diff --git a/configs/wt-gate/wt-gate-scratch.conf b/configs/wt-gate/wt-gate-scratch.conf
new file mode 100644
index 0000000..0de1315
--- /dev/null
+++ b/configs/wt-gate/wt-gate-scratch.conf
@@ -0,0 +1,4 @@
+# lkraven user tmpfiles: the Worldtree memory gate keeps each batch's harness scratch (scripts/wt-memory-gate-batch
+# --keep-data, worldtree-dev 2026-10-17); retention 14 days, cleaned by the user systemd-tmpfiles-clean.timer.
+# Install: cp to ~/.config/user-tmpfiles.d/ and `systemctl --user enable --now systemd-tmpfiles-clean.timer`.
+d %h/.local/state/wt-memory-gate-batch/scratch 0700 - - 14d
diff --git a/scripts/wt-memory-gate-batch b/scripts/wt-memory-gate-batch
index cec62fc..4d27bb5 100755
--- a/scripts/wt-memory-gate-batch
+++ b/scripts/wt-memory-gate-batch
@@ -55,6 +55,7 @@ WT_DEMO_API_CT="${WT_DEMO_API_CT:-worldtree-worldtree-api-1}"
 WT_LEGACY_MODE="${WT_LEGACY_MODE:-off}"
 WT_BATCH_LABEL="${WT_BATCH_LABEL:-window-off}"
 STATE_DIR="${XDG_STATE_HOME:-$HOME/.local/state}/wt-memory-gate-batch"
+SCRATCH_BASE="$STATE_DIR/scratch"   # kept harness scratch, one dir per batch; outside every git checkout
 LOCK_FILE="$STATE_DIR/lock"
 OUT_DIR="$WT_TREE/docs/eval/memory_acceptance_runs"
 
@@ -112,8 +113,14 @@ legacy_args=()
 if git -C "$WT_TREE" grep -q -e '"--legacy-mode"' "$deployed" -- core/memory_acceptance 2>/dev/null; then
   legacy_args=(--legacy-mode "$WT_LEGACY_MODE")
 fi
+# --keep-data (worldtree-dev 2026-10-17, thread 01M555JEFQKK2G3WK155P1X9T1): keep the in-process instance's scratch
+# (its memory writer/reader logs, records store, SQLite) so a miss can be traced after the batch. It only skips the
+# harness's rmtree at stop: the number is the same harness. The scratch lands under $SCRATCH_BASE/<batch id>/ via
+# TMPDIR (the harness mkdtemp's it; there is no --scratch-root flag), OUTSIDE every git checkout, because worldtree-dev
+# commits the run dirs and a SQLite must never ride into the repo. Retention 14 days: lkraven's user tmpfiles rule
+# (configs/wt-gate/wt-gate-scratch.conf -> ~/.config/user-tmpfiles.d/), not an rm in this script.
 cmd=(python -m core.memory_acceptance.live --runs 3 --gate
-     "${legacy_args[@]}" --label "$WT_BATCH_LABEL" --out "$OUT_DIR")
+     "${legacy_args[@]}" --label "$WT_BATCH_LABEL" --out "$OUT_DIR" --keep-data)
 
 echo "wt-memory-gate-batch $(now)"
 echo "  demo image   $image"
@@ -139,8 +146,12 @@ if [[ "$run_tree" == "$WT_GATE_TREE" ]]; then
 fi
 
 # ── 4. run ──────────────────────────────────────────────────────────────────
-log="$STATE_DIR/$(date -u +%Y%m%dT%H%M%SZ).log"   # stderr (progress, errors)
+bid="$(date -u +%Y%m%dT%H%M%SZ)"                    # this batch's id: names the log and the scratch parent
+log="$STATE_DIR/$bid.log"                            # stderr (progress, errors)
 out="${log%.log}.stdout"                             # stdout; its last line is the run dir
+scratch_parent="$SCRATCH_BASE/$bid"
+[[ ! -e "$scratch_parent" ]] || refuse "scratch parent $scratch_parent already exists (the harness needs an empty scratch per batch)"
+mkdir -p -m 0700 "$scratch_parent" || refuse "could not create $scratch_parent"
 echo "  log          $log"
 set +e
 (
@@ -157,6 +168,7 @@ set +e
   # Remove this only on worldtree-dev's word, and then say so in the run notes.
   unset ALBOK_SERVICE ALBOK_TOKEN
   export WORLDTREE_ROOT="$run_tree"
+  export TMPDIR="$scratch_parent"   # the harness's mkdtemp(prefix="wt-tracer-") lands here, and --keep-data keeps it
   # The editable install maps packages/ to the main tree; put the tree under
   # test first (identical content is guaranteed by step 2, this keeps it explicit).
   export PYTHONPATH="$run_tree/packages/worldtree-memory/src${PYTHONPATH:+:$PYTHONPATH}"
@@ -174,11 +186,13 @@ if [[ "$rc" -ne 0 || ! -f "$run_dir/trace1.md" ]]; then
 fi
 
 stamp="$(basename "$run_dir")"
+kept="$(find "$scratch_parent" -mindepth 1 -maxdepth 1 -type d -name 'wt-tracer-*' -print -quit)"
 verdict_line="$(grep -m1 -E '^Aggregate label: .*verdict: \*\*(PASS|FAIL)\*\*' "$run_dir/trace1.md" || true)"
 verdict="$(sed -nE 's/.*verdict: \*\*(PASS|FAIL)\*\*.*/\1/p' <<<"$verdict_line")"
 echo "  run stamp    $stamp"
 echo "  verdict      ${verdict:-NONE}"
 echo "  line         ${verdict_line:-<no Aggregate verdict line in trace1.md>}"
+echo "  kept scratch ${kept:-<none found under $scratch_parent>}   (memory/writer, memory/reader; kept 14 days)"
 case "$verdict" in
   PASS) echo "→ report to worldtree-dev today with run stamp $stamp (PASS builds the n)."; exit 0 ;;
   FAIL) echo "→ report to worldtree-dev TODAY with run stamp $stamp. Do not retry." >&2; exit 1 ;;