How to bring back a program whose source is gone

A hands-on run that attaches a reverse-engineering toolkit — one that takes a finished program apart and recovers its structure — to a coding agent. On a request the toolkit runs the specialist analyzers on your behalf and returns three things: a blueprint a person can read, the grounds for judging it that way, and the parts still unknown; the agent then writes code from those, runs it, and asks again about the unknown parts. The analyzers inside have been in use for more than 20 years, so what is new is not the technology but the connection. In a comparison that gave the same task to one side using the tools and one side not, results were nearly the same on the web side, where the code comes down as is, and the place where it paid off was installed programs a person cannot read. The place to use it is named as in-house programs built by an outside contractor long ago, with neither the builder nor the source left; for programs sold by others, the terms often forbid reverse engineering, so the scope has to be limited.

This is a note: my own write-up after reading several sources. It has no source link; events checked against a source are kept as records.