Add CLAUDE.md and README.md documentation

CLAUDE.md

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+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+Android Action Kernel — an AI agent that controls Android devices through the Accessibility API. It runs a Perception → Reasoning → Action loop: captures the screen state via `uiautomator dump`, sends it to an LLM for decision-making, and executes the chosen action via ADB.
+
+**Runtime:** Bun (TypeScript, ES2022 modules). Bun natively loads `.env` files — no dotenv needed.
+
+## Commands
+
+All commands run from `android-action-kernel/`:
+
+```bash
+bun install                    # Install dependencies
+bun run src/kernel.ts          # Start the agent (interactive, prompts for goal)
+bun run build                  # Compile to dist/ (bun build --target bun)
+bun run typecheck              # Type-check only (tsc --noEmit)
+```
+
+There are no tests currently.
+
+## Architecture
+
+Six source files in `android-action-kernel/src/`, no subdirectories:
+
+- **kernel.ts** — Entry point and main agent loop. Reads goal from stdin, runs up to MAX_STEPS iterations of: capture screen → diff with previous → call LLM → execute action → track history. Handles stuck-loop detection and vision fallback when the accessibility tree is empty.
+- **actions.ts** — 15 action implementations (tap, type, enter, swipe, home, back, wait, done, longpress, screenshot, launch, clear, clipboard_get, clipboard_set, shell). Each wraps ADB commands via `Bun.spawnSync()`. `runAdbCommand()` provides exponential backoff retry.
+- **llm-providers.ts** — LLM abstraction with `LLMProvider` interface and factory (`getLlmProvider()`). Four providers: OpenAI, Groq (OpenAI-compatible endpoint), AWS Bedrock (Anthropic + Meta model formats), OpenRouter (Vercel AI SDK). Contains the full SYSTEM_PROMPT with all 15 action definitions and rules.
+- **sanitizer.ts** — Parses Android Accessibility XML (via `fast-xml-parser`) into `UIElement[]`. Depth-first walk extracting bounds, center coordinates, state flags (enabled, checked, focused, etc.), and parent context. `computeScreenHash()` used for stuck-loop detection.
+- **config.ts** — Singleton `Config` object reading from `process.env` with defaults from constants. `Config.validate()` checks required API keys at startup.
+- **constants.ts** — All magic values: ADB keycodes, swipe coordinates (hardcoded for 1080px-wide screens), default models, file paths, agent defaults.
+
+## Key Patterns
+
+- **Provider factory:** `getLlmProvider()` returns the appropriate `LLMProvider` based on `Config.LLM_PROVIDER`. Groq reuses the `OpenAIProvider` class with a different base URL.
+- **Screen state diffing:** Hash-based comparison (id + text + center + state). After STUCK_THRESHOLD unchanged steps, recovery hints are injected into the LLM prompt.
+- **Vision fallback:** When `getInteractiveElements()` returns empty (custom UI, WebView, Flutter), a screenshot is captured and the LLM gets a fallback context suggesting coordinate-based taps.
+- **LLM response parsing:** `parseJsonResponse()` handles both clean JSON and markdown-wrapped code blocks. Falls back to "wait" action on parse failure.
+- **Long press via swipe:** Implemented as `input swipe x y x y 1000` (swipe from point to same point with long duration).
+- **Text escaping for ADB:** Spaces become `%s`, shell metacharacters are backslash-escaped in `executeType()`.
+
+## Adding a New LLM Provider
+
+1. Implement `LLMProvider` interface in `llm-providers.ts`
+2. Add case to `getLlmProvider()` factory
+3. Add config fields to `config.ts` and env vars to `.env.example`
+
+## Adding a New Action
+
+1. Add fields to `ActionDecision` interface in `actions.ts`
+2. Implement `executeNewAction()` function
+3. Add case to `executeAction()` switch
+4. Document the action JSON format in `SYSTEM_PROMPT` in `llm-providers.ts`
+
+## Environment Setup
+
+Requires: Bun 1.0+, ADB (Android SDK Platform Tools) in PATH, an Android device connected via USB/WiFi with accessibility enabled, and an API key for at least one LLM provider (Groq, OpenAI, Bedrock, or OpenRouter).
+
+Copy `.env.example` to `.env` and configure `LLM_PROVIDER` + the corresponding API key.
+
+## Device Assumptions
+
+Swipe coordinates in `constants.ts` are hardcoded for 1080px-wide screens (center X=540, center Y=1200). Adjust `SWIPE_COORDS` and `SCREEN_CENTER_*` for different resolutions.

android-action-kernel/README.md

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+# Android Action Kernel
+
+AI agent that controls Android devices through the Accessibility API. Give it a goal in plain English and it autonomously navigates the device using a Perception → Reasoning → Action loop.
+
+## How It Works
+
+1. **Perceive** — Captures the screen's accessibility tree via `adb shell uiautomator dump`, parses it into interactive UI elements with coordinates and state
+2. **Reason** — Sends the screen context, action history, and goal to an LLM which decides the next action as a JSON object
+3. **Act** — Executes the action (tap, type, swipe, launch app, etc.) via ADB
+4. **Repeat** — Diffs the screen state, detects stuck loops, and continues until the goal is done or max steps reached
+
+Falls back to screenshot-based vision when the accessibility tree is empty (games, WebViews, Flutter).
+
+## Prerequisites
+
+- [Bun](https://bun.sh) 1.0+
+- [Android SDK Platform Tools](https://developer.android.com/tools/releases/platform-tools) (ADB in PATH)
+- Android device connected via USB or WiFi ADB
+- API key for one of: Groq, OpenAI, AWS Bedrock, or OpenRouter
+
+## Quick Start
+
+```bash
+cd android-action-kernel
+bun install
+cp .env.example .env
+# Edit .env — set LLM_PROVIDER and the corresponding API key
+bun run src/kernel.ts
+```
+
+The agent will prompt you for a goal, then start controlling the device.
+
+## Configuration
+
+Copy `.env.example` to `.env`. Key settings:
+
+| Variable | Default | Description |
+|---|---|---|
+| `LLM_PROVIDER` | `groq` | `groq`, `openai`, `bedrock`, or `openrouter` |
+| `MAX_STEPS` | `30` | Maximum actions before stopping |
+| `STEP_DELAY` | `2` | Seconds between actions (lets UI settle) |
+| `STUCK_THRESHOLD` | `3` | Unchanged screens before recovery kicks in |
+| `VISION_ENABLED` | `true` | Screenshot fallback when accessibility tree is empty |
+
+### LLM Providers
+
+| Provider | Key Variable | Default Model |
+|---|---|---|
+| Groq (free tier) | `GROQ_API_KEY` | `llama-3.3-70b-versatile` |
+| OpenAI | `OPENAI_API_KEY` | `gpt-4o` |
+| AWS Bedrock | AWS credential chain | `us.meta.llama3-3-70b-instruct-v1:0` |
+| OpenRouter | `OPENROUTER_API_KEY` | `anthropic/claude-3.5-sonnet` |
+
+## Available Actions
+
+The agent can perform 15 actions:
+
+| Category | Actions |
+|---|---|
+| Navigation | `tap`, `longpress`, `swipe`, `enter`, `back`, `home` |
+| Text | `type`, `clear` |
+| App Control | `launch` (by package, activity, or URI with extras) |
+| Data | `screenshot`, `clipboard_get`, `clipboard_set` |
+| System | `shell`, `wait`, `done` |
+
+## Project Structure
+
+```
+src/
+  kernel.ts          # Main agent loop (entry point)
+  actions.ts         # ADB action implementations with retry
+  llm-providers.ts   # LLM abstraction (OpenAI, Groq, Bedrock, OpenRouter)
+  sanitizer.ts       # Accessibility XML parser
+  config.ts          # Environment config loader
+  constants.ts       # ADB keycodes, coordinates, defaults
+```
+
+## Notes
+
+- Swipe coordinates in `constants.ts` are calibrated for 1080px-wide screens. Adjust `SWIPE_COORDS` for different resolutions.
+- The agent automatically detects stuck loops and injects recovery hints after `STUCK_THRESHOLD` steps without screen changes.
+- ADB commands retry with exponential backoff (up to `MAX_RETRIES` attempts).