diff --git a/agent/prompt_builder.py b/agent/prompt_builder.py
index d907a581583..456cd099ea1 100644
--- a/agent/prompt_builder.py
+++ b/agent/prompt_builder.py
@@ -157,6 +157,9 @@ MEMORY_GUIDANCE = (
     "User preferences and recurring corrections matter more than procedural task details.\n"
     "Do NOT save task progress, session outcomes, completed-work logs, or temporary TODO "
     "state to memory; use session_search to recall those from past transcripts. "
+    "Specifically: do not record PR numbers, issue numbers, commit SHAs, 'fixed bug X', "
+    "'submitted PR Y', 'Phase N done', file counts, or any artifact that will be stale "
+    "in 7 days. If a fact will be stale in a week, it does not belong in memory. "
     "If you've discovered a new way to do something, solved a problem that could be "
     "necessary later, save it as a skill with the skill tool.\n"
     "Write memories as declarative facts, not instructions to yourself. "