A recreated screen can look familiar before any of the hard behavior exists. A recovered function can be correct while the surrounding application remains unfinished. Both can be useful, as long as you describe what you actually have.
Four layers worth separating
The interface is what a person sees. Client behavior is what the browser or local application does. Remote behavior belongs to services outside that artifact. Product reliability includes all the states, failures and operational work that make the whole thing dependable.
REA can help an agent investigate available artifacts and observations. The scope of that access determines what the findings can establish. A local package cannot reveal a private service’s implementation simply because the interface talks to it.
A reconstruction is a new implementation
Native pseudocode is an analysis result, not a restored copy of the author’s original source. A useful agent can turn findings into readable code, but that code needs its own tests and design decisions.
Original names, comments, build history and unobserved requirements may be missing. In a JavaScript package, more source-level detail may remain, but minification, dynamic behavior and unavailable dependencies can still leave gaps.
Those limitations do not make the exercise pointless. They tell you which conclusions are supported and which need another probe.
What “it works” needs to mean
Pick the behavior before judging the result. For an exporter, does the file parse correctly? Does it preserve multiline content? What happens when the dialog is cancelled or the disk write fails?
For a small native calculation, compare outputs across a defined domain. For a browser feature, check the state transition and the response it depends on. A working happy-path demo is a useful checkpoint, but it is not the end of validation.
This is why the DX-Ball sound-pan case is instructive: its comparison has a specific target, function and test scope.
Local analysis and model access are different questions
The project describes local target analysis. Your coding agent still receives tool results, and its model provider and client have their own data handling. Do not interpret “local” as a blanket guarantee that every piece of information stays on your machine.
For tutorials, use public or self-created fixtures and keep credentials and personal records out of captures. The method should be reproducible without a reader exposing private data.
Choose an investigation you can finish
A good first target has a small input, an observable result, an available artifact and a check you can perform. A format conversion, an export route or a simple numeric rule usually gives you a clearer finish line than a complete service.
Stop broad exploration when the original question is answered. Record remaining unknowns instead of letting them silently become features the agent invents. Then decide whether another investigation is worth doing.
A practical starting point
If your question is “could I understand something like this?”, try the Pocket Notes export lab. It has a retained REA report, readable files and an explicit static-analysis boundary.
If your question is “could I ship a replacement?”, first write the behavior contract, test cases and operational needs. REA findings can inform that work; the product decisions still belong to you.