[eesmith]

The problem I have with your question is "agile" seems to mean anything except a pure waterfall development model.

Even modified waterfall seems to be described as agile.

As a sole developer of a software product, I haven't figured out how the agile principles even apply to me.

"Individuals and interactions over processes and tools" doesn't work when there's only one person.

"Working software over comprehensive documentation" Does that mean ship code but don't provide comprehensive documentation to my users? No, it means internal process documentation. Which isn't applicable since it's just me.

"Customer collaboration over contract negotiation". That only applies for contract software development. I sell a software product.

"Responding to change over following a plan". I don't have much of a plan, so I guess I do this one. But I do have a long-term vision, since that's essential to figuring out what groundwork to have.

Personally, I learned RAD (rapid application development) when I was a young programmer back in the 1990s, and that's what I still use.

[eurasiantiger]

You, the developer, have one customer: you, the software vendor.

The software vendor sells a software product, not the developer.

[eesmith]

Next, tell me how many angels can dance on the head of a pin.

Assuming your definition makes sense, what are the "interactions ... processes and tools" between me-the-vendor and me-the-developer?

What is the comprehensive documentation that I'm supposed to avoid?

What is the contract negotiation?

[eurasiantiger]

Think about it.

[eesmith]

I've spent over 20 years thinking about it, and not been able to figure it out.

Since it's clear to you, perhaps you can clarify how the Agile Manifesto applies to software product sales when there's a single developer and once-per-year product cycles?

[eurasiantiger]

Well, you do have a process there already — the release cycle. Why once per year?

[eesmith]

Sure, I have a process. I have 10K+ unit tests run across multiple OSes and Python versions, I have a checklist for release, and more.

But if "a process" is all that's needed to be Agile then waterfall is Agile.

Why not once a year? Does Agile require a higher delivery frequency than that?

That is, how is your question relevant to the topic?