I benchmarked my browser agent against Browser Use on a live site (150 verified runs, same model). Sending page diffs instead of full re-renders cut token growth by 37%.

Every major browser agent framework fixed the old problem — they all evict old page observations now (I read the source of Browser Use 0.13.6, Skyvern, Stagehand, and Magnitude to confirm). But every one of them still re-sends a full render of the current page on every step — up to 40K chars in Browser Use — even when the only thing that changed is one checkbox. I’ve been building Rote, a memory manager for browser agents, and its core trick is: after one grounded snapshot of a page, send only the diff, keyed by content-derived element IDs (hash of role + name + ancestry) that survive re-renders and navigations. The benchmark: Browser Use 0.13.6 vs Rote, gpt-4.1-mini on both, live WordPress site, five task lengths (9–25 steps), 15 matched runs per cell. Success judged by independent page-state assertions, not the agent’s self-report. Both harnesses went 75/75. Results: • Input growth: 2,160 tokens per step vs 3,437 — 37.2% slower (95% CI 35.6–38.8) • 849 diffs sent, median 24 characters, vs 9,270-char full snapshots (99.6% median reduction) 2.7x fewer output tokens per run Where it loses, because benchmarks without losses are ads: on short tasks (~9 steps) Browser Use is ~15% cheaper in dollars despite using more tokens — their long immutable prefix is exactly what provider caches reward. Cost crosses in my favor around 13 steps, reaching 16% cheaper at 25. Also, eviction means the agent recalls what it did, not what it saw — tasks needing recall of a left page fail by design until I ship a notes mechanism. And Browser Use ships default-on history compaction, which I don’t have yet. Happy to answer anything about the methodology — and if you think the setup is unfair to Browser Use somewhere, tell me and I’ll run it.