fix: sanitize Telegram help command mentions

tests/gateway/test_gateway_command_help.py

@@ -0,0 +1,78 @@
+"""Gateway command help rendering tests."""
+
+import pytest
+
+from gateway.config import Platform
+from gateway.platforms.base import MessageEvent
+from gateway.session import SessionSource
+
+
+def _make_event(text: str, platform: Platform) -> MessageEvent:
+    return MessageEvent(
+        text=text,
+        source=SessionSource(
+            platform=platform,
+            chat_id="chat-1",
+            user_id="user-1",
+            user_name="tester",
+            chat_type="dm",
+        ),
+    )
+
+
+def _make_runner():
+    from gateway.run import GatewayRunner
+
+    return object.__new__(GatewayRunner)
+
+
+@pytest.mark.asyncio
+async def test_help_sanitizes_slash_command_mentions_for_telegram(monkeypatch):
+    """Telegram help output must not expose invalid uppercase/hyphenated slashes."""
+    monkeypatch.setattr(
+        "agent.skill_commands.get_skill_commands",
+        lambda: {
+            "/Linear": {"description": "Open Linear"},
+            "/Custom-Thing": {"description": "Run a custom thing"},
+        },
+    )
+
+    result = await _make_runner()._handle_help_command(
+        _make_event("/help", Platform.TELEGRAM)
+    )
+
+    assert "`/linear`" in result
+    assert "`/custom_thing`" in result
+    assert "`/Linear`" not in result
+    assert "`/Custom-Thing`" not in result
+
+
+@pytest.mark.asyncio
+async def test_commands_sanitizes_slash_command_mentions_for_telegram(monkeypatch):
+    """Paginated Telegram /commands output uses Telegram-valid slash mentions."""
+    monkeypatch.setattr(
+        "agent.skill_commands.get_skill_commands",
+        lambda: {"/Linear": {"description": "Open Linear"}},
+    )
+
+    result = await _make_runner()._handle_commands_command(
+        _make_event("/commands 999", Platform.TELEGRAM)
+    )
+
+    assert "`/linear`" in result
+    assert "`/Linear`" not in result
+
+
+@pytest.mark.asyncio
+async def test_help_keeps_non_telegram_slash_command_mentions_unchanged(monkeypatch):
+    """Only Telegram needs slash mentions rewritten to Telegram command names."""
+    monkeypatch.setattr(
+        "agent.skill_commands.get_skill_commands",
+        lambda: {"/Linear": {"description": "Open Linear"}},
+    )
+
+    result = await _make_runner()._handle_help_command(
+        _make_event("/help", Platform.DISCORD)
+    )
+
+    assert "`/Linear`" in result