diff --git a/docs/Disaggregated/notes/p13/tools/w5_classify.py b/docs/Disaggregated/notes/p13/tools/w5_classify.py
index 278b702b..42607a1d 100644
--- a/docs/Disaggregated/notes/p13/tools/w5_classify.py
+++ b/docs/Disaggregated/notes/p13/tools/w5_classify.py
@@ -37,7 +37,9 @@ TRANSPORT = [r'ClientSession', r'ServerSession', r'ServerLoop', r'Transport::',
              r'Transport\s*!=', r'Transport\s*==',
              # Second pass (S2): transport-shaped words that name no MG_Remote symbol.
              r'Window', r'SwapInterval', r'ContextLive', r'Ahb', r'AHardwareBuffer', r'HardwareBuffer', r'[Dd]ma[Bb]uf',
-             r'Gbm', r'SyncFile', r'sync_file', r'Session', r'Peer', r'Spawn', r'Tcp', r'Socket']
+             r'Gbm', r'SyncFile', r'sync_file', r'Session', r'Peer', r'Spawn', r'Tcp', r'Socket',
+             # Device loss and its recovery are a session's (the session ends, not the process).
+             r'Lost', r'Epoch', r'ResetNotif', r'Recover', r'StreamGate', r'ReplacementShare', r'ReplaceProcessDefault']
 RECORD = [r'DataArmIsRecord', r'RecordArm', r'Staged', r'\bWire', r'MGPipe', r'Handle', r'Record\b', r'Twin',
           r'Respecif', r'Readback', r'Verb', r'PersistentMap', r'GpuWrite', r'Emit', r'Applier', r'Slot',
           r'Residual', r'ContextValues', r'Cso\b', r'CSO', r'Placeholder', r'Mipmap', r'Shadow']
diff --git a/docs/Disaggregated/notes/p13/tools/w5_rewrite.py b/docs/Disaggregated/notes/p13/tools/w5_rewrite.py
new file mode 100644
index 00000000..5277faab
--- /dev/null
+++ b/docs/Disaggregated/notes/p13/tools/w5_rewrite.py
@@ -0,0 +1,94 @@
+#!/usr/bin/env python3
+"""P13 W5 S2: move the record arm's guards from MOBILEGL_BUILD_DISAGGREGATED to
+MOBILEGL_BUILD_RECORD_ARM, by w5_classify.py's classes.
+
+  w5_rewrite.py [--root DIR] [--dir PREFIX ...] [--dry-run]
+
+Rewritten (the macro on the opening line, and on its #else / #endif comment if it names it):
+  * a plain `#if MOBILEGL_BUILD_DISAGGREGATED` group of class A or F (record terms or nothing, no
+    transport word, no MG_Remote name);
+  * every plain `#if !MOBILEGL_BUILD_DISAGGREGATED` (the frontend arm of a build without the record arm);
+  * `#if MOBILEGL_PIPE_VERIFY && !MOBILEGL_BUILD_DISAGGREGATED` (the verify tree's frontend pins).
+Left for the hand pass (S3): B, C, D, E and the compound guards; the MOBILEGL_PIPE_POISON arm in
+PipeInputs.h stays on DISAGG on purpose (the FCL library must not pay a per-read poison check).
+Tests (MG_Test, MG_IntegrationTest) are S6's.
+
+While MOBILEGL_BUILD_RECORD_ARM equals MOBILEGL_BUILD_DISAGGREGATED (until S7) every rewrite is a
+no-op for the compiler: both trees keep byte-identical code.
+"""
+import argparse
+import pathlib
+import re
+import sys
+
+sys.path.insert(0, str(pathlib.Path(__file__).parent))
+import w5_classify as wc  # noqa: E402
+
+OLD = 'MOBILEGL_BUILD_DISAGGREGATED'
+NEW = 'MOBILEGL_BUILD_RECORD_ARM'
+SKIP_TOP = ('MobileGL/MG_Test/', 'MobileGL/MG_IntegrationTest/')
+# S2 touches only the trees the record core lives in. The EGL layer, the GL context's device-loss
+# state, the logger's role files and the stats dump paths are session machinery whose guards the
+# token classes cannot tell apart from record code; they are S3's hand pass.
+RECORD_DIRS = ('MobileGL/MG_Backend/DirectGLES/', 'MobileGL/MG_Backend/DirectVulkan/', 'MobileGL/MG_Backend/MGPipe/',
+               'MobileGL/MG_Pipe/', 'MobileGL/MG_Impl/Pipe/', 'MobileGL/MG_Impl/GLImpl/',
+               'MobileGL/MG_State/GLState/BufferState/', 'MobileGL/MG_State/GLState/ProgramState/',
+               'MobileGL/MG_State/GLState/FramebufferState/', 'MobileGL/MG_Util/SelfTest/')
+
+
+def rewrite_file(path, rel, lines):
+    rows = wc.classify(rel, lines)
+    changed = []
+    for g in wc.groups(lines):
+        cond = g['cond']
+        plain = re.fullmatch(r'if\s+' + OLD, cond) is not None
+        negated = re.fullmatch(r'if\s+!\s*' + OLD, cond) is not None
+        verify_pin = re.fullmatch(r'if\s+MOBILEGL_PIPE_VERIFY\s*&&\s*!\s*' + OLD, cond) is not None
+        if plain:
+            cls = next(r['class'] for r in rows if r['open'] == g['open'])
+            if cls not in ('A', 'F'):
+                continue
+        elif not (negated or verify_pin):
+            continue
+        targets = [g['open']] + [no for no, kind in g['branches'][1:]] + [g['close']]
+        for no in targets:
+            line = lines[no - 1]
+            if no == g['open'] or OLD in line:
+                lines[no - 1] = line.replace(OLD, NEW)
+        changed.append((g['open'], 'plain' if plain else 'negated' if negated else 'verify-pin'))
+    return changed
+
+
+def main():
+    ap = argparse.ArgumentParser()
+    ap.add_argument('--root', default='.')
+    ap.add_argument('--dir', action='append', default=[])
+    ap.add_argument('--dry-run', action='store_true')
+    args = ap.parse_args()
+    root = pathlib.Path(args.root)
+    total = 0
+    for p in sorted((root / 'MobileGL').rglob('*')):
+        if p.suffix not in wc.EXTS or not p.is_file():
+            continue
+        rel = p.relative_to(root).as_posix()
+        if wc.SKIP_PARTS & set(pathlib.PurePosixPath(rel).parts) or rel.startswith(SKIP_TOP) or not rel.startswith(RECORD_DIRS):
+            continue
+        if args.dir and not any(rel.startswith(d) for d in args.dir):
+            continue
+        raw = p.read_bytes().decode('utf-8')
+        crlf = '\r\n' in raw
+        lines = raw.replace('\r\n', '\n').splitlines(keepends=True)
+        changed = rewrite_file(p, rel, lines)
+        if not changed:
+            continue
+        total += len(changed)
+        print('%-70s %3d' % (rel, len(changed)))
+        if not args.dry_run:
+            text = ''.join(lines)
+            p.write_bytes((text.replace('\n', '\r\n') if crlf else text).encode('utf-8'))
+    print('groups rewritten:', total)
+    return 0
+
+
+if __name__ == '__main__':
+    sys.exit(main())