Diff Kernel Profile Archives

Compare the actual contents of two Kernel browser profiles to identify state differences that could explain a reported issue. The skill downloads both profile archives via the Kernel CLI, decompresses them, and produces a structured diff focused on the surfaces most likely to drive divergent behavior: cookies, local/session storage, preferences, extension state, login data, and history.

Inputs

The user must provide:

Profile A — the "baseline" or "working" profile (ID or name)
Profile B — the "subject" or "broken" profile (ID or name)
Issue description — what's happening on B that isn't happening on A (e.g. "login flow on chase.com fails on profile B but works on A", "datadome challenge always fires on B but never on A", "saved credentials missing")

If any of these are missing, prompt for them before proceeding. The issue description is critical — it determines which surfaces of the profile to weight heavily in the diff.

Prerequisites

Kernel CLI installed and authenticated (kernel auth status)
KERNEL_API_KEY set, or the user is logged in via kernel auth login
zstd, tar, sqlite3, and jq available (install via apt-get install -y zstd sqlite3 jq if needed)
~500MB free disk space per profile (profiles can be large)

Workflow

Step 1: Set up workspace

WORKDIR=$(mktemp -d -t profile-diff-XXXXXX)
cd "$WORKDIR"
mkdir -p a b diff
echo "Workspace: $WORKDIR"

Step 2: Download both archives

# Replace <A> and <B> with the profile IDs or names from the user
kernel profiles download <A> --pretty --to a/profile.zip
kernel profiles download <B> --pretty --to b/profile.zip

--pretty pretty-prints JSON files (e.g. Preferences) so they diff cleanly line-by-line. Always pass it.

Step 3: Extract

The archive is Zstandard-compressed TAR despite the .zip extension. Standard unzip will fail.

for side in a b; do
  zstd -d "$side/profile.zip" -o "$side/profile.tar"
  tar -xf "$side/profile.tar" -C "$side"
  rm "$side/profile.tar"
done

After extraction each side typically contains a Chrome user-data-dir layout (e.g. Default/ with Cookies, Local Storage/, Preferences, etc.). If the layout differs, run find a -maxdepth 3 -type d to orient yourself before continuing.

Step 4: Triage by issue description

Pick the surfaces to compare based on what the user described. Don't compare everything — full Chrome profiles contain hundreds of files, most irrelevant. Use this routing:

Issue keywords	Compare these first
login, signed in, session, "logged out"	Cookies, Session Storage, Login Data, Local Storage
SPA / single-page app login (any URL with `#/...` route)	Session Storage first, then Local Storage, then Cookies — SPAs commonly persist auth state in `sessionStorage` rather than cookies
captcha, datadome, cloudflare, akamai, challenge, blocked	Cookies (vendor-specific names), Local Storage, fingerprinting indicators in Preferences
extension, plugin, content script	`Extensions/`, `Local Extension Settings/`, `Extension State`, `Secure Preferences`
autofill, saved password, credential	Login Data, Login Data For Account, Web Data
settings, language, timezone, UA, viewport	Preferences, Secure Preferences
history, cache, "remembers"	History, Top Sites, Visited Links
storage, indexeddb, quota	Local Storage, Session Storage, IndexedDB, Service Worker
profile saved before post-login bootstrap finished (save-time race)	Session Storage (sentinel keys absent), Local Storage analytics events as a bootstrap-timing tracer (e.g. Mixpanel `User Login`, Segment `track`)

When in doubt, start with Cookies + Session Storage + Local Storage + Preferences — they explain the majority of "works on A, fails on B" issues. For SPA-style sites that route via URL hash (/#/...), put Session Storage first: the in-tab auth often lives there, and cookies alone won't tell the story.

Step 5: Run focused diffs

Cookies (SQLite)

Modern Chrome (post-v80) encrypts cookie bodies into encrypted_value and leaves value empty. Always select length(encrypted_value) — length(value) will return 0 for every row and mask real differences.

for side in a b; do
  # Cookies live under Default/Cookies (or Default/Network/Cookies on newer Chrome)
  COOKIE_DB=$(find "$side" -name 'Cookies' -not -name '*-journal' | head -1)
  if [ -z "$COOKIE_DB" ]; then
    echo "(no Cookies DB)" > "diff/cookies-$side.txt"
    continue
  fi
  sqlite3 "$COOKIE_DB" \
    "SELECT host_key, name, length(encrypted_value), is_secure, is_httponly, samesite, expires_utc, source_scheme
     FROM cookies ORDER BY host_key, name;" \
    > "diff/cookies-$side.txt" 2>/dev/null || echo "(cookies query failed)" > "diff/cookies-$side.txt"
done
diff -u diff/cookies-a.txt diff/cookies-b.txt > diff/cookies.diff || true

For issue-relevant hosts only:

HOST=chase.com  # adapt to the issue
for side in a b; do
  sqlite3 "$(find $side -name Cookies -not -name '*-journal' | head -1)" \
    "SELECT host_key, name, length(encrypted_value), expires_utc, is_secure, is_httponly
     FROM cookies WHERE host_key LIKE '%$HOST%' ORDER BY host_key, name;" \
    > "diff/cookies-$HOST-$side.txt"
done
diff -u "diff/cookies-$HOST-a.txt" "diff/cookies-$HOST-b.txt" || true

Common bot-detection cookie names to flag if present in one and not the other: _abck, bm_sz, bm_sv (Akamai); __cf_bm, cf_clearance (Cloudflare); datadome (DataDome); _px*, pxvid (HUMAN/PerimeterX); incap_ses_*, visid_incap_*, reese84 (Imperva).

Preferences (JSON)

for side in a b; do
  PREF=$(find "$side" -name 'Preferences' -not -path '*/Extension*' | head -1)
  if [ -z "$PREF" ]; then
    echo "(no Preferences)" > "diff/preferences-$side.json"
    continue
  fi
  # Already pretty-printed thanks to --pretty
  cp "$PREF" "diff/preferences-$side.json"
done
diff -u diff/preferences-a.json diff/preferences-b.json > diff/preferences.diff || true

Highlight any differences in: intl.* (locale, accept_languages), profile.default_content_setting_values, webrtc.*, extensions.settings (set of installed extensions), dns_over_https.*, download.*, safebrowsing.*.

Local Storage (LevelDB)

ls -la on Local Storage/leveldb/ only tells you whether the dir exists. To actually inspect keys and values without writing a LevelDB reader, run strings on the *.log and *.ldb files — Chrome stores keys and most string values in plaintext inside leveldb, so strings | grep gets you 90% of the way for free.

for side in a b; do
  LS_DIR=$(find "$side" -type d -name 'Local Storage' -not -path '*/Extension*' | head -1)
  if [ -z "$LS_DIR" ]; then
    echo "(no Local Storage)" > "diff/localstorage-files-$side.txt"
    echo "(no Local Storage)" > "diff/localstorage-origins-$side.txt"
    echo "(no Local Storage)" > "diff/localstorage-signals-$side.txt"
    continue
  fi
  # File inventory
  ls -la "$LS_DIR/leveldb" > "diff/localstorage-files-$side.txt" 2>&1
  # All origins that have any data
  strings "$LS_DIR"/leveldb/*.{log,ldb} 2>/dev/null \
    | grep -oE 'META:https?://[^[:space:]]+|^_https?://[^[:space:]^]+' \
    | sort -u > "diff/localstorage-origins-$side.txt"
  # Key inventory per matching origin (adapt grep to the issue host)
  strings "$LS_DIR"/leveldb/*.{log,ldb} 2>/dev/null \
    | grep -aE '"event"|"User Login"|"track"|sessionGUID|authCookie|expirationDateTime|access_token|id_token|refresh_token' \
    | head -100 > "diff/localstorage-signals-$side.txt"
done
diff -u diff/localstorage-files-a.txt diff/localstorage-files-b.txt || true
diff -u diff/localstorage-origins-a.txt diff/localstorage-origins-b.txt || true
diff -u diff/localstorage-signals-a.txt diff/localstorage-signals-b.txt || true

Analytics events as a bootstrap-timing tracer. For SPA logins it's worth grepping the localStorage *.log for embedded analytics queues — Mixpanel writes JSON event blobs (mp_<token>_mixpanel) inline, Segment writes _seg_uid, GA writes _ga. The presence/absence of a User Login, Authenticated, or Identify event in the JSON tells you whether the SPA actually finished its post-login init before the profile snapshot was taken. Last event in the queue ≈ last point the SPA reached. If the broken profile's tail event is View 2FA and the working profile's tail event is User Login, the broken profile was saved mid-flight.

# Mixpanel example: pull the last few events from each side
for side in a b; do
  LS_DIR=$(find "$side" -type d -name 'Local Storage' -not -path '*/Extension*' | head -1)
  if [ -z "$LS_DIR" ]; then
    echo "(no Local Storage)" > "diff/mp-events-$side.txt"
    continue
  fi
  strings "$LS_DIR"/leveldb/*.{log,ldb} 2>/dev/null \
    | grep -oE '"event":"[^"]+"|"Last Login":"[^"]+"|"Timestamp":"[^"]+"' \
    | tail -20 > "diff/mp-events-$side.txt"
done
diff -u diff/mp-events-a.txt diff/mp-events-b.txt || true

For surgical deeper inspection, use a real LevelDB reader (e.g. npx -y level-ls or a small Node script with level package).

Session Storage (LevelDB)

For SPAs (sites that route via URL hash like app.example.com/#/home), the in-tab auth state typically lives in sessionStorage rather than cookies — keys like authCookie, expirationDateTime, sessionGUID, access_token, account/tenant GUIDs, etc. If the saved profile is missing these for the auth origin, the app boots, sees no session in sessionStorage, and bounces to login even though cookies are intact. This is a common failure mode when a profile is snapshotted before the post-login SPA bootstrap finishes.

Chrome serializes sessionStorage namespaces as map-N-<key> entries keyed off a per-tab namespace UUID (namespace-<uuid>-<origin>). The exact N varies by tab navigation history but Chrome restores the namespace→map binding on profile load, so different map-N numbers between profiles are fine — what matters is whether the keys exist at all for the origin in question.

for side in a b; do
  SS_DIR=$(find "$side" -type d -name 'Session Storage' -not -path '*/Extension*' | head -1)
  if [ -z "$SS_DIR" ]; then
    echo "(no Session Storage)" > "diff/sessionstorage-keys-$side.txt"
    echo "(no Session Storage)" > "diff/sessionstorage-namespaces-$side.txt"
    continue
  fi
  # Inventory all map-N-* keys (the actual session storage entries)
  strings "$SS_DIR"/*.{log,ldb} 2>/dev/null \
    | grep -oE 'map-[0-9]+-[A-Za-z._0-9-]+' \
    | sort -u > "diff/sessionstorage-keys-$side.txt"
  # Origin → namespace UUID mappings (so you know which map-N belongs to which site)
  strings "$SS_DIR"/*.{log,ldb} 2>/dev/null \
    | grep -oE 'namespace-[a-f0-9-]+-https?://[^/[:space:]]+' \
    | sort -u > "diff/sessionstorage-namespaces-$side.txt"
done
diff -u diff/sessionstorage-keys-a.txt diff/sessionstorage-keys-b.txt || true
diff -u diff/sessionstorage-namespaces-a.txt diff/sessionstorage-namespaces-b.txt || true

Look for missing auth-shaped keys on the broken side: authCookie, expirationDateTime, sessionGUID, userGuid*, userEmail, *_token, access_token, id_token, anything that looks like an account/tenant/org GUID. If the working side has a cluster of these and the broken side has only the pre-login subset (e.g. just __mplss_* Mixpanel session keys and no auth keys), the snapshot was taken too early.

IndexedDB

for side in a b; do
  IDB_DIR=$(find "$side" -type d -name 'IndexedDB' -not -path '*/Extension*' | head -1)
  if [ -z "$IDB_DIR" ]; then
    echo "(no IndexedDB)" > "diff/idb-$side.txt"
    echo "(no IndexedDB)" > "diff/idb-sizes-$side.txt"
    continue
  fi
  # Per-origin database directories
  ls -la "$IDB_DIR" > "diff/idb-$side.txt" 2>&1
  # Sizes per origin (large delta = significant state delta)
  du -sk "$IDB_DIR"/* 2>/dev/null | sort -rn > "diff/idb-sizes-$side.txt"
  # Cheap content inventory via strings
  for db in "$IDB_DIR"/*.indexeddb.leveldb; do
    [ -d "$db" ] || continue
    origin=$(basename "$db" .indexeddb.leveldb)
    strings "$db"/*.{log,ldb} 2>/dev/null \
      | grep -aE '"name"|"id"|token|user|session|auth' \
      | head -40 > "diff/idb-$origin-$side.txt"
  done
done
diff -u diff/idb-a.txt diff/idb-b.txt || true
diff -u diff/idb-sizes-a.txt diff/idb-sizes-b.txt || true

Most sites use IndexedDB for caches and queued telemetry — but some auth flows (Firebase Auth, Clerk, certain SaaS apps) park session tokens here. Worth a glance whenever sessionStorage/localStorage don't explain the diff.

Extensions

for side in a b; do
  EXT_DIR=$(find "$side" -type d -name 'Extensions' -not -path '*/Local Extension*' | head -1)
  if [ -n "$EXT_DIR" ]; then
    ls "$EXT_DIR" > "diff/extensions-$side.txt"
  else
    echo "(no Extensions dir)" > "diff/extensions-$side.txt"
  fi
done
diff -u diff/extensions-a.txt diff/extensions-b.txt || true

Extension IDs are 32-char hashes. To map an ID to a name, read its manifest.json inside Extensions/<id>/<version>/manifest.json.

Login Data (SQLite)

for side in a b; do
  LOGIN_DB=$(find "$side" -name 'Login Data' -not -name '*-journal' | head -1)
  sqlite3 "$LOGIN_DB" \
    "SELECT origin_url, length(username_value) > 0 AS has_user, length(password_value) AS pw_len, date_created
     FROM logins ORDER BY origin_url;" \
    > "diff/logins-$side.txt" 2>/dev/null || echo "(no Login Data)" > "diff/logins-$side.txt"
done
diff -u diff/logins-a.txt diff/logins-b.txt || true

Never print password_value or username_value — only emit lengths/booleans. Saved credentials are sensitive even in a debugging context.

Top-level inventory (catch unexpected differences)

for side in a b; do
  (cd "$side" && find . -type f -printf '%P\n' | sort) > "diff/files-$side.txt"
done
diff -u diff/files-a.txt diff/files-b.txt > diff/files.diff || true

This catches surprises: a file present in one profile and missing in the other (e.g. Service Worker/ data, IndexedDB/ databases, Trust Tokens, etc.).

Step 6: Synthesize findings

Tie each observed difference back to the issue description. Don't dump raw diffs at the user — interpret. Suspect any of these as likely root causes:

Auth cookie/session token present on A, missing/expired on B → session not established or evicted.
Cookies match between A and B but sessionStorage auth keys (e.g. authCookie, expirationDateTime, sessionGUID, *Guid*, access_token) are missing on B → snapshot was taken before the SPA finished its post-login bootstrap. Classic save-time race: URL flipped to the post-login route, profile got saved, SPA hadn't yet hydrated sessionStorage. On the next session the SPA boots, sees cookies but no in-tab session state, and bounces to login.
localStorage analytics event tail differs (e.g. broken profile's last Mixpanel event is a mid-flow step like a 2FA prompt, working profile's last event is User Login / Authenticated / Identify) → confirms the snapshot timing is the issue, regardless of which storage layer holds the auth.
Bot-detection vendor cookie (_abck, datadome, cf_clearance) only on one side → the "good" profile already cleared the challenge; the other will be re-challenged.
intl.accept_languages or intl.selected_languages differs → server-side localization or geo heuristics will branch.
Extension installed on one side but not the other → ad blocker, anti-fingerprint, or password manager altering page behavior.
webrtc.ip_handling_policy differs → WebRTC IP leak posture changes, can flip fingerprints.
safebrowsing or dns_over_https differs → request-path differences.
Login Data row present on A, absent on B → autofill won't fire on B.
Local Storage origin has keys on A but not B → site-managed session state (JWT in localStorage, feature flags, A/B bucket) won't apply.
IndexedDB database for an auth origin (Firebase, Clerk, etc.) is empty on B but populated on A → SDK token cache absent; client will re-auth or fail.

Step 7: Report

Use this template:

## Profile Diff: <A> vs <B>

### Issue
<one-line restatement of the user's issue description>

### Likely root causes (ranked)
1. **<finding>** — <evidence: which file, which keys/rows> — <why this could cause the issue>
2. **<finding>** — ...
3. **<finding>** — ...

### Other notable differences (probably unrelated)
- <finding>
- <finding>

### Surfaces that matched (for completeness)
- Cookies for <host>: identical
- Preferences `intl.*`: identical
- Extensions installed: identical
- ...

### Suggested next steps
- <e.g. "re-run the failing flow on profile A with a fresh CDP session and capture the request that sets `_abck` — that cookie is the differentiator">
- <e.g. "delete profile B's `Default/Network/Cookies` rows for chase.com and retry — if the flow now works, the stale cookie was the issue">

Step 8: Cleanup

Profile archives can contain credentials. Always remove the workspace when done:

rm -rf "$WORKDIR"

If the user wants to keep the artifacts for further investigation, tell them the path and let them remove it themselves.

Notes & gotchas

Archive format: .zip extension is misleading — it's zstd-compressed TAR. Use zstd -d then tar -xf, not unzip.
--pretty is mandatory for meaningful JSON diffs. Without it, Preferences is a single line and diffs are unreadable.
Chrome profile path varies: most data lives under Default/, but newer Chrome moved cookies to Default/Network/Cookies. Use find instead of hardcoding paths.
SQLite locks: profiles are downloaded as snapshots, so DBs aren't locked — but if a query errors with "database is locked", make sure you're querying the extracted copy, not a path inside an open archive.
Don't compare Cache/, Code Cache/, GPUCache/, Service Worker/CacheStorage/ — these are noise and will produce huge meaningless diffs.
encrypted_value vs value: Chrome encrypts cookie bodies into encrypted_value post-v80. Always select length(encrypted_value) from the cookies table — length(value) returns 0 for every row on modern profiles.
map-N numbers in Session Storage are non-deterministic across profiles — they're per-tab namespace IDs. Don't flag a difference like "auth keys are on map-1- in profile A and map-5- in profile B" as a problem. What matters is whether the keys exist at all for the namespace-<uuid>-<origin> you care about. Chrome restores the namespace→map binding when the profile is loaded.
Apex vs subdomain cookies/storage: a site might set cookies on .example.com (covers all subdomains) but write sessionStorage on app.example.com only. Always check both find $side -name Cookies and the per-origin Local/Session Storage entries for both the apex and the relevant subdomain.
Privacy: never echo cookie values, password fields, or Login Data user/password columns into the report. Use lengths, presence booleans, and host/name only.

diff-profile-archives