Module coherence 

Cross-context stealth coherence probes.

Verifies that the browser’s identity surface (user agent, platform, languages, navigator.webdriver, screen metrics) is coherent across the top-level document, same-origin iframes, and dedicated/shared workers. Drift between contexts is a strong anti-bot detection signal — most anti-bot vendors probe at least one of these auxiliary contexts and compare.

What is a “context”?

The browser exposes three isolation levels that an anti-bot script can probe:

• Top-level document — window of the main frame.
• Same-origin iframe — a <iframe srcdoc=…> injected into the document at probe time. srcdoc iframes inherit the parent’s origin and provide a deterministic, network-free sub-context.
• Dedicated/shared worker — a Worker constructed from a Blob URL. The worker has its own WorkerGlobalScope and its own navigator. Worker probes are best-effort: when the runtime does not expose Worker / Blob / URL.createObjectURL, the worker slot in the report is populated with a ContextObservation::Skipped marker rather than panicking.

Feature flag

This module is default-on and is always compiled as part of the stygian-browser crate. It requires CDP (the stygian-browser default), since the probe runner uses PageHandle::eval to send JavaScript to the page.

Hard failures vs known limitations

Drift is split into two severity bands (see report::DriftSeverity):

• Hard — user_agent, platform, languages, and navigator.webdriver MUST be identical across all observed contexts.
• Known limitation — hardware_concurrency, device_memory, screen metrics, and timezone are documented to differ between Document and Worker contexts in some browser engines.

Idempotence

All probe methods are safely re-runnable. The iframe is removed from the DOM at the end of the probe, the worker is terminate()-ed, and the Blob URL is revokeObjectURL-ed before the probe returns.

Example

use stygian_browser::{BrowserPool, BrowserConfig, WaitUntil};
use stygian_browser::coherence::CoherenceProbe;
use std::time::Duration;

let pool = BrowserPool::new(BrowserConfig::default()).await?;
let handle = pool.acquire().await?;
let mut page = handle
    .browser()
    .expect("valid browser")
    .new_page()
    .await?;
page.navigate(
    "https://example.com",
    WaitUntil::DomContentLoaded,
    Duration::from_secs(30),
)
.await?;

let probe = CoherenceProbe::new();
let report = probe.run(&page).await?;
println!(
    "coherent={} hard_drift={} contexts={}/3",
    report.is_coherent(),
    report.has_hard_drift(),
    report.observed_context_count(),
);

Re-exports

pub use probes::CoherenceProbe;

pub use report::CoherenceDriftReport;

pub use report::ContextKind;

pub use report::ContextObservation;

pub use report::ContextPair;

pub use report::DriftDiagnostic;

pub use report::DriftSeverity;

pub use report::IdentitySurface;

pub use report::build_report;

pub use report::diff_surfaces;

pub use report::field_severity;

pub use report::surface_signature;

Modules

probes

JavaScript probe definitions for cross-context identity surfaces.

report

Cross-context coherence drift report schema.