diff --git a/lib/substantive_fixer.py b/lib/substantive_fixer.py
index 907f6f2..e5878db 100644
--- a/lib/substantive_fixer.py
+++ b/lib/substantive_fixer.py
@@ -650,22 +650,25 @@ async def verdict_deadlock_reaper_cycle(conn) -> int:
     #
     # Branch allowlist invariant: the reaper closes ONLY disposable, pipeline-
     # generated branches — content the pipeline (or a daily cron) created and
-    # can recreate. Three classes qualify:
+    # can recreate. Four classes qualify:
     #
     #   extract/* — per-source extraction PRs, regenerated next ingest cycle
     #   reweave/* — nightly graph-edge maintenance, regenerated next reweave
     #   fix/*     — pipeline-internal fix branches
-    #   */research-2* — daily {agent}/research-{YYYY-MM-DD} sessions; the date
-    #                   suffix scopes this to cron-generated outputs only and
-    #                   excludes hand-named research branches like
-    #                   rio/research-batch-agents-memory-harnesses, which are
-    #                   feature work owned by the agent.
+    #   */research-YYYY-MM-DD — daily {agent}/research-{date} cron sessions.
+    #                   Matched via SQLite `_` single-char wildcards as
+    #                   `research-20__-__-__` to literally enforce the date-
+    #                   suffix shape. Excludes hand-named research branches
+    #                   (rio/research-batch-agents-memory-harnesses,
+    #                   theseus/research-2nd-attempt-on-X, etc.) which are
+    #                   feature work owned by the agent. Pattern good through
+    #                   2099; revisit then.
     #
     # WIP agent feature branches (theseus/feature-foo, epimetheus/some-fix,
     # rio/research-thesis-name) are NEVER reaped — owners review their own PRs
-    # on their own cadence. The */research-2* pattern threads the needle: it
-    # picks up daily synthesis output that the agent will regenerate tomorrow
-    # while leaving manually-named research work alone.
+    # on their own cadence. The date-shaped pattern threads the needle: picks
+    # up daily synthesis output the agent regenerates tomorrow while leaving
+    # manually-named research work alone.
     rows = conn.execute(
         """SELECT number, branch, eval_issues, leo_verdict, domain_verdict,
                   last_attempt, fix_attempts
@@ -677,7 +680,7 @@ async def verdict_deadlock_reaper_cycle(conn) -> int:
            AND (branch LIKE 'extract/%'
                 OR branch LIKE 'reweave/%'
                 OR branch LIKE 'fix/%'
-                OR branch LIKE '%/research-2%')
+                OR branch LIKE '%/research-20__-__-__')
            AND (
                (leo_verdict = 'request_changes' AND domain_verdict = 'approve')
                OR (leo_verdict = 'skipped' AND domain_verdict = 'request_changes')