browser-use-js: preserve complete final output

javascript/src/cli.ts

@@ -2,6 +2,7 @@
 
 import { readFile } from "node:fs/promises";
 import { Agent } from "./agent.js";
+import { eventJsonLine, resultJsonLine } from "./event-json.js";
 
 const args = process.argv.slice(2);
 const taskFileIndex = args.indexOf("--task-file");
@@ -23,11 +24,11 @@ try {
     reasoningEffort: reasoningEffort(process.env.BROWSER_USE_JS_REASONING_EFFORT),
     maxSteps: integer(process.env.BROWSER_USE_JS_MAX_STEPS, 100),
     onEvent: (event) => {
-      process.stdout.write(`${JSON.stringify(sanitize(event))}\n`);
+      process.stdout.write(eventJsonLine(event));
     },
   }).run();
   const { messages: _messages, ...summary } = result;
-  process.stdout.write(`${JSON.stringify({ type: "browser_use_js_result", result: sanitize(summary) })}\n`);
+  process.stdout.write(resultJsonLine(summary));
 } catch (error) {
   const message = error instanceof Error ? `${error.name}: ${error.message}` : String(error);
   process.stdout.write(`${JSON.stringify({ type: "browser_use_js_error", error: message })}\n`);
@@ -35,22 +36,6 @@ try {
   process.exitCode = 1;
 }
 
-function sanitize(value: unknown): unknown {
-  if (Array.isArray(value)) return value.map(sanitize);
-  if (!value || typeof value !== "object") {
-    return typeof value === "string" && value.length > 30_000
-      ? `${value.slice(0, 30_000)}... <${value.length - 30_000} chars omitted>`
-      : value;
-  }
-  const result: Record<string, unknown> = {};
-  for (const [key, item] of Object.entries(value as Record<string, unknown>)) {
-    result[key] = key === "data" && typeof item === "string" && item.length > 10_000
-      ? `<image:${item.length} chars>`
-      : sanitize(item);
-  }
-  return result;
-}
-
 function integer(value: string | undefined, fallback: number): number {
   const parsed = Number.parseInt(value ?? "", 10);
   return Number.isFinite(parsed) && parsed > 0 ? parsed : fallback;

javascript/src/event-json.ts

@@ -0,0 +1,27 @@
+const MAX_EVENT_STRING_CHARS = 30_000;
+
+/** Encode a bounded Pi event for JSONL logs and telemetry ingestion. */
+export function eventJsonLine(event: unknown): string {
+  return `${JSON.stringify(sanitizeEvent(event))}\n`;
+}
+
+/** Encode the public result without clipping the user's final deliverable. */
+export function resultJsonLine(result: unknown): string {
+  return `${JSON.stringify({ type: "browser_use_js_result", result })}\n`;
+}
+
+function sanitizeEvent(value: unknown): unknown {
+  if (Array.isArray(value)) return value.map(sanitizeEvent);
+  if (!value || typeof value !== "object") {
+    return typeof value === "string" && value.length > MAX_EVENT_STRING_CHARS
+      ? `${value.slice(0, MAX_EVENT_STRING_CHARS)}... <${value.length - MAX_EVENT_STRING_CHARS} chars omitted>`
+      : value;
+  }
+  const result: Record<string, unknown> = {};
+  for (const [key, item] of Object.entries(value as Record<string, unknown>)) {
+    result[key] = key === "data" && typeof item === "string" && item.length > 10_000
+      ? `<image:${item.length} chars>`
+      : sanitizeEvent(item);
+  }
+  return result;
+}

javascript/test/cdp.test.mjs

@@ -2,6 +2,15 @@ import assert from "node:assert/strict";
 import test from "node:test";
 import { WebSocketServer } from "ws";
 import { CdpSession, createBrowserSession } from "../dist/cdp.js";
+import { eventJsonLine, resultJsonLine } from "../dist/event-json.js";
+
+test("CLI clips trace events without clipping the final deliverable", () => {
+  const output = "x".repeat(40_000);
+  const event = JSON.parse(eventJsonLine({ output }));
+  const result = JSON.parse(resultJsonLine({ output }));
+  assert.match(event.output, /chars omitted/);
+  assert.equal(result.result.output, output);
+});
 
 test("CDP session attaches once and routes page calls through the active session", async () => {
   const requests = [];