diff --git a/docs/marketplace-polyrepo-migration/migration/00-preflight.sh b/docs/marketplace-polyrepo-migration/migration/00-preflight.sh
index 77659a0..2162f7f 100644
--- a/docs/marketplace-polyrepo-migration/migration/00-preflight.sh
+++ b/docs/marketplace-polyrepo-migration/migration/00-preflight.sh
@@ -42,6 +42,21 @@ python3 -c "import json; json.load(open('$MAP'))" >/dev/null 2>&1 || fail "plugi
 TARGET_COUNT="$(python3 -c "import json; print(len(json.load(open('$MAP'))['targets']))")"
 [ "$TARGET_COUNT" = "11" ] || fail "expected 11 targets in plugin-map.json, found $TARGET_COUNT"
 
+# --- path hygiene (aeb6292): every target path must be whitespace- and glob-free, so the space-joined
+#     `for p in $(mappaths …)` word-splitting in 99-dryrun.sh (live_files / SC6 baseline) is sound. ---
+python3 - "$MAP" <<'PY' || fail "plugin-map.json has a path with whitespace or a glob metacharacter (breaks word-split path handling in 99-dryrun.sh)"
+import json, re, sys
+m = json.load(open(sys.argv[1]))
+bad = []
+for k, t in m["targets"].items():
+    for p in t.get("paths", []):
+        if re.search(r"\s", p) or any(c in p for c in "*?[]"):
+            bad.append("%s: %r" % (k, p))
+if bad:
+    sys.stderr.write("offending paths:\n  " + "\n  ".join(bad) + "\n")
+    sys.exit(1)
+PY
+
 # --- repo baseline (HEAD descends from the ratified brief commit, on main, not behind remote) ---
 BRANCH="$(git -C "$REPO_ROOT" rev-parse --abbrev-ref HEAD)"
 [ "$BRANCH" = "main" ] || fail "not on main (HEAD on '$BRANCH')"
diff --git a/docs/marketplace-polyrepo-migration/migration/00-preflight.test.mjs b/docs/marketplace-polyrepo-migration/migration/00-preflight.test.mjs
index 651e31d..bf39a02 100644
--- a/docs/marketplace-polyrepo-migration/migration/00-preflight.test.mjs
+++ b/docs/marketplace-polyrepo-migration/migration/00-preflight.test.mjs
@@ -11,13 +11,18 @@ const map = JSON.parse(readFileSync(join(here, 'plugin-map.json'), 'utf8'));
 const targets = map.targets;
 const keys = Object.keys(targets);
 
-const RENAMED = ['voyage', 'llm-security', 'linkedin-studio'];
+// voyage ← ultraplan-local and linkedin-studio ← linkedin-thought-leadership are TRUE renames, so each
+// carries >=2 --path entries (F1). llm-security is NOT a rename: llm-security-copilot was a SEPARATE,
+// COEXISTING plugin, so llm-security is SINGLE-path (corrected 2026-06-17, commit 836b8e9) — a dual --path
+// there collided at the coexistence commits and dropped 87 files. The map is authoritative; this suite
+// tracks it.
+const RENAMED = ['voyage', 'linkedin-studio'];
 
 test('plugin-map.json parses and has exactly 11 targets (10 plugins + DS)', () => {
   assert.equal(keys.length, 11, `expected 11 targets, found ${keys.length}: ${keys.join(', ')}`);
 });
 
-test('the 3 renamed plugins each carry >=2 --path entries (F1)', () => {
+test('the renamed plugins (voyage, linkedin-studio) each carry >=2 --path entries (F1)', () => {
   for (const k of RENAMED) {
     assert.ok(targets[k], `missing renamed target ${k}`);
     assert.ok(
@@ -27,6 +32,15 @@ test('the 3 renamed plugins each carry >=2 --path entries (F1)', () => {
   }
 });
 
+test('llm-security is SINGLE-path — NOT a rename (copilot was a coexisting plugin, 836b8e9)', () => {
+  // Locks in the 87-file-drop correction: re-introducing a 2nd --path here would re-collide at the
+  // coexistence commits and silently drop files again.
+  assert.equal(
+    targets['llm-security'].paths.length, 1,
+    `llm-security must stay single-path (dual-path dropped 87 files), has ${targets['llm-security'].paths.length}`
+  );
+});
+
 test('every target repo_url is https:// (not ssh://) — F2 / #9740', () => {
   for (const k of keys) {
     assert.match(targets[k].repo_url, /^https:\/\/git\.fromaitochitta\.com\/open\//, `${k} repo_url not the expected HTTPS form`);
diff --git a/docs/marketplace-polyrepo-migration/migration/10-extract.sh b/docs/marketplace-polyrepo-migration/migration/10-extract.sh
index 0c1ba86..e447e03 100644
--- a/docs/marketplace-polyrepo-migration/migration/10-extract.sh
+++ b/docs/marketplace-polyrepo-migration/migration/10-extract.sh
@@ -62,6 +62,12 @@ rm -f "$ARGS_FILE"
 
 TAG="$(python3 -c "import json; print(json.load(open('$MAP'))['targets']['$KEY']['tag'])")"
 
+# Re-assert the critical extension here too: the self-heal above runs preflight ONLY on a missing mirror,
+# so a present mirror + since-uninstalled git-filter-repo would otherwise die with a raw git error instead
+# of this actionable message (9e588ca — RUNBOOK lists it under Preconditions).
+git filter-repo --version >/dev/null 2>&1 \
+  || fail "git filter-repo not available — brew install git-filter-repo (see RUNBOOK Preconditions)"
+
 # Fresh --no-local clone from the mirror, then the single composing filter-repo pass.
 rm -rf "$DEST"
 git clone --no-local --quiet "$MIRROR" "$DEST"
diff --git a/docs/marketplace-polyrepo-migration/migration/40-validate-standalone.sh b/docs/marketplace-polyrepo-migration/migration/40-validate-standalone.sh
index 2ba6e90..622f995 100644
--- a/docs/marketplace-polyrepo-migration/migration/40-validate-standalone.sh
+++ b/docs/marketplace-polyrepo-migration/migration/40-validate-standalone.sh
@@ -78,32 +78,45 @@ validate_target() {
     fi
   fi
 
-  # --- SC2: run the plugin's declared runner in the clean room ---
-  local test_cmd advisory
+  # --- SC2: route to the target's dedicated gate if it declares one, else run the declared runner in the
+  #     clean room. config-audit's full `node --test 'tests/**/*.test.mjs'` FAILs at a fresh-clone path on
+  #     the 6 machine-locked v5.0.0 byte-stability tests — the exact blocker its Step-7 gate resolves — so
+  #     `--all` MUST delegate to that gate (mirroring 99-dryrun.sh), not run the raw test_cmd. ---
+  local test_cmd advisory sc2_gate
   test_cmd="$(python3 -c "import json; print(json.load(open('$MAP'))['targets']['$key'].get('test_cmd',''))")"
   advisory="$(python3 -c "import json; print(json.load(open('$MAP'))['targets']['$key'].get('test_cmd_advisory',''))")"
-
-  # The generic structure validator (Step 7) is referenced by test-less plugins — vendor it into the clean room.
-  case "$test_cmd" in
-    *validate-plugin.generic.sh*)
-      if [ -f "$GENERIC_VALIDATOR" ]; then cp "$GENERIC_VALIDATOR" "$cr/validate-plugin.generic.sh"; fi
-      ;;
-  esac
+  sc2_gate="$(python3 -c "import json; print(json.load(open('$MAP'))['targets']['$key'].get('sc2_gate',''))")"
 
   local sc2_label="standalone-safe"
-  local out status tests
-  out="$(cd "$cr" && eval "$test_cmd" 2>&1)"; status=$?
-  if [ $status -ne 0 ]; then
-    problems="$problems; SC2 runner failed (exit $status)"
+
+  if [ -n "$sc2_gate" ]; then
+    if WORK="$WORK" bash "$SCRIPT_DIR/$sc2_gate" >/dev/null 2>&1; then
+      sc2_label="$sc2_gate, standalone-safe"
+    else
+      problems="$problems; SC2 gate failed ($sc2_gate)"
+    fi
+  else
+    # The generic structure validator (Step 7) is referenced by test-less plugins — vendor it into the clean room.
+    case "$test_cmd" in
+      *validate-plugin.generic.sh*)
+        if [ -f "$GENERIC_VALIDATOR" ]; then cp "$GENERIC_VALIDATOR" "$cr/validate-plugin.generic.sh"; fi
+        ;;
+    esac
+
+    local out status tests
+    out="$(cd "$cr" && eval "$test_cmd" 2>&1)"; status=$?
+    if [ $status -ne 0 ]; then
+      problems="$problems; SC2 runner failed (exit $status)"
+    fi
+    case "$test_cmd" in
+      *node\ --test*)
+        # Node 25's default reporter prints "ℹ tests N"; older/TAP prints "# tests N". Match either.
+        tests="$(printf '%s\n' "$out" | grep -oE 'tests [0-9]+' | grep -oE '[0-9]+' | tail -1)"
+        [ -n "$tests" ] && sc2_label="$tests tests, standalone-safe"
+        ;;
+      *validate-plugin*) sc2_label="structure, standalone-safe" ;;
+    esac
   fi
-  case "$test_cmd" in
-    *node\ --test*)
-      # Node 25's default reporter prints "ℹ tests N"; older/TAP prints "# tests N". Match either.
-      tests="$(printf '%s\n' "$out" | grep -oE 'tests [0-9]+' | grep -oE '[0-9]+' | tail -1)"
-      [ -n "$tests" ] && sc2_label="$tests tests, standalone-safe"
-      ;;
-    *validate-plugin*) sc2_label="structure, standalone-safe" ;;
-  esac
 
   if [ -n "$problems" ]; then
     echo "$key: FAIL${problems}"
diff --git a/docs/marketplace-polyrepo-migration/migration/99-dryrun.sh b/docs/marketplace-polyrepo-migration/migration/99-dryrun.sh
index d69b27d..30ba49b 100644
--- a/docs/marketplace-polyrepo-migration/migration/99-dryrun.sh
+++ b/docs/marketplace-polyrepo-migration/migration/99-dryrun.sh
@@ -49,6 +49,7 @@ mapget() { python3 -c "import json;print(json.load(open('$MAP'))['targets']['$1'
 mappaths() { python3 -c "import json;print(' '.join(json.load(open('$MAP'))['targets']['$1']['paths']))"; }
 
 # Live monorepo git-tracked file count across a target's source paths (SC6 baseline).
+# Paths are asserted whitespace- and glob-free by 00-preflight.sh (aeb6292), so the word-split below is sound.
 live_files() {
   local key="$1" total=0 p n
   for p in $(mappaths "$key"); do
@@ -110,7 +111,11 @@ for key in $KEYS; do
   commits=0; tag="(none)"; ext_files=0; sc7="clean"; sc6="?"
   if [ -d "$dest/.git" ]; then
     commits="$(git -C "$dest" rev-list --count HEAD 2>/dev/null || echo 0)"
-    tag="$(git -C "$dest" tag 2>/dev/null | head -1)"; tag="${tag:-(none)}"
+    # F5 invariant: 10-extract.sh strips all carried-over tags and re-creates EXACTLY one. Assert that —
+    # a partial tag-strip leaves multiple tags, and `head -1` would silently report the lexicographically
+    # -first wrong one (e.g. v1.0.0 instead of v5.1.1) while the dry-run still passed (1708e90).
+    tagn="$(git -C "$dest" tag 2>/dev/null | wc -l | tr -d '[:space:]')"
+    if [ "$tagn" = "1" ]; then tag="$(git -C "$dest" tag 2>/dev/null)"; else tag="(tags=$tagn!)"; ok=0; fi
     ext_files="$(git -C "$dest" ls-files | wc -l | tr -d '[:space:]')"
     leak="$(git -C "$dest" ls-files | grep -E 'STATE\.md|\.local\.md$' \
       | grep -v 'templates/okr\.local\.md\.template' || true)"
@@ -119,14 +124,16 @@ for key in $KEYS; do
     ok=0
   fi
 
-  # SC6 content retention. Intentional blob-strip targets may legitimately shed >1MB blobs, so a drop
-  # there is reported, not failed; for every other target a drop is a hard FAIL (the llm-security class).
+  # SC6 content retention — delegated to sc6-check.sh (the DROP detector, unit-tested in sc-checks.test.mjs).
+  # Only meaningful when the extract succeeded: a failed extract leaves ext_files=0, which must NOT be
+  # mislabelled as a content DROP (8d649e9) — emit (extract failed) instead. An intentional >1MB blob-strip
+  # target may legitimately shed blobs (reported, not failed); a shortfall elsewhere is a hard DROP (ok=0).
   lf="$(live_files "$key")"
   blob="$(mapget "$key" blob_strip)"
-  if [ "$ext_files" -lt "$lf" ]; then
-    if [ "$blob" = "True" ]; then sc6="${ext_files}/${lf} (blob-strip)"; else sc6="${ext_files}/${lf} DROP"; ok=0; fi
+  if [ -d "$dest/.git" ]; then
+    if sc6="$(bash "$SCRIPT_DIR/sc6-check.sh" "$ext_files" "$lf" "$blob")"; then :; else ok=0; fi
   else
-    sc6="${ext_files}/${lf}"
+    sc6="(extract failed)"
   fi
 
   # --- SC2 (regression-relative) ---
@@ -140,15 +147,27 @@ for key in $KEYS; do
     else
       case "$test_cmd" in
         *node\ --test*)
-          # Regression-relative: standalone failing set must be a subset of the in-repo failing set.
-          sf="$(mktemp)"; bf="$(mktemp)"
-          capture_fails "/tmp/claude-$key" "$test_cmd" > "$sf" 2>/dev/null
-          capture_fails "$REPO_ROOT/plugins/$key" "$test_cmd" > "$bf" 2>/dev/null
-          regr="$(comm -23 "$sf" "$bf")"
-          pre="$(wc -l < "$bf" | tr -d '[:space:]')"
-          rm -f "$sf" "$bf"
-          if [ -z "$regr" ]; then sc2="PASS (${pre} pre-existing)"; else
-            sc2="FAIL (regression: $(printf '%s' "$regr" | grep -c .))"; ok=0; fi
+          # Regression-relative: the standalone failing set must be a SUBSET of the in-repo failing set.
+          # Capture the standalone set from the dry-run's OWN prepped extract ($dest = $WORK/$key), NOT the
+          # 40-validate side-effect clean room /tmp/claude-$key (4e494c8 — that implicit coupling masked a
+          # real regression when the dir was absent). Guard mktemp: an empty capture is an ERROR, never a
+          # false zero-regression PASS (4044c49). The subset decision is delegated to sc2-regression.sh.
+          if sf="$(mktemp)" && bf="$(mktemp)"; then
+            capture_fails "$dest" "$test_cmd" > "$sf" 2>/dev/null
+            capture_fails "$REPO_ROOT/plugins/$key" "$test_cmd" > "$bf" 2>/dev/null
+            pre="$(wc -l < "$bf" | tr -d '[:space:]')"
+            if regr="$(bash "$SCRIPT_DIR/sc2-regression.sh" "$sf" "$bf")"; then
+              sc2="PASS (${pre} pre-existing)"
+            else
+              rc=$?
+              if [ "$rc" -ge 2 ]; then sc2="FAIL (sc2-regression error)"; else
+                sc2="FAIL (regression: $(printf '%s' "$regr" | grep -c .))"; fi
+              ok=0
+            fi
+            rm -f "$sf" "$bf"
+          else
+            sc2="FAIL (mktemp)"; ok=0; rm -f "$sf" "$bf"
+          fi
           ;;
         *) sc2="FAIL (structure)"; ok=0 ;;  # deterministic structure check genuinely failed
       esac
diff --git a/docs/marketplace-polyrepo-migration/migration/99-dryrun.test.mjs b/docs/marketplace-polyrepo-migration/migration/99-dryrun.test.mjs
index c62a459..b84943f 100644
--- a/docs/marketplace-polyrepo-migration/migration/99-dryrun.test.mjs
+++ b/docs/marketplace-polyrepo-migration/migration/99-dryrun.test.mjs
@@ -70,6 +70,10 @@ test('llm-security retains all content (SC6 — dual-rename file-drop defect is
   assert.ok(/\bPASS\b/.test(line) && !/FAIL/.test(line), `llm-security must PASS standalone: ${line}`);
 });
 
+// This asserts the HAPPY path (the live report shows no DROP / no regression). The NEGATIVE coverage —
+// proving the SC6 DROP and SC2 regression-FAIL detectors actually FIRE — lives in sc-checks.test.mjs,
+// which drives sc6-check.sh / sc2-regression.sh (the extracted detectors this dry-run calls) directly,
+// because force-fresh re-extraction would undo any file-drop planted into $WORK/<key> here (5d112cb).
 test('no SC6 file-drop and no SC2 regression on any target', { timeout: LONG }, () => {
   const r = report();
   assert.ok(!/\bDROP\b/.test(r), 'no target may drop content (SC6)');
diff --git a/docs/marketplace-polyrepo-migration/migration/RUNBOOK.md b/docs/marketplace-polyrepo-migration/migration/RUNBOOK.md
index f65b5ba..b4346c5 100644
--- a/docs/marketplace-polyrepo-migration/migration/RUNBOOK.md
+++ b/docs/marketplace-polyrepo-migration/migration/RUNBOOK.md
@@ -6,6 +6,9 @@ plus the Step 11 dry-run) was authored and verified locally with **NULL push (D8
 
 ## Preconditions
 
+- **`git-filter-repo`** (a non-default git extension) and **`python3 >= 3.6`** on `PATH` — the extraction
+  (`10-extract.sh`) and every map-driven script depend on them. `00-preflight.sh` and `10-extract.sh`
+  both assert them, but install first: `brew install git-filter-repo python3`.
 - All migration scripts committed locally; the Step 11 dry-run is green (it exercises every script below).
 - `$FORGEJO_TOKEN` is exported (macOS Keychain → `~/.zshenv`) with `write:org` + `repo` scope.
 - The `pre-polyrepo-archive` tag exists locally (D2) — the rollback anchor for the whole operation.
diff --git a/docs/marketplace-polyrepo-migration/migration/plugin-map.json b/docs/marketplace-polyrepo-migration/migration/plugin-map.json
index 4ab5b4c..ab38437 100644
--- a/docs/marketplace-polyrepo-migration/migration/plugin-map.json
+++ b/docs/marketplace-polyrepo-migration/migration/plugin-map.json
@@ -93,7 +93,7 @@
       "repo_url": "https://git.fromaitochitta.com/open/ms-ai-architect.git",
       "has_vendor_ds": true,
       "blob_strip": true,
-      "blob_strip_safe": true,
+      "blob_strip_safe": null,
       "test_cmd": "bash tests/validate-plugin.sh",
       "standalone_caveat": "148 MB screenshot blob-bomb (F3): single filter-repo pass strips >1MB blobs when blob_strip_safe (all under playground/screenshots/), else surgical --path-glob; vendors the design-system"
     },
diff --git a/docs/marketplace-polyrepo-migration/migration/sc-checks.test.mjs b/docs/marketplace-polyrepo-migration/migration/sc-checks.test.mjs
new file mode 100644
index 0000000..f2a62d3
--- /dev/null
+++ b/docs/marketplace-polyrepo-migration/migration/sc-checks.test.mjs
@@ -0,0 +1,92 @@
+// Negative + positive coverage for the two highest-stakes dry-run detectors (5d112cb).
+//
+// 99-dryrun.sh force-fresh re-extracts all 11 targets every run (10-extract.sh wipes $dest first), so a
+// "plant a dropped file in $WORK/<key>" negative test against the full dry-run would be silently undone by
+// the re-extract. So the two load-bearing detectors are extracted into standalone, side-effect-free scripts
+// — sc6-check.sh (the SC6 DROP detector, the guard against the llm-security 87-file-drop class) and
+// sc2-regression.sh (the SC2 regression-FAIL detector) — which 99-dryrun.sh now calls. This suite drives
+// those exact scripts directly, proving each detector FIRES (DROP / regression → label + non-zero exit) and
+// does NOT false-positive (retained content / subset failures → exit 0). When the dry-run calls them and
+// they exit non-zero, it sets ok=0 → exit 1, so the dry-run's "report DROP/regression + exit non-zero"
+// behaviour follows by construction from this coverage.
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import { spawnSync } from 'node:child_process';
+import { mkdtempSync, rmSync, writeFileSync } from 'node:fs';
+import os from 'node:os';
+import path from 'node:path';
+import { fileURLToPath } from 'node:url';
+
+const here = path.dirname(fileURLToPath(import.meta.url));
+const SC6 = path.join(here, 'sc6-check.sh');
+const SC2 = path.join(here, 'sc2-regression.sh');
+
+function run(script, args) {
+  return spawnSync('bash', [script, ...args], { encoding: 'utf8' });
+}
+
+// --- sc6-check.sh — the SC6 DROP detector ---------------------------------------------------------------
+
+test('SC6 DROP fires: a real shortfall (llm-security 87-file class) → DROP label + non-zero exit', () => {
+  const r = run(SC6, ['334', '421', 'false']); // the actual dual-rename defect: 334 of 421 files retained
+  assert.notEqual(r.status, 0, 'a non-blob-strip shortfall must exit non-zero (the dry-run sets ok=0)');
+  assert.match(r.stdout, /334\/421 DROP/, `DROP label expected: ${r.stdout}`);
+});
+
+test('SC6 blob-strip shortfall is allowed: intentional >1MB strip → (blob-strip) label + exit 0', () => {
+  const r = run(SC6, ['100', '200', 'True']); // ms-ai-architect screenshot blob-bomb: legitimate shortfall
+  assert.equal(r.status, 0, `blob-strip shortfall must exit 0: ${r.stderr}`);
+  assert.match(r.stdout, /100\/200 \(blob-strip\)/, `blob-strip label expected: ${r.stdout}`);
+  assert.ok(!/DROP/.test(r.stdout), 'a blob-strip shortfall must NOT be labelled DROP');
+});
+
+test('SC6 retained content: ext == live → no DROP, exit 0', () => {
+  const r = run(SC6, ['421', '421', 'false']);
+  assert.equal(r.status, 0, `full retention must exit 0: ${r.stderr}`);
+  assert.equal(r.stdout.trim(), '421/421');
+});
+
+test('SC6 more files than live (e.g. path-rename overlap) → no DROP, exit 0', () => {
+  const r = run(SC6, ['500', '421', 'false']);
+  assert.equal(r.status, 0);
+  assert.ok(!/DROP/.test(r.stdout), `${r.stdout}`);
+});
+
+// --- sc2-regression.sh — the SC2 regression-FAIL detector -----------------------------------------------
+
+function fixtureFiles(standalone, baseline) {
+  const dir = mkdtempSync(path.join(os.tmpdir(), 'sc2-'));
+  const sf = path.join(dir, 'sf');
+  const bf = path.join(dir, 'bf');
+  writeFileSync(sf, standalone.length ? standalone.join('\n') + '\n' : '');
+  writeFileSync(bf, baseline.length ? baseline.join('\n') + '\n' : '');
+  return { dir, sf, bf };
+}
+
+test('SC2 regression fires: a standalone-only failure (not in baseline) → printed + non-zero exit', () => {
+  // The extraction introduced a NEW failure absent from the in-repo baseline — a real regression.
+  const { dir, sf, bf } = fixtureFiles(['extract regressed test', 'shared pre-existing fail'], ['shared pre-existing fail']);
+  try {
+    const r = run(SC2, [sf, bf]);
+    assert.equal(r.status, 1, `a regression must exit 1 (the dry-run sets ok=0): ${r.stdout}${r.stderr}`);
+    assert.match(r.stdout, /extract regressed test/, `the regressing test name must be reported: ${r.stdout}`);
+  } finally {
+    rmSync(dir, { recursive: true, force: true });
+  }
+});
+
+test('SC2 subset PASS: standalone failures ⊆ baseline (pre-existing red) → exit 0, nothing printed', () => {
+  const { dir, sf, bf } = fixtureFiles(['shared pre-existing fail'], ['shared pre-existing fail', 'other baseline-only fail']);
+  try {
+    const r = run(SC2, [sf, bf]);
+    assert.equal(r.status, 0, `a subset must exit 0 (no migration regression): ${r.stdout}${r.stderr}`);
+    assert.equal(r.stdout.trim(), '', 'no regression should be printed for a subset');
+  } finally {
+    rmSync(dir, { recursive: true, force: true });
+  }
+});
+
+test('SC2 missing capture file is an ERROR (exit 2), never a silent zero-regression PASS (4044c49)', () => {
+  const r = run(SC2, ['/nonexistent/sf', '/nonexistent/bf']);
+  assert.equal(r.status, 2, `a missing capture file must be a hard error, not a false PASS: ${r.stdout}`);
+});
diff --git a/docs/marketplace-polyrepo-migration/migration/sc2-regression.sh b/docs/marketplace-polyrepo-migration/migration/sc2-regression.sh
new file mode 100755
index 0000000..aa4e2ad
--- /dev/null
+++ b/docs/marketplace-polyrepo-migration/migration/sc2-regression.sh
@@ -0,0 +1,20 @@
+#!/usr/bin/env bash
+# SC2 regression decision — extracted from 99-dryrun.sh so the regression-FAIL detector is independently
+# unit-testable (5d112cb). Given two SORTED failing-test-NAME files — the standalone extract's set and the
+# in-repo baseline set — it prints the regressions (standalone failures absent from the baseline) and EXITS
+# NON-ZERO (1) if any exist. The contract: "standalone failing set ⊆ in-repo failing set" (the extraction
+# introduced NO new failure; pre-existing in-repo red is the plugin's own concern, not a migration regr).
+# A missing capture file is a hard ERROR (exit 2), never a silent zero-regression PASS (guards 4044c49).
+#
+# Usage: sc2-regression.sh <standalone_fails_file> <baseline_fails_file>
+set -u
+sf="${1:?standalone fails file}"
+bf="${2:?baseline fails file}"
+[ -f "$sf" ] && [ -f "$bf" ] || { echo "SC2-REGRESSION ERROR: missing capture file ($sf / $bf)" >&2; exit 2; }
+
+regr="$(comm -23 "$sf" "$bf")"
+if [ -n "$regr" ]; then
+  printf '%s\n' "$regr"
+  exit 1
+fi
+exit 0
diff --git a/docs/marketplace-polyrepo-migration/migration/sc6-check.sh b/docs/marketplace-polyrepo-migration/migration/sc6-check.sh
new file mode 100755
index 0000000..7f3ecae
--- /dev/null
+++ b/docs/marketplace-polyrepo-migration/migration/sc6-check.sh
@@ -0,0 +1,23 @@
+#!/usr/bin/env bash
+# SC6 content-retention decision — extracted from 99-dryrun.sh so the DROP detector (the deterministic
+# guard against the llm-security 87-file-drop class, commit 836b8e9) is independently unit-testable
+# (5d112cb). Given the extract's git-tracked file count, the live monorepo's count for the same paths, and
+# whether an intentional >1MB blob-strip applies to this target, it prints the SC6 report-cell label and
+# EXITS NON-ZERO on a real DROP — a shortfall NOT explained by a blob-strip. A blob-strip target may
+# legitimately shed >1MB blobs, so a shortfall there is reported (exit 0), never failed.
+#
+# Usage: sc6-check.sh <ext_files> <live_files> <blob_strip>
+#   blob_strip: True/true → intentional >1MB strip (shortfall allowed); anything else → shortfall = DROP.
+set -u
+ext="${1:?ext_files}"
+live="${2:?live_files}"
+blob="${3:-false}"
+
+if [ "$ext" -lt "$live" ]; then
+  case "$blob" in
+    True|true) echo "${ext}/${live} (blob-strip)"; exit 0 ;;
+    *)         echo "${ext}/${live} DROP";         exit 1 ;;
+  esac
+fi
+echo "${ext}/${live}"
+exit 0