diff --git a/plans/0012-the-archivist.md b/plans/0012-the-archivist.md
index 9f14a63..c9856f2 100644
--- a/plans/0012-the-archivist.md
+++ b/plans/0012-the-archivist.md
@@ -166,6 +166,16 @@ Backfill stays cheap the same way. It is triggered by a new entity or a
 new alias, and it visits the places a search for those names turns up.
 It is not a standing re-read of all history.
 
+One writer at a time. A play session and an Archivist pass each hold
+the world lock, a lock file at the world root, for as long as they
+run. Note writes are atomic regardless, a temp file renamed into
+place, so injection can never read a half-written note. But renames,
+merges, and record annotation change what other files point at, and
+those happen only under the lock. Chris's hand edits stay
+uncoordinated; the Archivist's conservative charter is what makes them
+safe. This is also why live trailing waits: an Archivist inside a live
+session needs finer locks than one world lock.
+
 ## The guard on the record
 
 Backfilling means the Archivist touches the record, and that needs a
@@ -305,8 +315,11 @@ before the agent that uses it, and the Archivist earns record access
 last.
 
 1. **The note format.** Seeded stubs, frontmatter, alias-aware
-   resolution; the `## Mentions` stamp folds into the seed line. *You
-   can now: open a stub and read the scene that created it.*
+   resolution; the `## Mentions` stamp folds into the seed line. The
+   session loads every note's address and aliases into the resolver at
+   startup, so a bare name cannot re-establish an entity that already
+   exists on disk. *You can now: open a stub and read the scene that
+   created it.*
 2. **Injection.** 0011 step 3 on the new format: referenced notes
    reach the next turn's prompt. *You can now: watch the DM keep an
    entity's facts straight two turns after naming it.*