diff --git a/DOCUMENT-INDEX.md b/DOCUMENT-INDEX.md
index b021c54..c81c7c7 100644
--- a/DOCUMENT-INDEX.md
+++ b/DOCUMENT-INDEX.md
@@ -27,7 +27,13 @@ root/
 │   ├── sandbox/       ← Brainstorming sessions (Gemini, etc.)
 │   └── archive/       ← Historical session logs and completed plans
 
-### Archived Planning Documents (docs/archive/planning/)
+### Research
+
+| Document | Description |
+|----------|-------------|
+| `docs/archive/research/session-chronicle-feb12-2026.md` | Comprehensive chronicle of Feb 12, 2026 — 'The Day the Essence Patch Worked.' Full session record including personality transfer methodology and lessons learned. |
+
+## Archived Planning Documents (docs/archive/planning/)
 
 | Document | Archived From | Reason |
 |:---------|:-------------|:-------|