Vibe coding is the practice of building software by describing requirements to an AI model — such as ChatGPT, Claude, or GitHub Copilot — and accepting the generated code without deep review. The developer directs; the AI types. While it dramatically accelerates development speed, it often produces code with structural, semantic, and security weaknesses that accumulate as technical debt.

What is a VibeCode score?

A VibeCode score is VibeFix's proprietary metric that measures the AI signature density of a codebase on a 0–100% scale. Below 30% is classified as Pure Human, 30–50% as Augmented, 50–75% as Likely AI Generated, and above 75% as Synthetic. The score is calculated by the 24-point Neural DNA analysis engine.

How does VibeFix detect AI-generated code?

VibeFix detects AI-generated code using a four-phase pipeline: high-fidelity headless browser rendering, external asset enrichment, a 24-point Neural DNA analysis checking semantic density, class entropy, utility overload, error handling, content voice, and meta signals, then an AI strategic assessment layer producing the VibeCode score.

What is a good VibeCode score?

For production SaaS products, a VibeCode score below 40% (Augmented or Pure Human) is recommended. Scores above 75% (Synthetic) indicate heavy AI generation without quality controls and represent significant technical debt. VibeFix recommends all production deployments target a VibeCode score below 50%.

PR Guardian is VibeFix's automated GitHub pull request review bot. It runs the 24-point Neural DNA analysis on every incoming PR and posts the VibeCode score in the PR comments within 60 seconds. It can block merges for PRs exceeding a configured AI signature threshold. Available on the VibeFix Pro plan.

How is VibeFix different from SonarQube?

SonarQube detects bugs and code smells using predefined rules. VibeFix measures AI signature density using Neural DNA pattern analysis — detecting structural, semantic, and stylistic patterns that rule-based tools cannot see. VibeFix complements SonarQube: SonarQube for functional correctness, VibeFix for structural authenticity.

What is Neural DNA analysis?

Neural DNA analysis is VibeFix's 24-point forensic engine that detects AI pattern signatures in web code by measuring statistical distributions across class naming, DOM structure, CSS patterns, JavaScript logic, page copy, and meta signals — comparing them against known AI model output profiles to produce a VibeCode score.

How much does VibeFix cost?

VibeFix offers three plans: Hobby at $9/month (25 URL scans), Basic at $15/month (100 URL scans, PDF export), and Pro at $49/month (300 URL scans + 1,500 PR bot scans, PR Guardian, GitHub integration, API access). All plans require sign-up at vibefix.site.

Is vibe coding bad for production?

Vibe coding is not inherently bad, but unvetted vibe-coded code is a production risk. AI models generate code that runs but may lack semantic integrity, accessibility, robust error handling, and maintainability. VibeFix recommends running a Neural DNA analysis scan before every major production deployment.

Can VibeFix scan private GitHub repos?

VibeFix scans live public URLs. For private codebases, use a tunneling tool like ngrok for scanning, or use PR Guardian (Pro plan) which integrates directly with GitHub to analyze pull requests without requiring a public URL.

Is VibeFix useful for open source maintainers?

Yes, VibeFix is highly beneficial for open source maintainers and repository owners. The PR Guardian bot automatically reviews pull requests globally, identifying AI-generated code patterns and technical debt before it gets merged. This significantly reduces the manual review burden for open-source project maintainers worldwide.

Why do AI models hallucinate code?

AI models predict the next most likely token based on their training data. If an API has recently changed or the model is asked to solve a highly specific niche problem, it may string together plausible-sounding function names that do not actually exist in the target library.

How do you detect hallucinated code automatically?

Hallucinated code can be detected using automated PR review tools like VibeFix. By performing Neural DNA analysis and integrating with the repository context, VibeFix identifies 'Hallucinated APIs' as a critical AI Code Smell before the code is merged.

AI Failure Mode

What Is Hallucinated Code?

By VibeFix Engineering Research Team·Published May 2026·4 min read

Hallucinated code refers to output from AI language models that includes functionally invalid syntax, non-existent software packages, or fabricated API endpoints. The code often appears highly convincing and syntactically flawless to human reviewers but completely fails at runtime.

TL;DR

What it is: Fake code generated by AI that looks real.
The Risk: Human reviewers frequently approve it because it looks correct at a glance, leading to severe runtime crashes.
The Solution: Deploy AI code detectors and strict PR review automation to identify unverified API calls.

Examples of Code Hallucinations

A common example is an AI model attempting to use a third-party payment processing library. It might invent a function called Stripe.processPaymentFast() because it statistically matches surrounding context, even though no such method exists in the actual Stripe SDK.

Another severe variation is "Context Amnesia," where the AI hallucinates variables or state components that were declared in a different file but never actually imported or passed down in the current scope.

Related Terms

AI Code SmellContext AmnesiaDetect AI Generated CodeAgentic Code Review

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