Automatic Detection of LLM-Generated Code: A Comparative Case Study of Contemporary Models Across Function and Class Granularities

Fuente: arXiv
Gespeichert in:
Bibliographische Detailangaben
Hauptverfasser: Rahman, Musfiqur, Khatoonabadi, SayedHassan, Abdellatif, Ahmad, Shihab, Emad
Format: Preprint
Veröffentlicht: 2024
Schlagworte:
Online-Zugang:
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
_version_ 1866912780937854976
author Rahman, Musfiqur
Khatoonabadi, SayedHassan
Abdellatif, Ahmad
Shihab, Emad
author_facet Rahman, Musfiqur
Khatoonabadi, SayedHassan
Abdellatif, Ahmad
Shihab, Emad
contents The adoption of Large Language Models (LLMs) for code generation risks incorporating vulnerable code into software systems. Existing detectors face two critical limitations: a lack of systematic cross-model validation and opaque "black box" operation. We address this through a comparative study of code generated by four distinct LLMs: GPT-3.5, Claude 3 Haiku, Claude Haiku 4.5, and GPT-OSS. Analyzing 14,485 Python functions and 11,913 classes from the CodeSearchNet dataset, we generated corresponding code with all four LLMs. Using interpretable software metrics, we trained CatBoost classifiers for each configuration. Our analysis reveals that granularity effects dominate model differences by a factor of 8.6, with negligible feature overlap, indicating that function-level and class-level detection rely on fundamentally disjoint structural signatures. We discover critical granularity-dependent inversions: while modern models (Claude, GPT-OSS) are more detectable at the class level, GPT-3.5 is an anomaly that uniquely excels at the function level. SHAP analysis identifies the Comment-to-Code Ratio as the sole universal discriminator. However, its predictive magnitude varies drastically across models, explaining why detectors trained on specific LLMs fail to generalize. Our findings demonstrate that GPT-3.5's exceptional detectability (AUC-ROC 0.96) is unrepresentative of contemporary models (AUC-ROC approximately between 0.68 and 0.80). Robust detection requires moving beyond single-model studies to account for substantial diversity in structural fingerprints across architectures and granularities.
format Preprint
id arxiv_https___arxiv_org_abs_2409_01382
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Automatic Detection of LLM-Generated Code: A Comparative Case Study of Contemporary Models Across Function and Class Granularities
Rahman, Musfiqur
Khatoonabadi, SayedHassan
Abdellatif, Ahmad
Shihab, Emad
Software Engineering
Artificial Intelligence
Machine Learning
The adoption of Large Language Models (LLMs) for code generation risks incorporating vulnerable code into software systems. Existing detectors face two critical limitations: a lack of systematic cross-model validation and opaque "black box" operation. We address this through a comparative study of code generated by four distinct LLMs: GPT-3.5, Claude 3 Haiku, Claude Haiku 4.5, and GPT-OSS. Analyzing 14,485 Python functions and 11,913 classes from the CodeSearchNet dataset, we generated corresponding code with all four LLMs. Using interpretable software metrics, we trained CatBoost classifiers for each configuration. Our analysis reveals that granularity effects dominate model differences by a factor of 8.6, with negligible feature overlap, indicating that function-level and class-level detection rely on fundamentally disjoint structural signatures. We discover critical granularity-dependent inversions: while modern models (Claude, GPT-OSS) are more detectable at the class level, GPT-3.5 is an anomaly that uniquely excels at the function level. SHAP analysis identifies the Comment-to-Code Ratio as the sole universal discriminator. However, its predictive magnitude varies drastically across models, explaining why detectors trained on specific LLMs fail to generalize. Our findings demonstrate that GPT-3.5's exceptional detectability (AUC-ROC 0.96) is unrepresentative of contemporary models (AUC-ROC approximately between 0.68 and 0.80). Robust detection requires moving beyond single-model studies to account for substantial diversity in structural fingerprints across architectures and granularities.
title Automatic Detection of LLM-Generated Code: A Comparative Case Study of Contemporary Models Across Function and Class Granularities
topic Software Engineering
Artificial Intelligence
Machine Learning
url https://arxiv.org/abs/2409.01382