Na0S (AI Prompt Injection Detector)
Developed an open-source prompt-injection detector that screens LLM inputs and evaluates detection performance against structured test sets. Fused rule-based and ML signals across a taxonomy and measured effectiveness using held-out canary data. Red-teamed the detector by creating an evasion harness to perturb attacks and re-score them on a committed reproducible benchmark. • Achieved 0.925 F1 with zero false positives on a held-out 230-sample canary set (115 hard negatives). • Combined 120 rules with a three-signal ML ensemble (TF-IDF/logistic regression, all-MiniLM-L6-v2, Meta Prompt-Guard-2). • Quantified bypass rates under lightweight obfuscations (leetspeak, spacing, typos) using the evasion harness. • Versioned the data pipeline with DVC and used a fact-extractor backed by a 9,300-test suite to regenerate metrics from source.