diff --git a/src/docs/deployment.md b/src/docs/deployment.md
index 86ea92f..82f3b8d 100644
--- a/src/docs/deployment.md
+++ b/src/docs/deployment.md
@@ -124,6 +124,7 @@ xce_controller \
   ```
   TLS verification is `SSL_VERIFY_NONE` everywhere in this codebase — no hostname/identity check is enforced regardless of CA, so a CA-signed cert buys you encryption, not authentication.
 - Exactly one node (conventionally the first started) needs its `conf/` seeded with an initial `cluster.bin` (via `xceadmin config build`) before first boot; other nodes receive config over the wire via config-push once joined.
+- **WAL and snapshot retention in `data/` is fully automatic — no manual purging needed.** Every checkpoint trims WAL segments below a replication-safe floor (a segment is never deleted while any standby still needs it to catch up) and rotates old snapshots down to `snap_keep_n` most recent (default 2 — current + one previous, kept as a last-known-good fallback if a checkpoint is later found corrupt). `snap_keep_n` is tunable via the cluster config's `PersistConfig.snapKeepN` field, not a CLI flag.
 
 ### Local dev cluster (fully automated)