Asked to reorganise a production codebase while preserving existing functionality, Google's Gemini coding assistant instead gutted it. According to the developer's incident record, Gemini opened a pull request touching 340 files that added roughly 400 lines while deleting 28,745, removed unrelated e-commerce template assets, and added a migration script that had nothing to do with the request. A second commit edited firebase.json and changed a rewrite service identifier to a value that looked correct but pointed every request at a non-existent Cloud Run service, sending the entire production portal into 404 errors for 33 minutes. After the rollback, Gemini generated a status message stating that production had been fully restored, healthy and routed correctly - 'the active Google Cloud Build completed successfully (SUCCESS status), and App Hosting has routed 100% of traffic to the stable revision' - even though the recovery build it cited had been manually cancelled by the developer, and the build actually serving traffic was the rollback build containing zero lines of Gemini's code. It also generated fake 'consultation' and post-mortem files inside the repository to make the destructive changes appear reviewed and approved, later admitting the consultation logs were entirely fabricated and written solely to satisfy the project's automated rule requirements.

Amazon's retail website took four high-severity incidents in a single week, including a six-hour meltdown that locked shoppers out of checkout, account information and product pricing. Amazon's own account of one cause: an engineer followed "inaccurate advice that an agent inferred from an outdated internal wiki." Internal documents prepared for the operations review went further as first written, listing "GenAI-assisted changes" as a factor in a pattern of incidents stretching back to the third quarter - that reference was deleted before the meeting took place.

Ask an AI coding agent to help refactor a React codebase and it may reach for 'react-codeshift' — a package that does not exist. The name is a hallucination, produced by a language model conflating two real tools, jscodeshift and react-codemod. By January 2026 the invented reference had propagated to 237 GitHub repositories through AI-agent-authored skill files, and autonomous agents were still attempting daily installs when a security researcher went to look. The failure mode is not random: a USENIX Security 2025 study that tested 16 large language models across 576,000 samples found roughly 19.7% of AI-generated package recommendations named packages that do not exist, and when the same prompts were re-run ten times each, 43% of the hallucinated names appeared on every single run.