Claude AI Detector
Detect content written by Anthropic's Claude models. Our engine identifies Claude Opus, Sonnet, and Haiku outputs with high precision, analyzing the distinctive writing style of this leading AI assistant.
How Claude Detection Works
Three simple steps to detect Claude-generated content.
Paste Your Text
Paste your text or upload a document. We support PDF, DOCX, and TXT formats for Claude detection.
AI Analyzes for Claude Patterns
Our multi-model detection engine analyzes every sentence for Claude-specific writing patterns and statistical signatures.
Get Sentence-Level Results
Receive a detailed report with per-sentence confidence scores, highlighting exactly which portions are AI-generated.
Why Use a Dedicated Claude Detector?
Anthropic's Claude has rapidly become one of the most popular AI writing assistants, known for its careful, well-structured, and safety-conscious outputs. Plagly.ai's Claude Detector is trained to recognize the specific linguistic fingerprints of Claude models including Opus, Sonnet, and Haiku. Claude tends to produce text with characteristic hedging language, balanced viewpoints, and particular sentence rhythm patterns that differ from GPT-family models. Our detection engine leverages these distinctions through multi-layered analysis, examining vocabulary distributions, rhetorical structures, and token-level probabilities. Whether you need to verify that a piece of content is genuinely human-written or identify Claude's involvement, Plagly gives you clear, sentence-level results you can trust.
Learn more about our technologyAnthropic Claude (Opus, Sonnet & Haiku)
Plagly's detection engine is specifically calibrated for Anthropic Claude (Opus, Sonnet & Haiku), using multi-layer analysis to identify this model's unique writing fingerprint.
Key Features
Everything you need to detect Claude content with confidence.
Claude-Specific Detection
Identifies linguistic patterns unique to Claude models including hedging language, balanced perspectives, and Claude's characteristic writing rhythm.
Sentence-Level Analysis
Every sentence receives an individual AI probability score, making it easy to spot Claude-written passages in mixed documents.
Confidence Scores
Percentage-based confidence lets you assess detection certainty and make informed decisions.
Multi-Format Support
Upload PDFs, DOCX files, or paste text directly. All formats are processed with the same high accuracy.
Privacy Protected
Your content is analyzed in real time without storage. We never retain your documents.
Free to Use
Quick scans are free with no registration. Detect Claude content instantly.
How to Spot Claude Writing
Common tells that a passage was generated by Anthropic Claude (Opus, Sonnet & Haiku):
- Frequent hedging: "it is worth noting," "generally," "in many cases," "I would suggest."
- Careful, balanced framing that weighs multiple perspectives before concluding.
- Clear scaffolding — numbered steps, headers, and neat summaries.
- Warm, measured, slightly formal tone that avoids strong claims.
- Sentences often open with a qualifying clause before the main point.
What Claude-written text actually looks like
Claude's fingerprint is less about vocabulary than posture. Where GPT-family output often reads confident and brisk, Claude tends to qualify, balance and organise. These are the patterns our detector weighs most heavily on this page, and the ones you can check yourself before trusting any score.
Persistent hedging
Phrases like “it’s worth noting”, “that said” and “while X, it’s also true that Y” appear at a much higher rate than in human drafts. Claude is trained to avoid overclaiming, and that caution surfaces as a steady drip of qualifiers throughout a piece.
Unprompted both-sidesing
Asked for an argument, Claude frequently returns a balanced overview instead: the case for, the case against, then a measured synthesis. Human opinion writing usually commits early and spends its length defending that position.
Structure applied by default
Headings, numbered steps and a closing recap show up even on questions that a person would answer in a single paragraph. A short answer arriving with three subheadings is a meaningful signal.
The labelled-bullet pattern
A bolded one- or two-word label, a colon, then an explanation — repeated with unusual parallelism down a list. Human bullets are typically scrappier and less uniform in shape.
Higher burstiness than its peers
This is why Claude can be harder to catch. Most statistical detectors lean on perplexity and burstiness, and Claude varies sentence length more than models that march along at a steady cadence. On this page the structural and hedging signals carry more weight than raw statistics for exactly that reason.
None of these is proof on its own, and careful human writers legitimately share several of them. That is why every result here lists the specific sentences behind the score instead of only a percentage — a number you cannot interrogate is not evidence.
Plagly vs Other Claude Detectors
See how Plagly.ai compares for detecting Claude-generated content.
| Feature | Plagly.ai | GPTZero | Turnitin |
|---|---|---|---|
| Claude Detection | Partial | ||
| Sentence-Level Analysis | Limited | ||
| Free Quick Scans | Limited | — | |
| No Signup Required | — | — | |
| Multi-Model Detection | |||
| Confidence Scores | Limited | ||
| Document Upload | |||
| Privacy (No Storage) | — | — |
Frequently Asked Questions
Common questions about detecting Claude-generated content.
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