fix(memory): preserve genuine pre-delimiter content in merged compaction rows

teknium1 review on #57690: harvesting logic was skipping the ENTIRE merged
row when a compaction summary was appended to the tail message, discarding
real prior user content that context_compressor retains before the
_MERGED_SUMMARY_DELIMITER. Extract and harvest that pre-delimiter segment
instead of dropping it wholesale.

Revert-to-fail: reverting plugins/memory/holographic/__init__.py alone
drops test_merged_into_tail_preserves_genuine_pre_delimiter_preference
(19 passed, 1 failed); restoring the fix returns 20/20 passed.

plugins/memory/holographic/__init__.py

@@ -374,7 +374,32 @@ class HolographicMemoryProvider(MemoryProvider):
     def _auto_extract_facts(self, messages: list) -> None:
         # Local import (pattern used in initialize()): the compressor module is
         # heavier than this plugin and is only needed when auto_extract is on.
-        from agent.context_compressor import is_compaction_summary_message
+        from agent.context_compressor import (
+            _MERGED_PRIOR_CONTEXT_HEADER,
+            _MERGED_SUMMARY_DELIMITER,
+            is_compaction_summary_message,
+        )
+
+        def _pre_delimiter_user_segment(msg: dict):
+            """Return the genuine user text preceding a merged-into-tail
+            compaction summary, or None when the whole message is a summary.
+
+            Merge-into-tail messages (agent/context_compressor.py ~3163-3190)
+            wrap real prior tail content BEFORE ``_MERGED_SUMMARY_DELIMITER``,
+            prefixed with ``_MERGED_PRIOR_CONTEXT_HEADER``, then append the
+            generated handoff summary AFTER the delimiter. Dropping the whole
+            row (as ``is_compaction_summary_message`` alone would suggest)
+            discards that genuine pre-delimiter content too (#57690 review).
+            Only the summary suffix must be excluded from harvesting.
+            """
+            content = msg.get("content", "")
+            if not isinstance(content, str) or _MERGED_SUMMARY_DELIMITER not in content:
+                return None
+            pre = content.split(_MERGED_SUMMARY_DELIMITER, 1)[0]
+            if pre.startswith(_MERGED_PRIOR_CONTEXT_HEADER):
+                pre = pre[len(_MERGED_PRIOR_CONTEXT_HEADER):]
+            pre = pre.strip()
+            return pre or None
 
         _PREF_PATTERNS = [
             re.compile(r'\bI\s+(?:prefer|like|love|use|want|need)\s+(.+)', re.IGNORECASE),
@@ -393,10 +418,17 @@ class HolographicMemoryProvider(MemoryProvider):
             # Compaction handoff summaries can be inserted as role="user"
             # messages; their prose reliably matches the decision patterns, so
             # without this guard the compactor's own output is stored as a
-            # durable "fact" on every rollover (#57682).
-            if is_compaction_summary_message(msg):
+            # durable "fact" on every rollover (#57682). A merge-into-tail
+            # summary also carries genuine pre-delimiter user content in the
+            # SAME row; harvest that segment instead of dropping the whole
+            # message (#57690 review).
+            pre_delimiter_segment = _pre_delimiter_user_segment(msg)
+            if pre_delimiter_segment is not None:
+                content = pre_delimiter_segment
+            elif is_compaction_summary_message(msg):
                 continue
-            content = msg.get("content", "")
+            else:
+                content = msg.get("content", "")
             if not isinstance(content, str) or len(content) < 10:
                 continue
 

tests/plugins/memory/test_holographic_auto_extract.py

@@ -102,9 +102,10 @@ def test_metadata_marked_summary_not_harvested(tmp_path):
     provider.shutdown()
 
 
-def test_merged_into_tail_summary_not_harvested(tmp_path):
+def test_merged_into_tail_summary_suffix_not_harvested_prefix_content_ignored(tmp_path):
     """Merge-into-tail summaries embed the handoff prefix after the delimiter,
-    not at the start of the message."""
+    not at the start of the message. The wrapped pre-delimiter segment here has
+    no fact-pattern match, so nothing is harvested from either side."""
     provider = _make_provider(tmp_path, auto_extract=True)
     merged = _user(
         f"{_MERGED_PRIOR_CONTEXT_HEADER}\nplease fix the login bug\n"
@@ -115,6 +116,27 @@ def test_merged_into_tail_summary_not_harvested(tmp_path):
     provider.shutdown()
 
 
+def test_merged_into_tail_preserves_genuine_pre_delimiter_preference(tmp_path):
+    """#57690 review: teknium1 noted the ENTIRE merged row was being skipped,
+    discarding genuine pre-delimiter user content (context_compressor.py
+    ~3163-3190 retains real prior tail text before the summary). The fix must
+    extract and harvest that segment while still excluding the summary
+    suffix."""
+    provider = _make_provider(tmp_path, auto_extract=True)
+    merged = _user(
+        f"{_MERGED_PRIOR_CONTEXT_HEADER}\n"
+        "I prefer tabs over spaces for indentation\n"
+        f"{_MERGED_SUMMARY_DELIMITER}\n{SUMMARY_MSG}"
+    )
+    provider.on_session_end([merged])
+    facts = _fact_contents(provider)
+    assert len(facts) == 1
+    assert "tabs over spaces" in facts[0]
+    assert "kanban board" not in facts[0]
+    assert "PostgreSQL" not in facts[0]
+    provider.shutdown()
+
+
 def test_real_user_messages_still_extracted_alongside_summary(tmp_path):
     """The guard must skip only the summary, not suppress extraction for the
     genuine user turns around it."""