Files
droidclaw/src/kernel.ts
Sanju Sivalingam 6a63af1a68 Add ASCII art banner to CLI and update gitignore
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
2026-02-16 20:00:46 +05:30

556 lines
21 KiB
TypeScript

/**
* DroidClaw - Main Agent Loop (TypeScript/Bun Edition)
*
* An AI agent that controls Android devices through the accessibility API.
* Uses LLMs to make decisions based on screen context.
*
* Features:
* - Perception -> Reasoning -> Action loop
* - Screen state diffing (stuck loop detection)
* - Error recovery with retries
* - Vision fallback & always-on multimodal screenshots
* - Dynamic early exit on goal completion
* - Smart element filtering (compact JSON, top-N scoring)
* - Multi-turn conversation memory
* - Multi-step planning (think/plan/planProgress)
* - Streaming LLM responses
* - Session logging with crash-safe partial writes
* - Auto-detect screen resolution & foreground app
* - 15 actions: tap, type, enter, swipe, home, back, wait, done,
* longpress, screenshot, launch, clear, clipboard_get, clipboard_set, shell
*
* Usage:
* bun run src/kernel.ts
*/
import { existsSync, readFileSync } from "fs";
import { Config } from "./config.js";
import {
executeAction,
runAdbCommand,
getScreenResolution,
getForegroundApp,
initDeviceContext,
sanitizeCoordinates,
type ActionDecision,
type ActionResult,
} from "./actions.js";
import { executeSkill } from "./skills.js";
import {
getLlmProvider,
trimMessages,
parseJsonResponse,
SYSTEM_PROMPT,
type LLMProvider,
type ChatMessage,
type ContentPart,
} from "./llm-providers.js";
import {
getInteractiveElements,
computeScreenHash,
filterElements,
type UIElement,
} from "./sanitizer.js";
import {
DEVICE_SCREENSHOT_PATH,
LOCAL_SCREENSHOT_PATH,
} from "./constants.js";
import { SessionLogger } from "./logger.js";
// ===========================================
// Screen Perception
// ===========================================
interface ScreenState {
elements: UIElement[];
compactJson: string;
}
/**
* Dumps the current UI XML and returns parsed elements + compact filtered JSON for the LLM.
*/
function getScreenState(): ScreenState {
try {
runAdbCommand(["shell", "uiautomator", "dump", Config.SCREEN_DUMP_PATH]);
runAdbCommand(["pull", Config.SCREEN_DUMP_PATH, Config.LOCAL_DUMP_PATH]);
} catch {
console.log("Warning: ADB screen capture failed.");
return { elements: [], compactJson: "Error: Could not capture screen." };
}
if (!existsSync(Config.LOCAL_DUMP_PATH)) {
return { elements: [], compactJson: "Error: Could not capture screen." };
}
const xmlContent = readFileSync(Config.LOCAL_DUMP_PATH, "utf-8");
const elements = getInteractiveElements(xmlContent);
const compact = filterElements(elements, Config.MAX_ELEMENTS);
return { elements, compactJson: JSON.stringify(compact) };
}
/**
* Captures a screenshot and returns the base64-encoded PNG, or null on failure.
*/
function captureScreenshotBase64(): string | null {
try {
runAdbCommand(["shell", "screencap", "-p", DEVICE_SCREENSHOT_PATH]);
runAdbCommand(["pull", DEVICE_SCREENSHOT_PATH, LOCAL_SCREENSHOT_PATH]);
if (existsSync(LOCAL_SCREENSHOT_PATH)) {
const buffer = readFileSync(LOCAL_SCREENSHOT_PATH);
return Buffer.from(buffer).toString("base64");
}
} catch {
console.log("Warning: Screenshot capture failed.");
}
return null;
}
// ===========================================
// Screen State Diffing
// ===========================================
interface ScreenDiff {
changed: boolean;
addedTexts: string[];
removedTexts: string[];
summary: string;
}
function diffScreenState(
prevElements: UIElement[],
currElements: UIElement[]
): ScreenDiff {
const prevTexts = new Set(prevElements.map((e) => e.text).filter(Boolean));
const currTexts = new Set(currElements.map((e) => e.text).filter(Boolean));
const addedTexts = [...currTexts].filter((t) => !prevTexts.has(t));
const removedTexts = [...prevTexts].filter((t) => !currTexts.has(t));
const prevHash = computeScreenHash(prevElements);
const currHash = computeScreenHash(currElements);
const changed = prevHash !== currHash;
let summary = "";
if (!changed) {
summary = "Screen has NOT changed since last action.";
} else {
const parts: string[] = [];
if (addedTexts.length > 0) {
parts.push(`New on screen: ${addedTexts.slice(0, 5).join(", ")}`);
}
if (removedTexts.length > 0) {
parts.push(`Gone from screen: ${removedTexts.slice(0, 5).join(", ")}`);
}
summary = parts.join(". ") || "Screen layout changed.";
}
return { changed, addedTexts, removedTexts, summary };
}
// ===========================================
// Streaming LLM Consumer
// ===========================================
async function getDecisionStreaming(
llm: LLMProvider,
messages: ChatMessage[]
): Promise<ActionDecision> {
if (!Config.STREAMING_ENABLED || !llm.capabilities.supportsStreaming || !llm.getDecisionStream) {
return llm.getDecision(messages);
}
let accumulated = "";
process.stdout.write("Thinking");
for await (const chunk of llm.getDecisionStream(messages)) {
accumulated += chunk;
process.stdout.write(".");
}
process.stdout.write("\n");
return parseJsonResponse(accumulated);
}
// ===========================================
// Main Agent Loop
// ===========================================
export async function runAgent(goal: string, maxSteps?: number): Promise<{ success: boolean; stepsUsed: number }> {
const steps = maxSteps ?? Config.MAX_STEPS;
// Phase 1A: Auto-detect screen resolution
const resolution = getScreenResolution();
if (resolution) {
initDeviceContext(resolution);
console.log(`Screen resolution: ${resolution[0]}x${resolution[1]}`);
} else {
console.log("Screen resolution: using default 1080x2400 swipe coords");
}
console.log("DroidClaw Started");
console.log(`Goal: ${goal}`);
console.log(`Provider: ${Config.LLM_PROVIDER} (${Config.getModel()})`);
console.log(`Max steps: ${steps} | Step delay: ${Config.STEP_DELAY}s`);
console.log(`Vision: ${Config.VISION_MODE} | Streaming: ${Config.STREAMING_ENABLED}`);
console.log(`Max elements: ${Config.MAX_ELEMENTS} | History: ${Config.MAX_HISTORY_STEPS} steps`);
const llm = getLlmProvider();
// Phase 2B: Session logging
const logger = new SessionLogger(
Config.LOG_DIR,
goal,
Config.LLM_PROVIDER,
Config.getModel()
);
// Phase 4A: Multi-turn conversation memory
const messages: ChatMessage[] = [
{ role: "system", content: SYSTEM_PROMPT },
];
let prevElements: UIElement[] = [];
let stuckCount = 0;
let recentActions: string[] = []; // Sliding window of action signatures for repetition detection
let lastActionFeedback = ""; // Result of previous action to feed back to LLM
for (let step = 0; step < steps; step++) {
console.log(`\n--- Step ${step + 1}/${steps} ---`);
// 1. Perception: Capture screen state
console.log("Scanning screen...");
const { elements, compactJson: screenContext } = getScreenState();
// 1B. Foreground app detection
const foregroundApp = getForegroundApp();
if (foregroundApp) {
console.log(`Foreground: ${foregroundApp}`);
}
// 2. Screen diff: detect stuck loops
let diffContext = "";
let screenChanged = true;
if (step > 0) {
const diff = diffScreenState(prevElements, elements);
screenChanged = diff.changed;
diffContext = `\n\nSCREEN_CHANGE: ${diff.summary}`;
if (!diff.changed) {
stuckCount++;
console.log(
`Warning: Screen unchanged for ${stuckCount} step(s).`
);
if (stuckCount >= Config.STUCK_THRESHOLD) {
console.log(
`Stuck for ${stuckCount} steps. Injecting recovery hint.`
);
// Context-aware recovery hints based on what actions are failing
const failingTypes = new Set(
recentActions.slice(-stuckCount).map((a) => a.split("(")[0])
);
let hint = `\nWARNING: You have been stuck for ${stuckCount} steps. The screen is NOT changing.`;
if (failingTypes.has("tap") || failingTypes.has("longpress")) {
hint +=
`\nYour tap/press actions are having NO EFFECT. Likely causes:` +
`\n- The action SUCCEEDED SILENTLY (copy/share/like buttons often work without screen changes). If so, MOVE ON to the next step.` +
`\n- The element is not actually interactive at those coordinates.` +
`\n- USE "clipboard_set" to set clipboard text directly instead of UI copy buttons.` +
`\n- Or just "type" the text directly in the target app — you already have the text from SCREEN_CONTEXT.`;
}
if (failingTypes.has("swipe") || failingTypes.has("scroll")) {
hint +=
`\nSwiping is having no effect — you may be at the end of scrollable content. Try interacting with visible elements or navigate with "back"/"home".`;
}
hint +=
`\nYour plan is NOT working. You MUST create a completely NEW plan with a different approach. Think about the underlying GOAL, not the specific steps that failed.`;
diffContext += hint;
}
} else {
stuckCount = 0;
}
}
prevElements = elements;
// 2B. Repetition detection (persists across screen changes — catches retry loops)
if (recentActions.length >= 3) {
const freq = new Map<string, number>();
for (const a of recentActions) freq.set(a, (freq.get(a) ?? 0) + 1);
const [topAction, topCount] = [...freq.entries()].reduce(
(a, b) => (b[1] > a[1] ? b : a),
["", 0]
);
if (topCount >= 3) {
diffContext +=
`\nREPETITION_ALERT: You have attempted "${topAction}" ${topCount} times in recent steps. ` +
`This action is clearly NOT working — do NOT attempt it again.`;
if (topAction.includes("tap") || topAction.includes("longpress")) {
diffContext +=
` ALTERNATIVES: (1) If you were copying text, the copy likely already succeeded — move on to the next step. ` +
`(2) Use "clipboard_set" with the text from SCREEN_CONTEXT to set clipboard directly. ` +
`(3) Use "type" to enter text directly in the target app. ` +
`(4) Navigate away with "back" or "home" and try a different path.`;
}
}
}
// 2C. Drift detection — agent is floundering (swipe/back/wait/screenshot spam)
if (recentActions.length >= 4) {
const navigationActions = new Set(["swipe", "scroll", "back", "home", "wait"]);
const navCount = recentActions
.slice(-5)
.filter((a) => navigationActions.has(a.split("(")[0])).length;
if (navCount >= 4) {
diffContext +=
`\nDRIFT_WARNING: Your last ${navCount} actions were all navigation/waiting (swipe, back, wait, screenshot) with no direct interaction. ` +
`You are not making progress. STOP scrolling/navigating and take a DIRECT action: ` +
`tap a specific button from SCREEN_CONTEXT, use "type" to enter text, or use "clipboard_set". ` +
`If you need to submit a query in a chat app, find the Send button in SCREEN_CONTEXT and tap it.`;
}
}
// 3. Vision: capture screenshot based on VISION_MODE or stuck recovery
let screenshotBase64: string | null = null;
let visionContext = "";
const isStuckVision = stuckCount >= 2; // Send screenshot after 2 unchanged steps
const shouldCaptureVision =
Config.VISION_MODE === "always" ||
(Config.VISION_MODE === "fallback" && elements.length === 0) ||
isStuckVision;
if (shouldCaptureVision) {
screenshotBase64 = captureScreenshotBase64();
if (elements.length === 0) {
visionContext =
"\n\nVISION_FALLBACK: The accessibility tree returned NO elements. " +
"A screenshot has been captured. The screen likely contains custom-drawn " +
"content (game, WebView, or Flutter). Try using coordinate-based taps on " +
"common UI positions, or use 'back'/'home' to navigate away.";
} else if (isStuckVision) {
visionContext =
"\n\nVISION_ASSIST: You have been stuck — a screenshot is attached. " +
"Use the screenshot to VISUALLY identify the correct field positions, " +
"buttons, and layout. The accessibility tree may be misleading about " +
"which field is which. Trust what you SEE in the screenshot over the " +
"element coordinates when they conflict.";
}
if (screenshotBase64 && llm.capabilities.supportsImages) {
console.log(isStuckVision ? "Stuck — sending screenshot for visual assist" : "Sending screenshot to LLM");
}
}
// 4. Build user message with all context
const foregroundLine = foregroundApp
? `FOREGROUND_APP: ${foregroundApp}\n\n`
: "";
const actionFeedbackLine = lastActionFeedback
? `LAST_ACTION_RESULT: ${lastActionFeedback}\n\n`
: "";
const textContent =
`GOAL: ${goal}\n\n${foregroundLine}${actionFeedbackLine}SCREEN_CONTEXT:\n${screenContext}${diffContext}${visionContext}`;
// Build content parts (text + optional image)
const userContent: ContentPart[] = [{ type: "text", text: textContent }];
if (screenshotBase64 && llm.capabilities.supportsImages) {
userContent.push({
type: "image",
base64: screenshotBase64,
mimeType: "image/png",
});
}
messages.push({ role: "user", content: userContent });
// Trim messages to keep within history limit
const trimmed = trimMessages(messages, Config.MAX_HISTORY_STEPS);
// 5. Reasoning: Get LLM decision
const llmStart = performance.now();
let decision: ActionDecision;
try {
decision = await getDecisionStreaming(llm, trimmed);
} catch (err) {
console.log(`LLM Error: ${(err as Error).message}`);
console.log("Falling back to wait action.");
decision = { action: "wait", reason: "LLM request failed, waiting" };
}
const llmLatency = performance.now() - llmStart;
// Log thinking and planning
if (decision.think) {
console.log(`Think: ${decision.think}`);
}
if (decision.plan) {
console.log(`Plan: ${decision.plan.join(" -> ")}`);
}
if (decision.planProgress) {
console.log(`Progress: ${decision.planProgress}`);
}
console.log(`Decision: ${decision.action}${decision.reason ?? "no reason"} (${Math.round(llmLatency)}ms)`);
// Append assistant response to conversation
messages.push({
role: "assistant",
content: JSON.stringify(decision),
});
// 6. Action: Execute the decision (multi-step actions or basic actions)
const MULTI_STEP_ACTIONS = ["read_screen", "submit_message", "copy_visible_text", "wait_for_content", "find_and_tap", "compose_email"];
const actionStart = performance.now();
let result: ActionResult;
try {
if (MULTI_STEP_ACTIONS.includes(decision.action)) {
result = executeSkill(decision, elements);
} else {
result = executeAction(decision);
}
} catch (err) {
console.log(`Action Error: ${(err as Error).message}`);
result = { success: false, message: (err as Error).message };
}
const actionLatency = performance.now() - actionStart;
// Log step
logger.logStep(
step + 1,
foregroundApp,
elements.length,
screenChanged,
decision,
result,
Math.round(llmLatency),
Math.round(actionLatency)
);
// Track action signature for repetition detection
const actionSig = decision.coordinates
? `${decision.action}(${decision.coordinates.join(",")})`
: decision.action;
recentActions.push(actionSig);
if (recentActions.length > 8) recentActions.shift();
// Capture action result feedback for next iteration
lastActionFeedback = `${actionSig}${result.success ? "OK" : "FAILED"}: ${result.message}`;
console.log(`Messages in context: ${trimmed.length}`);
// 7. Check for goal completion
if (decision.action === "done") {
console.log("\nTask completed successfully.");
logger.finalize(true);
return { success: true, stepsUsed: step + 1 };
}
// Wait for UI to update
await Bun.sleep(Config.STEP_DELAY * 1000);
}
console.log("\nMax steps reached. Task may be incomplete.");
logger.finalize(false);
return { success: false, stepsUsed: steps };
}
// ===========================================
// Entry Point
// ===========================================
const BANNER = `
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`;
async function main(): Promise<void> {
console.log(BANNER);
try {
Config.validate();
} catch (e) {
console.log(`Configuration Error: ${(e as Error).message}`);
return;
}
// Check for --flow flag (deterministic YAML flows, no LLM)
const flowIdx = process.argv.findIndex((a) => a === "--flow" || a.startsWith("--flow="));
if (flowIdx !== -1) {
const flowArg = process.argv[flowIdx];
const flowFile = flowArg.includes("=")
? flowArg.split("=")[1]
: process.argv[flowIdx + 1];
if (!flowFile) {
console.log("Error: --flow requires a YAML file path.");
process.exit(1);
}
const { runFlow } = await import("./flow.js");
try {
const result = await runFlow(flowFile);
console.log(`\nResult: ${result.success ? "OK" : "FAILED"} (${result.stepsCompleted}/${result.totalSteps} steps)`);
process.exit(result.success ? 0 : 1);
} catch (e) {
console.log(`Flow Error: ${(e as Error).message}`);
process.exit(1);
}
}
// Check for --workflow flag
const workflowIdx = process.argv.findIndex((a) => a === "--workflow" || a.startsWith("--workflow="));
if (workflowIdx !== -1) {
const arg = process.argv[workflowIdx];
const workflowFile = arg.includes("=")
? arg.split("=")[1]
: process.argv[workflowIdx + 1];
if (!workflowFile) {
console.log("Error: --workflow requires a JSON file path.");
process.exit(1);
}
const { runWorkflow } = await import("./workflow.js");
const workflow = JSON.parse(await Bun.file(workflowFile).text());
const result = await runWorkflow(workflow);
console.log(`\n=== Workflow "${result.name}" ===`);
for (const step of result.steps) {
const status = step.success ? "OK" : "FAILED";
console.log(` [${status}] ${step.goal} (${step.stepsUsed} steps)${step.error ? `${step.error}` : ""}`);
}
console.log(`\nResult: ${result.success ? "All steps completed" : "Some steps failed"}`);
process.exit(result.success ? 0 : 1);
}
// Interactive mode: read goal from stdin
process.stdout.write("Enter your goal: ");
const goal = await new Promise<string>((resolve) => {
const reader = Bun.stdin.stream().getReader();
reader.read().then(({ value }) => {
resolve(new TextDecoder().decode(value).trim());
reader.releaseLock();
});
});
if (!goal) {
console.log("No goal provided. Exiting.");
return;
}
await runAgent(goal);
}
main();