aix is a Manifest V3 Chrome extension that injects a fixed export button into Claude and ChatGPT conversation pages, extracts visible turns from live DOM trees, converts them to Markdown, and downloads a local .md file without a background worker, storage layer, or remote service.

• Primary references: Chrome Extensions MV3, Bun docs, Biome docs, tsgo
• Local source-of-truth files: manifest.json, package.json, src/index.ts, src/platforms/claude.ts, src/platforms/chatgpt.ts, src/parsers/markdown.ts
• Regression surface: tests/integration/, tests/parsers/, tests/fixtures/
• Mirror contract: AGENTS.md is canonical; CLAUDE.md and README.md symlink to it

.
├── src/
│   ├── index.ts              content-script entrypoint and export flow
│   ├── platforms/            Claude / ChatGPT detection, selectors, extraction
│   ├── parsers/              DOM -> Markdown conversion and sanitization
│   ├── ui/                   injected button, toast, and styles
│   └── utils/                download, filename, markdown, SPA navigation
├── tests/
│   ├── integration/          fixture-backed export flow coverage
│   ├── fixtures/             synthetic Claude and ChatGPT DOM fixtures
│   └── helpers/              happy-dom factories and fixture loaders
├── assets/                   extension icons copied into dist/
├── dist/                     generated unpacked-extension payload
└── AGENTS.md                 canonical repo instructions

• Start in src/platforms/ for site-compatibility work and in src/parsers/ for markdown fidelity changes
• Treat tests/fixtures/ as the DOM contract and dist/ as generated output

• bun install - install dependencies and Husky hooks
• bun run dev - watch-build only dist/contentScript.js; it does not recopy manifest.json or assets/
• bun run build - produce the full unpacked extension in dist/ with JS, manifest, and icons
• bun run util:lint - read-only Biome lint pass
• bun run util:types - read-only tsgo --noEmit
• bun test --concurrent - run unit and integration tests against fixture DOM
• bun run util:check - write-enabled full gate; runs format, lint, types, and tests

• src/index.ts: detects the host, injects shared styles, retries button insertion, hooks SPA navigation by patching history.pushState / history.replaceState, then executes click -> extract -> compose -> download
• src/platforms/types.ts: PlatformConfig is the only adapter contract; adapters return ordered Message[] plus a derived title
• src/platforms/claude.ts: only activates on /chat/<uuid> routes, prefers .standard-markdown* blocks, extracts artifact cards, reads action-bar timestamps, and backfills missing timestamps across adjacent turns
• src/platforms/chatgpt.ts: accepts full conversation turns or /c/ and /g/ routes, deduplicates nested .markdown / .whitespace-pre-wrap blocks, and turns attached files into Markdown attachment sections
• src/platforms/selectors.ts: centralizes primary and fallback selectors; keep DOM drift isolated here before widening parser logic
• src/parsers/markdown.ts: central DOM -> Markdown dispatcher for paragraphs, headings, lists, tables, blockquotes, code fences, inline code, images, task lists, and separator-based message composition
• src/parsers/sanitizer.ts and src/utils/dom.ts: clone-and-prune hidden or non-content nodes before conversion; ChatGPT intentionally uses a custom selector set that keeps checkbox inputs and role-based images
• src/ui/ and src/utils/download.ts: render a fixed overlay button plus toast, then download via Blob and object URL with no background messaging

• manifest.json injects the content script at document_idle on https://claude.ai/*, https://chatgpt.com/*, and https://chat.openai.com/*
• The extension is stateless at runtime: no Chrome storage, no service worker, no popup UI, and no network fetches in the shipped code
• Markdown metadata uses new Date().toISOString() while filenames use local time in platform-chat-YYYYMMDD-HHMMSS-<slug>.md
• Generated artifacts live under dist/: dist/contentScript.js, dist/manifest.json, and dist/assets/; regenerate them, do not edit by hand
• Ignored scratch space exists under .tmp/, tmp/, temp/, and coverage/; .tmp/ currently contains ad hoc HTML captures and screenshots that are not canonical test inputs
• The existing symlink mirror is intentional: CLAUDE.md and README.md should keep pointing at AGENTS.md

• Use @/ for source imports and @tests/ for test helpers; avoid relative TypeScript imports across the repo
• Keep selector drift in src/platforms/selectors.ts or adapter-local extraction helpers; when a platform DOM changes, add or update fixture coverage first
• Preserve message order and duplicates; Claude timestamp backfill and ChatGPT chunk deduplication are intentional export behaviors
• Avoid depending on console output for debugging outcomes; existing debug logs are tolerated in source but removed from release builds by terser
• Commit messages must satisfy commitlint.config.js: types feat|fix|refactor|docs|style|chore|test, scopes extension|parser|ui|platform|build|deps|docs

• Never hand-edit dist/; bun run dev only refreshes JS and bun run build regenerates the full unpacked extension
• Keep tests/fixtures/ synthetic and reviewable; do not commit full live page captures, auth bootstrap blobs, sidebar history, or other account-scoped DOM dumps
• Do not relax sanitize rules or hidden-node checks without proving exports stay clean on both platforms; they intentionally strip copy controls, system messages, and presentation-only DOM
• Be careful changing src/utils/navigation.ts; it monkey-patches the history API globally and has no teardown path in production code
• Do not rename files in assets/ without updating manifest.json and rebuilding dist/
• Automated tests do not exercise live Chrome injection, CSP behavior, or actual browser downloads; selector and UI work still needs a manual browser smoke test

• Read-only completion gate: bun run util:lint, bun run util:types, bun test --concurrent
• Build gate when changing shipped code, icons, or manifest: bun run build
• Use bun run util:check only when you want the repo reformatted as part of the change; it runs util:format before lint, types, and tests
• If you change src/platforms/ or parser behavior, update fixture-backed coverage in tests/integration/ or tests/parsers/ and keep tests/fixtures/ aligned with the new DOM assumptions
• Manual smoke for platform changes: load dist/ as an unpacked extension, verify the button appears exactly once on one Claude /chat/<uuid> page and one ChatGPT /c/... or /g/... page, then confirm the exported markdown preserves order, code blocks, lists, tables, and attachment or artifact sections
• No CI or GitHub workflow is present in the repository; local validation is the completion bar