diff --git a/hosts/hass.windy.lan.md b/hosts/hass.windy.lan.md
index f6d7f29..2528cbd 100644
--- a/hosts/hass.windy.lan.md
+++ b/hosts/hass.windy.lan.md
@@ -279,6 +279,15 @@ updated 2026-08-29 (W1N-240 + W1N-242):** 「本月累计」gauge 对齐夏季
 数据日）。备份 `csg_sensors.yaml.bak-20260829-w1n242`。验证：Core
 restart 后回归值不变（334.81 / -0.3 / 10.8 / 90.3 / 200.94 / 180.28）。
 
+**CSG 长期归档（W1N-243, 2026-08-29）:** scribe 库新增 `csg_history`
+表（逐日 usage/cost/ladder/balance + 逐月累计；2026-07-01 起回填，永久），
+由 TimescaleDB 每日任务 **1008** `csg_daily_snapshot()`（22:30
+Asia/Shanghai；**TS job 非 pg_cron**）upsert 维护。日费用在原生
+`latest_day_cost` 缺失时回退 = 昨日用电 × 当前档费率（模板
+`csg_current_ladder_tariff` 0.639）；月费用回退模板
+`csg_this_month_ladder_cost`。**语义**：day 行 usage/cost 为该日值，
+ladder/balance 为 22:30 快照值。详见 [hosts/pgdb.md](../hosts/pgdb.md)。
+
 > **Seasonal gauge switch (W1N-240 已知事项):** 每年 **11-01** 把
 > `power-monitor` 视图「本月累计」gauge 切到冬季 `max:450` /
 > `0/200/400`，**5-01** 切回夏季 `max:650` / `0/260/600`（与模板
@@ -407,8 +416,12 @@ deployed 2026-08-18 from `216cc99` (backup
   a major rewrite (writer.py largely rewritten, migration.py removed, TimescaleDB
   extension required): re-read release notes before upgrading. Do not expect
   retention YAML keys to validate on 3.8.0.
-- Recorder stays external-Postgres with `purge_keep_days: 30` for daily UI
-  history; Scribe is the permanent archive.
+- Recorder stays external-Postgres with `purge_keep_days: 365` (W1N-243,
+  2026-08-29, raised from 30 — ~300 MB/yr, 1% of the 30G pgdb disk) for
+  native UI per-change history; Scribe is the permanent archive. Long-term
+  statistics stay permanent (not purged by `purge_keep_days`). Note:
+  extending retention does **not** recover pre-2026-08-29 raw history
+  (already purged); only `csg_history` day/month values cover that period.
 
 ### Config layout: scribe.yaml + templates/ merge (W1N-238, verified 2026-08-29)