From c0231fcd26f503f8c95f2cdd365d75d5217aa772 Mon Sep 17 00:00:00 2001
From: Timothy Farrell <tim@thecookiejar.me>
Date: Fri, 15 May 2026 21:07:09 +0000
Subject: [PATCH] Add the AGENTs file to cut down on model code analysis

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 AGENTS.md | 72 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 72 insertions(+)
 create mode 100644 AGENTS.md

diff --git a/AGENTS.md b/AGENTS.md
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+# Password Vault — Agent Context
+
+## Project Overview
+
+An offline-first, single-file password manager built with **Svelte 5** (runes-based reactivity). All data is encrypted in-browser with AES-256-GCM and stored in IndexedDB. The production build is a single `dist/index.html` with zero network dependencies — it works from `file://`, USB, or any static server.
+
+## Architecture
+
+```
+src/
+├── App.svelte                  # Root component — routes between LockScreen, MainLayout
+├── main.js                     # Entry point
+├── components/
+│   ├── LockScreen.svelte       # Master password setup + unlock UI
+│   ├── MainLayout.svelte       # Shell: sidebar + content area
+│   ├── Sidebar.svelte          # Group list + search bar
+│   ├── EntryList.svelte        # Credential entries grid
+│   ├── EntryForm.svelte        # Create/edit credential form
+│   ├── EntryDetail.svelte      # View single entry (copy password/username)
+│   ├── PasswordGenerator.svelte# Configurable password generator
+│   └── ImportExport.svelte     # JSON import/export with merge/replace
+├── lib/
+│   ├── crypto/crypto.js        # Web Crypto API: PBKDF2 key derivation, AES-GCM encrypt/decrypt, password generator
+│   ├── storage/db.js           # IndexedDB layer (idb wrapper): entries, groups, meta stores
+│   ├── models/schema.js        # Data models: CredentialEntry, Group; validation; ID generation
+│   └── stores/
+│       ├── app.svelte.js       # AppStore: $state(isUnlocked, encryptionKey, salt)
+│       ├── security.svelte.js  # Auto-lock timer, visibility change, beforeunload cleanup
+│       └── search.svelte.js    # Reactive search state
+```
+
+## Key Design Decisions
+
+- **Svelte 5 runes** — Use `$state`, `$derived`, `$effect`. Props-based event passing (no Svelte events).
+- **No external crypto libraries** — Uses the browser's native Web Crypto API exclusively.
+- **Key never persisted** — Encryption key lives only in `$state` memory; cleared on lock, tab switch, or page close.
+- **Single-file build** — `vite-plugin-singlefile` inlines all JS/CSS; post-build script inlines favicon.
+- **IndexedDB via `idb`** — Three stores: `entries`, `groups`, `meta`. Only `encryptedPassword` is encrypted at rest; titles, usernames, URLs, and notes are plaintext for searchability.
+- **PBKDF2 key derivation** — 600,000 iterations, SHA-256, 256-bit AES-GCM key.
+
+## Encryption Flow
+
+```
+Master Password → PBKDF2 (600k iters, 16-byte salt) → AES-256-GCM Key → encrypt/decrypt credentials
+```
+
+Password verification uses a test payload (random string encrypted at vault creation). On unlock, the entered password derives a key that must successfully decrypt the test payload.
+
+## Scripts
+
+| Command | Description |
+|---|---|
+| `npm run dev` | Vite dev server with HMR on `:5173` |
+| `npm run build` | Production build → `dist/index.html` (single self-contained file) |
+| `npm run preview` | Preview production build |
+| `npm run test` | Vitest (watch mode) |
+| `npm run test:run` | Vitest (single run) |
+
+## Testing
+
+- Framework: **Vitest** with **jsdom** environment
+- Test setup: `tests/setup.js` (fake-indexeddb polyfill)
+- Test files: `tests/lib/stores/*.test.js`
+- Run with `npm run test` or `npm run test:run`
+
+## Security Notes
+
+- Only `encryptedPassword` is encrypted at rest; other fields (title, username, URL, notes) are plaintext in IndexedDB.
+- `testPlaintext` for password verification is stored unencrypted in the `meta` store.
+- Auto-lock triggers on tab visibility change and 5-minute inactivity.
+- Clipboard auto-clears after 15 seconds.
+- No browser fingerprinting or anti-keylogger protections.