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Rachel Foster

Rachel Foster

Content & Education Lead at Codequiry

Rachel writes Codequiry's practical guides for educators and engineering teams on catching copied and AI-generated code.

Articles by Rachel Foster

A TA's Script for Sorting 300 Code Similarity Reports by Office Hours General 8 min
Rachel Foster Rachel Foster 6 days ago

A TA's Script for Sorting 300 Code Similarity Reports by Office Hours

A teaching assistant at UC San Diego reduced a 312-submission similarity queue to a shortlist of 14 files in about two hours. The workflow relies on Codequiry's outlier scoring, a Python triage script, and a strict two-pass review rule. Here is the exact process, including the script and the thresholds she uses.

Benchmarking MOSS JPlag and Codequiry on 200 Student Submissions General 11 min
Rachel Foster Rachel Foster 1 week ago

Benchmarking MOSS JPlag and Codequiry on 200 Student Submissions

A public university ran MOSS, JPlag, and Codequiry against the same 214 Python submissions, plus 30 AI-generated files. The tools disagreed on nearly a quarter of flagged cases. One combined approach changed how instructors review code.

AI Code Detector False Positives on Boilerplate General 8 min
Rachel Foster Rachel Foster 3 weeks ago

AI Code Detector False Positives on Boilerplate

AI code detectors are producing false positives on the most ordinary submissions in CS1: code that looks the same because the assignment required it. This reported piece examines the data, the workflow changes instructors are making, and why combining AI detection with structural similarity reduces the error rate.

Automating Code Plagiarism Detection in GitHub Actions With Codequiry General 6 min
Rachel Foster Rachel Foster 4 weeks ago

Automating Code Plagiarism Detection in GitHub Actions With Codequiry

Set up an automated code plagiarism detection pipeline in GitHub Actions using Codequiry's REST API. Follow precise steps to write a workflow YAML and a Python script that submits student code, receives similarity scores, flags suspicious pushes, and optionally detects AI-generated code. Includes threshold tuning, result interpretation, and false positive handling.

A Hiring Manager's Audit of AI-Generated Code in Take-Home Tests General 7 min
Rachel Foster Rachel Foster 1 month ago

A Hiring Manager's Audit of AI-Generated Code in Take-Home Tests

An engineering leader audit of 1,284 remote take-home coding submissions found 31.2% flagged as likely AI-generated at high confidence. Manual review confirmed 279 of 401 high-confidence flags, with a 4.5% false positive rate among high-confidence flags. Here is what the data showed and how hiring managers should handle AI detection scores.

How Few AST Nodes Do You Need to Catch a Copied Function General 10 min
Rachel Foster Rachel Foster 1 month ago

How Few AST Nodes Do You Need to Catch a Copied Function

A single function with renamed variables, reordered statements, and changed whitespace can still look structurally identical under the hood. This step-by-step guide builds a minimal AST clone detector in Python, explains where it breaks, and shows how production tools like Codequiry stack structural, token‑level, and web‑origin checks to catch the copying that student‑grade normalizers miss.

How UMass Amherst Brought AI Detection Into CS 121 General 7 min
Rachel Foster Rachel Foster 1 month ago

How UMass Amherst Brought AI Detection Into CS 121

When 800 students enroll in an introductory Python course, detecting AI-generated code by hand is impossible. UMass Amherst integrated an AI code detector trained on student-level patterns alongside traditional similarity checks—and uncovered a 14% AI flag rate, a 2% false positive rate, and a sustainable workflow that kept TAs focused on teaching rather than policing.

Across Two Semesters, AI Code Detector Accuracy Hit 87% in Python General 7 min
Rachel Foster Rachel Foster 2 months ago

Across Two Semesters, AI Code Detector Accuracy Hit 87% in Python

A two-semester experiment at a mid-sized CS department put Codequiry’s AI code detector to the test across 1,200 student submissions. The tool achieved 87% overall accuracy in identifying AI-generated Python code, with a manageable false-positive rate and strong recall. The study surfaced distinct patterns in where detection excels—and where manual judgment remains essential.

How Code Fingerprints Catch GPL License Violations General 9 min
Rachel Foster Rachel Foster 2 months ago

How Code Fingerprints Catch GPL License Violations

Detecting GPL license violations in a codebase requires more than grep. Code fingerprinting and AST-based similarity analysis can identify copied open-source code even after heavy modification. This article explains the techniques behind automated license compliance detection and how enterprises use them to avoid lawsuits.

Inside a Startup’s Codebase License Compliance Audit General 8 min
Rachel Foster Rachel Foster 2 months ago

Inside a Startup’s Codebase License Compliance Audit

When a fintech startup faced a pre-funding due diligence request, they discovered copies of GPL-licensed libraries scattered across their proprietary codebase. This case study follows their eight-week audit, blending automated scanning tools like Codequiry and FOSSology with manual triage to achieve compliance without derailing their development roadmap.

How Cross-Language Code Plagiarism Detection Actually Works General 10 min
Rachel Foster Rachel Foster 4 months ago

How Cross-Language Code Plagiarism Detection Actually Works

Cross-language code plagiarism presents a growing challenge for programming educators as students discover they can translate solutions between languages to evade detection. This article explains the techniques—AST normalization, semantic fingerprinting, and intermediate representation comparison—that modern tools use to catch these sophisticated cases.