The structural integrity of steel can be dramatically impacted by corrosion. As such, efforts are often taken during production to minimize the process (e.g., application of protective coatings). Corrosion pits are very small holes that develop in a metal (e.g., steel) as a result of oxidation. From the surface, they are extremely difficult to detect. Inside, however, they are capable of damaging the structural integrity of the metal by contributing to weak spots (e.g., fatigue cracks) that decrease the material’s lifespan. Identifying corrosion pits early is key to preventing rapid structural degradation. This phage-based method to identify and repair nanoscale defects in surface materials ultimately enhances the quality control and inspection of metal samples, reducing future engineering failures and economic burden.