diff --git a/tests/channels/test_telegram_channel.py b/tests/channels/test_telegram_channel.py
index 4a69d31a..5480b878 100644
--- a/tests/channels/test_telegram_channel.py
+++ b/tests/channels/test_telegram_channel.py
@@ -1591,3 +1591,29 @@ async def test_send_delta_mid_stream_strips_markdown() -> None:
     assert "**" not in edited_text
     assert "Title" in edited_text
     assert "1. step" in edited_text
+
+
+def test_build_keyboard_respects_inline_keyboards_flag() -> None:
+    """``_build_keyboard`` returns ``None`` whenever the feature flag is off,
+    regardless of whether buttons are provided; returns a proper Markup only
+    when the flag is explicitly enabled. Pins the kill-switch so accidentally
+    flipping the default doesn't silently expose callback handlers."""
+    from telegram import InlineKeyboardMarkup
+
+    off = TelegramChannel(
+        TelegramConfig(enabled=True, token="123:abc", inline_keyboards=False),
+        MessageBus(),
+    )
+    assert off._build_keyboard([["A", "B"]]) is None
+
+    on = TelegramChannel(
+        TelegramConfig(enabled=True, token="123:abc", inline_keyboards=True),
+        MessageBus(),
+    )
+    assert on._build_keyboard([]) is None  # empty still no-op
+    markup = on._build_keyboard([["Yes", "No"], ["Cancel"]])
+    assert isinstance(markup, InlineKeyboardMarkup)
+    rows = markup.inline_keyboard
+    assert [[b.text for b in row] for row in rows] == [["Yes", "No"], ["Cancel"]]
+    # callback_data mirrors label so _on_callback_query can echo the tap back.
+    assert rows[0][0].callback_data == "Yes"
diff --git a/tests/tools/test_message_tool.py b/tests/tools/test_message_tool.py
index dc8e11d5..b65b5cd8 100644
--- a/tests/tools/test_message_tool.py
+++ b/tests/tools/test_message_tool.py
@@ -8,3 +8,24 @@ async def test_message_tool_returns_error_when_no_target_context() -> None:
     tool = MessageTool()
     result = await tool.execute(content="test")
     assert result == "Error: No target channel/chat specified"
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize(
+    "bad",
+    [
+        "not a list",
+        [["ok"], "row-not-a-list"],
+        [["ok", 42]],
+        [[None]],
+    ],
+)
+async def test_message_tool_rejects_malformed_buttons(bad) -> None:
+    """``buttons`` must be ``list[list[str]]``; the tool validates the shape
+    up front so a malformed LLM payload errors visibly instead of slipping
+    into the channel layer where Telegram would silently reject the frame."""
+    tool = MessageTool()
+    result = await tool.execute(
+        content="hi", channel="telegram", chat_id="1", buttons=bad,
+    )
+    assert result == "Error: buttons must be a list of list of strings"