atgreen Walking Skeleton
Overview
Core principle: Get the thinnest possible slice running end to end first — input to visible output, all the way through — before you flesh out any single part.
A walking skeleton is a system that does almost nothing but does it completely: every layer is present, wired together, and runs, even if each layer is a stub returning a hard-coded value. It walks. Then you grow muscle onto a skeleton that already stands, instead of assembling a pile of perfect bones that have never held weight together.
Why It Wins
The risk in anything new is rarely a single component — it's the connections: the layers that must talk, the assumptions that don't survive contact, the "obvious" integration that isn't. A walking skeleton pays down that risk on day one. A pile of polished-but-unconnected parts defers it to the worst possible moment: the end.
The Recipe
- Trace the thinnest line from a real input to a visible output. List every layer it must pass through. Keep the line as short as you can while still touching every layer.
- Stub every layer to the minimum that lets the line run. Hard-code returns. Fake the data. Print instead of persist. The goal is a pulse, not a feature.
- Wire it together and run it. Watch the input travel all the way to output. This is the moment that matters — the system walks.
- Only now, grow one layer at a time. Replace a stub with the real thing, run again, confirm it still walks. Repeat. The skeleton stays alive through every step.
Quick Reference
| Do | Don't |
|---|---|
| Touch every layer, shallowly | Perfect one layer, deeply |
| Hard-code, stub, fake — to get a pulse | Build real data models up front |
| Run end to end before anything is "real" | Wait until parts are done to connect them |
| Grow one stub into real code at a time | Replace many stubs in one leap |
Signs You Skipped This
- You have three "done" components and nothing runs.
- You're deep in the interesting module and haven't proven the boring integration works.
- The first end-to-end run is scheduled for "once the pieces are ready" — i.e., never, until crunch.
- You can describe how it will work but can't show it doing anything.
Any of these: stop adding. Wire what exists into a slice that runs, however fake.
Relationship to Other Skills
The builder persona starts here by default. When a layer hides a genuine unknown ("can this even be done?"), retire it with spike-and-stabilize before growing it for real.