
+                                      side_effect=lambda name, *a, **k: reports[name]), \
+                    contextlib.redirect_stdout(out), contextlib.redirect_stderr(err):
+                try:
+                    profile_sync.main()
+                    code = 0
+                except SystemExit as exc:
+                    code = exc.code
+        finally:
+            sys.argv = saved
+        return code, out.getvalue(), err.getvalue()
+
+    def test_changed_only_narrows_json(self):
+        code, out, _ = self._main("--changed-only", "--json")
+        self.assertEqual(code, 0)
+        self.assertEqual([r["name"] for r in json.loads(out)], ["drift"])
+
+    def test_extras_are_refused_with_json(self):
+        code, _, err = self._main("--json", "--check-version")
+        self.assertEqual(code, 1)
+        self.assertIn("--check-version", err)
+
+
 class TestRealignFlagMatrix(unittest.TestCase):
     """--realign-prose applies a flag or refuses it, never swallows it."""