fix(telegram): escape send_slash_confirm preview with format_message

send_slash_confirm() sent the raw command preview with ParseMode.MARKDOWN,
skipping the format_message() conversion applied to every other dynamic
send in the adapter. Commands with underscores, dots, brackets, or other
MarkdownV2-sensitive characters raised BadRequest: Can't parse entities;
the exception was swallowed by the outer try/except, so the confirmation
prompt silently never appeared.

Fix: wrap preview through format_message() and switch to MARKDOWN_V2,
symmetric with send_update_prompt and the callback sends fixed in
a69404052.

gateway/platforms/telegram.py

@@ -2297,9 +2297,7 @@ class TelegramAdapter(BasePlatformAdapter):
             return SendResult(success=False, error="Not connected")
 
         try:
-            # Message body: render as plain text (message already contains
-            # markdown formatting from the gateway primitive).
-            preview = message if len(message) <= 3800 else message[:3800] + "..."
+            preview = self.format_message(message if len(message) <= 3800 else message[:3800] + "...")
 
             keyboard = InlineKeyboardMarkup([
                 [
@@ -2315,7 +2313,7 @@ class TelegramAdapter(BasePlatformAdapter):
             kwargs: Dict[str, Any] = {
                 "chat_id": int(chat_id),
                 "text": preview,
-                "parse_mode": ParseMode.MARKDOWN,
+                "parse_mode": ParseMode.MARKDOWN_V2,
                 "reply_markup": keyboard,
                 **self._link_preview_kwargs(),
             }

tests/gateway/test_telegram_slash_confirm.py

@@ -0,0 +1,109 @@
+"""Regression guard: send_slash_confirm must use format_message + MARKDOWN_V2."""
+
+import sys
+from pathlib import Path
+from types import SimpleNamespace
+from unittest.mock import AsyncMock, MagicMock
+
+import pytest
+
+_repo = str(Path(__file__).resolve().parents[2])
+if _repo not in sys.path:
+    sys.path.insert(0, _repo)
+
+
+def _ensure_telegram_mock():
+    if "telegram" in sys.modules and hasattr(sys.modules["telegram"], "__file__"):
+        return
+    mod = MagicMock()
+    mod.ext.ContextTypes.DEFAULT_TYPE = type(None)
+    mod.constants.ParseMode.MARKDOWN = "Markdown"
+    mod.constants.ParseMode.MARKDOWN_V2 = "MarkdownV2"
+    mod.constants.ParseMode.HTML = "HTML"
+    mod.constants.ChatType.PRIVATE = "private"
+    mod.constants.ChatType.GROUP = "group"
+    mod.constants.ChatType.SUPERGROUP = "supergroup"
+    mod.constants.ChatType.CHANNEL = "channel"
+    mod.error.NetworkError = type("NetworkError", (OSError,), {})
+    mod.error.TimedOut = type("TimedOut", (OSError,), {})
+    mod.error.BadRequest = type("BadRequest", (Exception,), {})
+    for name in ("telegram", "telegram.ext", "telegram.constants", "telegram.request"):
+        sys.modules.setdefault(name, mod)
+    sys.modules.setdefault("telegram.error", mod.error)
+
+
+_ensure_telegram_mock()
+
+from gateway.platforms.telegram import TelegramAdapter
+from gateway.config import PlatformConfig
+
+
+def _make_adapter():
+    config = PlatformConfig(enabled=True, token="test-token", extra={})
+    adapter = TelegramAdapter(config)
+    adapter._bot = AsyncMock()
+    adapter._app = MagicMock()
+    return adapter
+
+
+class TestSendSlashConfirm:
+
+    @pytest.mark.asyncio
+    async def test_uses_markdown_v2_and_escapes_special_chars(self):
+        """send_slash_confirm must pass preview through format_message and use
+        MARKDOWN_V2 — so commands with underscores, dots, or brackets don't
+        raise BadRequest: Can't parse entities."""
+        adapter = _make_adapter()
+        sent = {}
+
+        async def mock_send(**kwargs):
+            sent.update(kwargs)
+            return SimpleNamespace(message_id=7)
+
+        adapter._bot.send_message = AsyncMock(side_effect=mock_send)
+
+        result = await adapter.send_slash_confirm(
+            chat_id="100",
+            title="Confirm",
+            message="/run script_name.sh --flag=value [option]",
+            session_key="sk",
+            confirm_id="cid1",
+        )
+
+        assert result.success is True
+        assert "MARKDOWN_V2" in repr(sent["parse_mode"])
+        # Underscores and dots must be escaped by format_message
+        assert "script\\_name" in sent["text"]
+        assert "\\." in sent["text"]
+
+    @pytest.mark.asyncio
+    async def test_stores_slash_confirm_state(self):
+        adapter = _make_adapter()
+        adapter._bot.send_message = AsyncMock(
+            return_value=SimpleNamespace(message_id=8)
+        )
+
+        await adapter.send_slash_confirm(
+            chat_id="100",
+            title="Confirm",
+            message="reload-mcp",
+            session_key="my-session",
+            confirm_id="cid2",
+        )
+
+        assert adapter._slash_confirm_state["cid2"] == "my-session"
+
+    @pytest.mark.asyncio
+    async def test_not_connected_returns_failure(self):
+        adapter = _make_adapter()
+        adapter._bot = None
+
+        result = await adapter.send_slash_confirm(
+            chat_id="100",
+            title="Confirm",
+            message="reload-mcp",
+            session_key="sk",
+            confirm_id="cid3",
+        )
+
+        assert result.success is False