The user agent names no headless product
No 'HeadlessChrome' in the user agent and no headless brand in the client hints (severity: critical).
What a detector infers
Both of Chrome's headless modes name themselves in the user agent. New headless (chrome --headless) prefixes the product, so the string reads HeadlessChrome/155.0.0.0; chrome-headless-shell reports HeadlessChrome with the full build number, and also names HeadlessChrome among its client-hint brands. The token appears in navigator.userAgent and in the User-Agent header alike, and a headed browser never carries it.
Measured: Chrome 155 in new headless on Windows and Linux, Edge 155 headless, Playwright's bundled Chromium and chrome-headless-shell all carry it; headed Chrome on a virtual display does not. Until now the audit used the token only together with a Chromium-only brand list, so a default new-headless Chrome — which keeps the normal Chrome brands in its client hints — was never flagged for it.
This row flags the token on its own, at critical severity, because there is nothing to weigh: the browser is describing itself as headless, correctly. It disappears only when the user agent is replaced, with --user-agent or a protocol override, and then the other headless rows have to answer instead.
How to resolve it
Run the browser headed — a virtual display such as Xvfb is enough — if it should present as an ordinary desktop browser. Replacing the user agent removes the word but not the headless behaviour other rows read, and the replacement then has to match the client hints and the TLS handshake as well.
Nearby checks in Automation surface
- No debugger client attached to this tab after it loaded
console-replay-trapV8 keeps the console messages a page logs, which is why DevTools can show messages logged before it was opened. - navigator.webdriver does not assert WebDriver control
webdriver-offThis check is intentionally one-way. The WebDriver specification defines navigator.webdriver as the browser's assertion that it is under… - navigator.webdriver is a native prototype getter returning false
webdriver-descriptor-integrityRather than reading the value, this check inspects the property's shape: it requires a getter on Navigator.prototype whose… - No Selenium / Puppeteer / Playwright globals
automation-globalsThis check tests a fixed list of roughly two dozen known names against both window and document (Selenium's __webdriver_evaluate /… - No anti-detect fingerprint setters left on window
antidetect-fingerprint-settersAnti-detect browsers in the Camoufox family apply a per-context fingerprint through helper functions published on the window object… - DevTools Runtime serialization is not active
runtime-enable-leakAn attached DevTools Runtime domain serialises console arguments and reads an Error stack accessor. - No console preview enumerated a prototype-chain Proxy
console-preview-proxy-trapDevTools has to look inside an object to show it to you, and in JavaScript looking inside an object is an observable act. - No Puppeteer / Playwright sourceURL marker
sourceurl-leakPuppeteer and Playwright evaluation labels can appear in main-world Error stacks.
Clearcote is a browser built for fingerprint coherence
It is a Chromium fork, maintained by the same people who wrote this reference. It ships as a compiled browser rather than as a stealth script injected into someone else's — which is a description of how it is built, and is not an argument about how it behaves on this check.
This audit takes no position on how Clearcote scores on Automation surface checks, on this one, or anywhere else. It has no baseline corpus of other people's fingerprints to rank you against and no vendor scoreboard — nearly every check is self-referential, asking one browser the same question through two independent APIs and reporting whether both answers can be true at once. It runs identically on any browser, including ours. Run it on yours and read the result yourself.
See the other checks in Automation surface — the family headless-ua-token belongs to.