Test-driven development with an LLM for fun and profit

One trend I've noticed, framed as a logical deduction:

1. Coding assistants based on o1 and Sonnet are pretty great at coding with <50k context, but degrade rapidly beyond that.

2. Coding agents do massively better when they have a test-driven reward signal.

3. If a problem can be framed in a way that a coding agent can solve, that speeds up development at least 10x from the base case of human + assistant.

4. From (1)-(3), if you can get all the necessary context into 50k tokens and measure progress via tests, you can speed up development by 10x.

5. Therefore all new development should be microservices written from scratch and interacting via cleanly defined APIs.

Sure enough, I see HN projects evolving in that direction.

So having clear requirements, a focused purpose for software, and a clear boundary of software responsibility makes for a software development task that can be accomplished?

If only people had figured out at some point that the same thing applies when communicating to human software engineers.

If human software engineers refused to work unless those conditions were met, what a wonderful world it would be.

They do implicitly: you can only be accidentally productive without those preconditions.