# TASK 55 — Disk hygiene: log rotation + low-disk guard (queued 2026-10-09)

> Catalog: [`TASKS.md`](../TASKS.md) — status and requirements live here.

**Why (creator ask, 2026-10-09):** "we need some sort of log-rotation so that we don't
inadvertently fill up a user's drive." A free app that quietly eats disk space is a support
ticket and a trust breach.

**What's known (from the 2026-10-09 privacy-policy code research — re-verify before building):**
- `Helpers/AppLog.cs` appends to `%APPDATA%\ytLlive\startup.log`, a timestamped line per entry,
  with **no size cap or rotation found** (not specifically searched — confirm first).
- `Services/Encoder/FfmpegEncoder.cs` (~:371) logs **every non-progress ffmpeg stderr line**
  (≤400 chars each) — the main growth source over long streams.
- Default alert clip is written to `%TEMP%\ytLive-alert-<id>.mp4`
  (`ViewModels/MainViewModel.Chat.cs` ~:106) — confirm whether it's ever deleted.
- Recordings (`.mp4`, default `Downloads`) are user-directed, but nothing checks free space.

**Slices (one integration test each, in order):**

1. ☐ **Size-capped log rotation** — when `startup.log` passes a cap (~5 MB), roll it to
   `startup.1.log` (keep 1–2 old files), start fresh. Test: write past the cap, assert the roll
   and the bounded total. Standard pattern (NLog/Serilog `fileSizeLimitBytes` +
   `retainedFileCountLimit`) — cite in the commit.
2. ☐ **Temp alert clip cleanup** — delete the `%TEMP%` alert clip on app close (and sweep
   stale ones at startup). Test: create, close, assert gone.
3. ☐ **Low-disk guard for recordings** — check free space on the record folder's drive before
   Record starts, and warn (toast) when it runs low mid-recording. Thresholds TBD with the creator.

**Design decisions:** keep `AppLog`'s call surface unchanged — rotation lives inside it.