diff --git a/proxmox-monitor.prose.md b/proxmox-monitor.prose.md
index a7904e1..5fbc6f8 100644
--- a/proxmox-monitor.prose.md
+++ b/proxmox-monitor.prose.md
@@ -89,6 +89,30 @@ agent: abiba
 | minipve | 192.168.68.12 | PVE |
 | amdpve | 192.168.68.15 | PVE + Strix Halo LLM (strix-moe) |
 
+## PBS GC (Proxmox Backup Server)
+
+### Schedule
+Cron `0 20 * * *` on the **storepve HOST** (192.168.68.6) = 20:00 America/New_York local = **00:00 UTC**.
+
+**NOTE**: The closed PR #116 said "20:00 UTC" — this is WRONG by four hours. Do not copy it.
+
+### What Actually Runs
+Host script `/usr/local/bin/pbs-gc.sh` runs `pct exec 107 -- proxmox-backup-manager garbage-collection start storepve-datastore`.
+
+**IMPORTANT**: The tool `proxmox-backup-manager` exists only inside CT 107 (where the PBS server runs). The storepve host has only `proxmox-backup-client`. This is why the job had never worked before 2026-09-19 00:00 UTC.
+
+### Datastore Location
+- **Datastore**: CT 107's `/mnt/pbs-backup` on the storepve ZFS dataset `/tank/pbs-backup` (pool `tank`, ~11T free)
+- **NOT** `/media/easystore2` (media library, 3.7T, 96% used — separate volume)
+
+### Liveness Check
+The new `proxmox-monitor.sh` leg checks storepve-datastore GC health:
+- Reads GC state from CT 107: `pct exec 107 -- proxmox-backup-manager garbage-collection list --output-format json`
+- **FAILS** if `last-run-endtime` is older than 48 hours
+- Reports age in hours and pending-bytes
+- A failed probe (000/timeout) is reported as `probe-failed: storepve:192.168.68.6 (expected JSON, got 000)` — **never** rendered as "GC stale"
+- The healthy branch prints an explicit healthy line: `✅ PBS GC: healthy (last run Xh ago)`
+
 ## Operations
 
 ### view-dashboards