Browser fingerprint incoherence, not models, gets web agents blocked

thalissonvs · reddit · 2026-08-22

Web agents are often blocked due to browser fingerprint incoherence rather than model limitations or headless mode. Tests show a plain headless Chrome scores 100 on detection tests (fully flagged as a bot), while a profile matched to the machine drops the score to 15. A mismatched profile (e.g., Windows profile on a Mac) is worse than no injection (score 57) due to conflicting signals. The author maintains pydoll, a Python library that drives Chrome via CDP without webdriver, supports async multi-tab execution, and handles fingerprint injection to prevent blocking.

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