fix(tools): show compression-continuation sessions in session search results (#13840)

tests/tools/test_session_search_compression.py

@@ -0,0 +1,51 @@
+"""Tests for session_search compression-continuation visibility (#13840).
+
+Compression-ended sessions have parent_session_id set (they are continuation
+children of compressed parents).  The blanket parent_session_id filter
+excluded them from search results, making compressed sessions invisible.
+"""
+import json
+import pytest
+from unittest.mock import MagicMock, patch
+
+
+class TestListRecentSessionsCompression:
+    """Compression-continuation sessions must be visible in recent sessions (#13840)."""
+
+    def _run_list_recent(self, sessions, current_session_id=None):
+        from tools.session_search_tool import _list_recent_sessions
+        db = MagicMock()
+        db.list_sessions_rich.return_value = sessions
+        db.get_session.return_value = None
+        return json.loads(_list_recent_sessions(db, limit=10, current_session_id=current_session_id))
+
+    def test_compression_continuation_visible(self):
+        """Sessions with parent_session_id AND end_reason=compression must be visible."""
+        sessions = [
+            {"id": "session-2", "parent_session_id": "session-1", "end_reason": "compression",
+             "title": "Continued after compression", "source": "cli", "started_at": "", "last_active": "",
+             "message_count": 5, "preview": "hello"},
+        ]
+        result = self._run_list_recent(sessions)
+        assert result["success"]
+        assert len(result["results"]) == 1
+        assert result["results"][0]["session_id"] == "session-2"
+
+    def test_delegation_child_still_hidden(self):
+        """Sessions with parent_session_id but no compression end_reason stay hidden."""
+        sessions = [
+            {"id": "delegate-1", "parent_session_id": "parent-1", "end_reason": None,
+             "title": "Delegated task", "source": "cli", "started_at": "", "last_active": "",
+             "message_count": 3, "preview": "sub-task"},
+        ]
+        result = self._run_list_recent(sessions)
+        assert len(result["results"]) == 0
+
+    def test_root_sessions_still_visible(self):
+        """Sessions without parent_session_id are always visible."""
+        sessions = [
+            {"id": "root-1", "parent_session_id": None, "title": "Root session",
+             "source": "cli", "started_at": "", "last_active": "", "message_count": 10, "preview": "hi"},
+        ]
+        result = self._run_list_recent(sessions)
+        assert len(result["results"]) == 1

tools/session_search_tool.py

@@ -123,8 +123,10 @@ def _list_recent_sessions(db, limit: int, current_session_id: str = None) -> str
             sid = s.get("id", "")
             if current_root and (sid == current_root or sid == current_session_id):
                 continue
-            # Skip child / delegation sessions
-            if s.get("parent_session_id"):
+            # Skip child/delegation sessions, but keep compression-continuation
+            # sessions — their parent ended via compression, not delegation,
+            # and they carry the active conversation forward (#13840).
+            if s.get("parent_session_id") and s.get("end_reason") != "compression":
                 continue
             results.append({
                 "session_id": sid,