cyborg-hunter

Detects AI-tool use during browser-based behavioral experiments. Captures paste, copy, drag, tab-away, mouse trajectories, browser sidebar openings, and other signals that compromise data quality on Prolific / MTurk / classroom studies. Produces a triage report ranking participants by suspiciousness.

Optional companion deterrence modules (extension-guard-friction.js, extension-guard-honeypot.js) ship in the same package: friction enforces fullscreen + blocks sidebars + scrambles content during violations + asks cooperative LLMs to refuse; honeypot exposes both hidden and visible bait fields that AI agents fill while human participants don't see them.

Example: 100-participant Prolific pilot

| Rank | Participant | Score | Hard | Reason | |------|-------------|-------|------|--------| | 1 | 67c1d6d98c8787be36609212 | 4078 | no | 1 tab-away 3–10s; 2 flickers <3s; fast typing on 9 trials; 1015 synthetic insertions | | 2 | 69bc21dd22f17b2337957511 | 179 | YES | 21 paste events; 3 copy events; 9 tab-aways ≥10s; 3 sidebar events; 21 layout shifts | | 3 | 69b9f3184e0896ef41b99aa8 | 152 | no | 38 synthetic insertions | | 4 | 5d350282cec7150015d16494 | 131 | YES | 5 paste events; 10 copy events; 22 tab-aways ≥10s; 5 tab-aways 3–10s; 15 flickers <3s |

6 hard-flagged + 12 soft-flagged out of 100. Per-participant tab-away timeline (rank 4, 42 events across 15 trials):

Repo layout

• src/core/ — signal-collection library (the monitor)
• src/jspsych/ — jsPsych extension adapters (one per concern)
• src/cli/ + bin/ — CLI that turns saved data into the triage report
• tests/, docs/, studies/ — tests, package docs, full-study fixtures

Install

CLI (analysis):

npm install -g cyborg-hunter

Browser (experiment page) — load via unpkg or copy dist/*.js into your project:

<!-- Signal collection -->
<script src="https://unpkg.com/cyborg-hunter/dist/cyborg-hunter.min.js"></script>
<script src="https://unpkg.com/cyborg-hunter/dist/extension-cyborg-hunter.js"></script>
<!-- Optional: deterrence + bait detection -->
<script src="https://unpkg.com/cyborg-hunter/dist/extension-guard-friction.js"></script>
<script src="https://unpkg.com/cyborg-hunter/dist/extension-guard-honeypot.js"></script>

For production studies, pin a version: https://unpkg.com/[email protected]/dist/....

Plug into a jsPsych experiment

const jsPsych = initJsPsych({
  extensions: [
    { type: jsPsychCyborgHunter, params: { participantId: participant_id, preset: 'standard' } },
    { type: jsPsychGuardFriction },     // optional
    { type: jsPsychGuardHoneypot }      // optional
  ],
  on_finish: function () {
    jsPsych.extensions['guard-friction'].finalize();   // stop friction first
    jsPsych.extensions['guard-honeypot'].finalize();   // then attach data
    jsPsych.extensions['cyborg-hunter'].finalize();    // then save
    jsPsych.data.get().localSave('csv', 'data.csv');
  }
});

timeline.push(jsPsychGuardFriction.entryTrial());     // user-gesture fullscreen entry
timeline.forEach(t => t.extensions = (t.extensions || []).concat([
  { type: jsPsychCyborgHunter },
  { type: jsPsychGuardFriction },
  { type: jsPsychGuardHoneypot }
]));
jsPsych.run(timeline);

participantId must exist before initJsPsych. Full walk-through (per-trial params, standalone non-jsPsych use, opt-in/exclude modes): docs/using-cyborg-hunter.md.

Generate a report

cd <your-data-dir>
cyborg-hunter init                # writes cyborg-hunter.config.json
# edit config: dataDir, filePattern, participantIdField
cyborg-hunter report              # writes ./cyborg-hunter-report/
open cyborg-hunter-report/index.html

Output: summary.csv (per-participant columns), triage.md (ranked list), event-log.csv (chronological events), images/ (per-participant mouse paths, tab timelines, typing profiles), index.html (landing page).

What it detects

| Signal | How | Class | |---|---|---| | Paste | Clipboard paste events | Hard (count threshold) | | Drag-and-drop | drop events on inputs | Hard (count threshold) | | Copy | Clipboard copy events | Soft (weighted) | | Tab-away | visibilitychange + blur/focus | Soft (weighted) | | Browser sidebar | innerWidth delta + layout compression | Soft (weighted) | | Suspicious typing speed | chars/sec exceeding preset threshold | Soft (weighted) | | Synthetic insertion | text appearing without keystrokes | Soft (weighted) | | Foreign input | typing landing outside experiment container | Soft (weighted) | | Idle gaps | input inactivity | Soft (weighted) | | AI-extension content scripts | DOM scan for known extension selectors | Soft (weighted) | | Mouse trajectories | 20Hz polling + path-efficiency metrics | Diagnostic | | Window/screen geometry | polled + resize-event capture, with zoom inference | Diagnostic |

Three presets: permissive / standard (default) / strict. Per-signal thresholds: docs/signals-reference.md.

The optional guard extensions add: fullscreen / sidebar / focus enforcement (with content-scrambling overlay on violation), AI refusal notices in the DOM, and honeypot fields (hidden + visible bait) that catch sidebar-LLMs and agentic browsers (Browser Use, Operator, Computer Use) — captured as ai_use / ai_report columns.

What it doesn't detect

• Native browser AI sidebars (Chrome Gemini, Edge Copilot) — they leave no extension content scripts. The innerWidth_delta heuristic still catches them as generic sidebar events, but the named-extension column stays empty.
• Screen-share / second device — an LLM on a phone reading the screen leaves no in-browser trace.
• AI text edited and retyped — a determined participant who retypes character-by-character without tab-switching looks clean. Mouse-trajectory and typing-rhythm signals raise the bar but it isn't a polygraph.

Documentation

• docs/using-cyborg-hunter.md — full integration guide
• docs/signals-reference.md — every signal with thresholds per preset
• docs/configuration.md — config file fields and CLI flags
• docs/cli-reference.md — commands and output structure
• docs/design-decisions.md — architecture rationale

Citation

@software{konuk2026cyborghunter,
  author  = {Konuk, Can},
  title   = {cyborg-hunter: integrity monitoring for online behavioral experiments},
  year    = {2026},
  url     = {https://github.com/konukcan/cyborg-hunter},
  version = {0.4.0}
}

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License

MIT