The Code I Didn’t Read

2026-07-12 · Source: Artificial Intelligence on Medium · Field: Technology & Digital — Software Development & Engineering, Artificial Intelligence & Machine Learning · Depth: Intermediate, quick

Summary

In April, a developer implemented a refund flow for Garther in approximately forty minutes using an AI assistant. The specified logic dictated full refunds for cancellations over 48 hours out, half refunds for those within 48 hours, and no refunds for no-shows. The developer "skimmed" the AI-generated code, which included wiring it to an endpoint and adding tests, before merging it. This rapid development was dubbed "vibe coding." However, five weeks later, a critical bug emerged when a host reported a full refund for a cancellation occurring just nineteen hours before an event, directly contradicting the intended policy. This incident revealed the developer had not thoroughly reviewed the AI-generated code.

Key takeaway

For software engineers integrating AI code generation, you must prioritize comprehensive code review over speed. Your reliance on "vibe coding" and quick merges, even with passing automated tests, risks introducing subtle yet critical bugs like the unhandled refund logic. Always scrutinize AI-generated functions, especially those handling financial transactions or complex business rules, to prevent costly post-deployment issues and maintain system integrity.

Key insights

Over-reliance on AI-generated code without thorough review can introduce critical, hard-to-detect bugs.

Principles

• AI-generated code requires rigorous validation.
• Automated tests don't catch all logic errors.

In practice

• Always read AI-generated code thoroughly.
• Supplement AI tests with manual review.

Topics

• AI Code Generation
• Software Bugs
• Code Review
• AI-Assisted Development
• Refund Systems
• Developer Workflow

Best for: CTO, VP of Engineering/Data, AI Engineer, Software Engineer, Director of AI/ML

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Editorial summary, takeaway, and curation by AIssential. Original article published by Artificial Intelligence on Medium.