LevelDB Operations Skill

LevelDB Operations

Read and decode LevelDB stores — primarily the Chromium/Electron storage layers (Local Storage, IndexedDB, Session Storage) used by every Electron app on disk: Claude Desktop, VS Code, Discord, Slack, Obsidian.

What is LevelDB

Embedded key-value store by Google. Sorted KV map, no SQL, no server. Format: a folder of .ldb (sorted runs), .log (write-ahead), MANIFEST-*, CURRENT, LOCK. Both keys and values are arbitrary bytes.

Chromium layers richer formats on top:

Local Storage — flat key→string map, scoped per origin. Easiest to read.
Session Storage — same shape, per-tab.
IndexedDB — per-origin databases with object stores, indexes, versioned schemas. Encoded with v8 serialization. Needs a real reader.

When This Skill Triggers

"What's in the Local Storage of <Electron app>"
"Decode IndexedDB" / "read .ldb files"
"Why does the sidebar show X" / "where does the desktop app cache Y"
"Reset / mutate Electron app state"
Forensic-style probes of Chrome/Edge/Brave/Electron state

Critical Safety Protocol

LevelDB uses an exclusive LOCK file. A running app holds it. Trying to open a live store fails OR silently returns stale snapshots.

Always copy before reading:

# Copy the entire leveldb dir to a temp location
cp -r "$APPDATA/Claude/Local Storage/leveldb" /tmp/probe/local-storage-db
cp -r "$APPDATA/Claude/IndexedDB/https_claude.ai_0.indexeddb.leveldb" /tmp/probe/indexeddb

# Remove the copied LOCK file so the reader can open it
rm -f /tmp/probe/local-storage-db/LOCK /tmp/probe/indexeddb/LOCK

The cp -r will warn Device or resource busy for the LOCK file itself — that's fine, the data files copy successfully.

Never write to the live store while the app is running. It will corrupt the LSM and crash the app. Quit the app first if you need to mutate.

Setup

plyvel and similar require native compilation and lack Windows wheels. Use ccl_chromium_reader — pure Python, written for browser forensics.

uv venv .venv --python 3.13
source .venv/Scripts/activate          # or .venv/bin/activate on Unix
uv pip install "git+https://github.com/cclgroupltd/ccl_chrome_indexeddb.git"

Not on PyPI — install direct from GitHub. Pulls in ccl-simplesnappy and brotli as transitive deps.

Reading Local Storage

Storage keys are origin URLs (https://claude.ai). Records are append-only — duplicate script_key entries mean older versions; the last record wins.

import pathlib
from ccl_chromium_reader import ccl_chromium_localstorage

ls = ccl_chromium_localstorage.LocalStoreDb(pathlib.Path("./local-storage-db"))

# List all origins
for origin in sorted(set(ls.iter_storage_keys())):
    print(origin)

# Dump one origin, latest-value-wins
latest = {}
for rec in ls.iter_records_for_storage_key("https://claude.ai"):
    latest[rec.script_key] = rec.value
for k, v in latest.items():
    print(f"{k}: {repr(v)[:200]}")

See scripts/dump_localstorage.py for the full reusable script.

Reading IndexedDB

IndexedDB is more complex — wrapped object stores with v8-serialized values. ccl_chromium_reader parses it cleanly:

from ccl_chromium_reader import ccl_chromium_indexeddb

db = ccl_chromium_indexeddb.WrappedIndexDB(pathlib.Path("./indexeddb"))
for db_id in db.database_ids:
    wdb = db[db_id.dbid_no]
    print(f"DB: {wdb.name}")
    for store_name in wdb.object_store_names:
        store = wdb[store_name]
        for rec in store.iterate_records():
            print(f"  {rec.key!r} -> {repr(rec.value)[:200]}")

See scripts/dump_indexeddb.py.

Common Chromium Storage Locations

| OS | Path | |----|------| | Windows | %APPDATA%\<App>\Local Storage\leveldb\ | | Windows | %APPDATA%\<App>\IndexedDB\https_<host>_0.indexeddb.leveldb\ | | macOS | ~/Library/Application Support/<App>/Local Storage/leveldb/ | | Linux | ~/.config/<App>/Local Storage/leveldb/ |

For raw browsers, <App> is Google/Chrome/User Data/Default, BraveSoftware/Brave-Browser/User Data/Default, etc.

Mutation (Advanced)

Writing requires either:

Quitting the app and using a leveldb writer (Node level package, or rebuild the dir manually) — or
Patching via the app itself — many Electron apps expose DevTools. Open with the --remote-debugging-port=<n> flag, attach, and call localStorage.setItem(key, value). Survives the app's normal write path so it doesn't corrupt the LSM.

For Claude Desktop specifically, see references/claude-desktop-state.md for the discovered key map.

Decision Framework

| You want to | Do | |-------------|-----| | Just see what's there | Copy + ccl_chromium_reader | | Find a specific value | strings + grep first; reader if structure matters | | Mutate while app runs | Don't. Use DevTools remote debugging. | | Mutate while app is closed | Quit, then Node level package or write back via re-opened leveldb | | Cross-account recovery | Read-only forensics; can't impersonate server-bound entries |

Anti-patterns

Opening the live store directly → silently stale or open errors
Forgetting to remove LOCK from copy → reader fails
Trusting first hit on a key → leveldb is append-only; iterate all and keep the last
Using strings for structured analysis → misses keys, conflates duplicates, can't distinguish origins
Writing while app runs → LSM corruption, app crash, possible data loss

Reference

scripts/dump_localstorage.py — full Local Storage dump
scripts/dump_indexeddb.py — full IndexedDB dump
scripts/extract_keys.py — targeted key extraction with latest-wins
references/claude-desktop-state.md — Claude Desktop state map (storage keys, sidebar, sessions, account binding)
references/chromium-format.md — leveldb on-disk format, locking, append semantics
ccl_chromium_reader: https://github.com/cclgroupltd/ccl_chrome_indexeddb
LevelDB spec: https://github.com/google/leveldb/blob/main/doc/impl.md

Agent Skills: LevelDB Operations

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