diff --git a/tests/test_cli.py b/tests/test_cli.py
index f4bec77..6e08493 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -333,6 +333,41 @@ def fake_run_client_action(ctx, action):
         assert called["kwargs"]["xsec_token"] == "token-abc"
         assert called["kwargs"]["xsec_source"] == "pc_search"
 
+    def test_sub_comments_passes_xsec_token(self, monkeypatch):
+        called = {}
+
+        class FakeClient:
+            def get_sub_comments(self, note_id, comment_id, cursor="", xsec_token=""):
+                called["note_id"] = note_id
+                called["comment_id"] = comment_id
+                called["cursor"] = cursor
+                called["xsec_token"] = xsec_token
+                return {"comments": []}
+
+        def fake_handle_command(ctx, action, render, as_json, as_yaml):
+            action(FakeClient())
+            return None
+
+        monkeypatch.setattr("xhs_cli.commands.reading.handle_command", fake_handle_command)
+
+        result = runner.invoke(cli, [
+            "sub-comments",
+            "note-123",
+            "comment-456",
+            "--cursor",
+            "cursor-789",
+            "--xsec-token",
+            "synthetic-token",
+        ])
+
+        assert result.exit_code == 0
+        assert called == {
+            "note_id": "note-123",
+            "comment_id": "comment-456",
+            "cursor": "cursor-789",
+            "xsec_token": "synthetic-token",
+        }
+
     def test_read_index_not_found_returns_usage_error(self, monkeypatch):
         monkeypatch.setattr("xhs_cli.note_refs.get_note_by_index", lambda idx: None)
 
diff --git a/tests/test_client.py b/tests/test_client.py
index eb55af7..a123671 100644
--- a/tests/test_client.py
+++ b/tests/test_client.py
@@ -102,6 +102,41 @@ def close(self):
 
 
 class TestReadingEndpointBehavior:
+    def test_get_sub_comments_sends_browser_query_parameters(self, monkeypatch):
+        captured = {}
+
+        def fake_get(self, uri, params=None):
+            captured["uri"] = uri
+            captured["params"] = params
+            return {"comments": []}
+
+        monkeypatch.setattr(XhsClient, "_main_api_get", fake_get)
+
+        client = XhsClient({"a1": "cookie"})
+        try:
+            result = client.get_sub_comments(
+                "note-123",
+                "comment-456",
+                cursor="cursor-789",
+                xsec_token="synthetic-token",
+            )
+        finally:
+            client.close()
+
+        assert result == {"comments": []}
+        assert captured == {
+            "uri": "/api/sns/web/v2/comment/sub/page",
+            "params": {
+                "note_id": "note-123",
+                "root_comment_id": "comment-456",
+                "num": 30,
+                "cursor": "cursor-789",
+                "image_formats": "jpg,webp,avif",
+                "top_comment_id": "",
+                "xsec_token": "synthetic-token",
+            },
+        }
+
     def test_get_note_detail_prefers_cached_xsec_source(self, monkeypatch):
         captured = {}
 
diff --git a/xhs_cli/client_mixins.py b/xhs_cli/client_mixins.py
index b4dada7..a1be28a 100644
--- a/xhs_cli/client_mixins.py
+++ b/xhs_cli/client_mixins.py
@@ -472,12 +472,16 @@ def get_sub_comments(
         root_comment_id: str,
         num: int = 30,
         cursor: str = "",
+        xsec_token: str = "",
     ) -> Any:
         return self._main_api_get("/api/sns/web/v2/comment/sub/page", {
             "note_id": note_id,
             "root_comment_id": root_comment_id,
             "num": num,
             "cursor": cursor,
+            "image_formats": "jpg,webp,avif",
+            "top_comment_id": "",
+            "xsec_token": xsec_token,
         })
 
 
diff --git a/xhs_cli/commands/reading.py b/xhs_cli/commands/reading.py
index 33f5980..2aef61c 100644
--- a/xhs_cli/commands/reading.py
+++ b/xhs_cli/commands/reading.py
@@ -229,13 +229,27 @@ def topics(ctx, keyword: str, as_json: bool, as_yaml: bool):
 @click.argument("note_id")
 @click.argument("comment_id")
 @click.option("--cursor", default="", help="Pagination cursor")
+@click.option("--xsec-token", default="", help="Security token")
 @structured_output_options
 @click.pass_context
-def sub_comments(ctx, note_id: str, comment_id: str, cursor: str, as_json: bool, as_yaml: bool):
+def sub_comments(
+    ctx,
+    note_id: str,
+    comment_id: str,
+    cursor: str,
+    xsec_token: str,
+    as_json: bool,
+    as_yaml: bool,
+):
     """View replies to a specific comment."""
     handle_command(
         ctx,
-        action=lambda client: client.get_sub_comments(note_id, comment_id, cursor=cursor),
+        action=lambda client: client.get_sub_comments(
+            note_id,
+            comment_id,
+            cursor=cursor,
+            xsec_token=xsec_token,
+        ),
         render=render_comments,
         as_json=as_json,
         as_yaml=as_yaml,