Is this AI‑generated?

Cobalynx answers with evidence: paste text for a calibrated probability with published error rates — never a guess — or check a file's provenance credentials. No signup, no interstitials.

0 words · 0 characters · 150 to 10,000 words

What our verdicts mean

Measured in one sanctioned run on a frozen held-out evaluation set — clean, non-native and adversarial slices together, so paraphrase-attacked and older AI text weighs on these rates (August 16, 2026; every run of the measurement is disclosed in the ledger), abstentions included:

  • When we say likely AI, the text was actually human 0.7% of the time (3 of 442; statistical upper bound 2.0%).
  • When we say likely human, the text was actually AI 26.9% of the time (223 of 829; statistical upper bound 30.0%).
  • We answer inconclusive — and say so, instead of guessing — on 16.5% of that evaluation set (251 of 1522).

Measured accuracy, published

We evaluated the detector in one sanctioned run on a frozen held-out set and committed the results — error rates with confidence intervals, not a marketing number. Every figure on this site traces back to that measurement, and every execution of the measurement command is disclosed in an append-only run ledger.

See the evidence

Watermark-aware, honest about limits

Some providers watermark their text; most do not. We track who actually does — and we will never claim to detect a watermark that was never embedded. Nobody can.

How watermarks work

Built against false accusations

A wrong “AI” verdict can cost a student or writer dearly. That is why we refuse texts too short to judge, show a calibrated probability instead of a confident label, and abstain when the evidence is thin. Already been flagged by another tool? Start here.

Our false-positive protections

How a scan works

  1. Score. Multiple independent signal families — statistical and learned — score your text as a whole and section by section; the per-section scores are what the heatmap bands show.
  2. Calibrate. Raw scores are calibrated against measured outcomes, so the probability you see means what it says.
  3. Report — or abstain. Clear cases get a verdict with a probability; borderline cases are reported as inconclusive, not guessed.
Read the full methodology

Watermark adapter status

Provider states as reviewed on August 16, 2026 (served live by the detection service):

  • Google announced SynthID-Text published by Google DeepMind (Nature 2024, open-sourced detector code), and deployed in Gemini — but no public verification API is available for third parties, so no adapter can go live.
  • Anthropic announced Anthropic announced (Aug 11-14, 2026) that Claude models launched after Aug 2, 2026 watermark their text output; its detection API is announced but not yet public, so no adapter can go live.
  • OpenAI unavailable OpenAI built a text watermarking method internally (reported 2024) but has not released it or any verification API; pending.
  • Meta unavailable Meta published watermarking research (e.g. video/audio; Three Bricks for text) but ships no public text watermark verification; pending.
  • Mistral unavailable No announced text watermarking or verification API from Mistral; pending.
  • Microsoft unavailable Microsoft backs C2PA for media provenance but exposes no text watermark verification API; pending.
  • xAI unavailable No announced text watermarking from xAI.