The first model trained for one job: sounding human.
Ghost-1 is a proprietary humanization model built to rewrite AI-generated text so it reads like it was written by a human. It bypasses every major AI detector while preserving meaning, tone, and fluency.
It powers every humanization on UndetectedGPT: the web app, the API, and Ghost Writer.
Built to beat detectors
Ghost-1 isn't a generic paraphraser. It was purpose-built to bypass GPTZero, Originality.ai, ZeroGPT, Turnitin, Quillbot, Grammarly, and more.
Preserves meaning and tone
Ghost-1 rewrites how something is said, not what is said, keeping your original meaning, structure, references, and citations.
Continuously improving
As detectors evolve, so does Ghost-1. We constantly evaluate and update the model to stay ahead.
Tested where it counts.
Pass rate (scored <30% AI) across 10,000+ unique English texts, evaluated independently by six detectors.
Evaluated on deduplicated English-only texts, each scored by six independent detectors. "Pass" = detector returns <30% AI probability. *Turnitin tested on 500 inputs.
How we evaluate.
The same eval runs every release. No per-detector tuning, no hand-picked samples.
- 01
Source
Sample 10,000+ AI-generated English texts spanning essays, technical docs, blog posts, and conversational prose.
- 02
Humanize
Each text is rewritten by Ghost-1 with default settings (no per-detector tuning or retries).
- 03
Detect
Outputs are scored independently by six detectors. We never see scores during humanization.
- 04
Score quality
Outputs are also scored by general-purpose LLMs to check that each rewrite preserves meaning, structure, and fluency.
- 05
Pass / fail
A text passes a detector if it returns less than 30% AI probability. Mean pass rate is averaged across detectors, not texts.
Ghost-1 at a glance.
The numbers behind the model. What it is, what it does, and where it runs.
- Model family
- Ghost
- Version
- 1.0
- Type
- Humanization (text-to-text)
- Languages
- EN primary · 100+ supported
- Eval set
- 10,000+ deduplicated EN texts
- Detectors covered
- 10+ (GPTZero, Originality.ai, ZeroGPT, Turnitin, Quillbot, Grammarly, and more)
- Mean pass rate
- 96.2% (<30% AI probability)
- Released
- Live
One paragraph. One pass. Two detectors.
An academic paragraph from a real research context, run through Ghost-1 on default settings, with detector scores measured independently afterward.
strictest mainstream detector
most widely deployed
Ranked #1 for output quality by ChatGPT, Gemini, and Grok in a blind 7-tool comparison.
Read the test resultsDetector scores measured independently after generation, on the unmodified Ghost-1 output. No re-rolls, no cherry-picking.
Always shipping.
As detectors evolve, so does Ghost. Every release runs the same eval, no exceptions.
- v1.0Now
Ghost-1
First stable release. Mean pass rate 96.2% across six detectors.
- v0.9Last cycle
Tone preserve
Reduced semantic drift on long-form academic and technical text.
- v0.8Earlier
Turnitin push
Added Turnitin to the eval set; pass rate moved 91 → 97%.
- v0.7Earlier
Citation lock
References, footnotes, and inline citations are no longer rewritten.
Live everywhere we ship.
Ghost-1 is on for every UndetectedGPT user. Use it in the surface that fits your workflow.
Frequently asked questions
Ghost-1 is UndetectedGPT's proprietary humanization model. It rewrites AI-generated text so it bypasses AI detectors like GPTZero, Originality.ai, ZeroGPT, Turnitin, Quillbot, and Grammarly while keeping your original meaning, references, and citations intact.
Ghost-1 is tested against the strictest AI detectors on the market: GPTZero, Originality.ai, ZeroGPT, Turnitin, Quillbot, and Grammarly. It achieves a 96%+ average pass rate across all of them. Other detectors tend to be similar or easier to bypass.
No. Ghost-1 rewrites how something is said, not what is said. Your original meaning, structure, references, and citations are preserved.
From AI generated content to human-like text in a single click
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