I keep coming back to this idea: vibe code is basically instant legacy code.
Not because AI-generated code is necessarily bad, but because it often puts us in a familiar situation: the system works, yet no one fully understands how it works. That makes me wonder whether some of the most useful techniques for vibe coding are actually techniques we already use for legacy systems. For example:
Snapshot / approval tests: capture the current output and require explicit approval when it changes.
Characterization tests: describe what the system actually does today, regardless of what it was originally intended to do.
Golden master tests: run known inputs through the system and compare the results with a trusted baseline.
Contract test: protect the boundaries between components, services, APIs, events, and data stores.
Differential testing: compare two implementations and detect where their behavior diverges.
Test carving: observe a larger execution and extract smaller, focused regression tests from it.
