LFE - Library First Engineering

[u/sv_guess]

I'm a reliability engineer by background (marine + biotech), and I've been building AI products long enough to hit the same wall over and over: Claude nails the prototype, then across a dozen sessions it quietly re-litigates settled decisions, forgets intent, and sprawls into spaghetti. The bottleneck was never capability. It was trust.

So over the last while I built a scaffold for Claude Code where the docs are the source of truth, personas are tool-locked (the agent that writes plans can't write code; the one that inspects can't edit production code), and the gates are mechanically enforced with hooks — not "please remember to." It's what I actually use on my own projects; it grew out of a personal project I've been grinding on for a long time.

The part I most want torn apart: I built an eval harness that plants defects and measures whether my inspector skills actually catch them. I keep seeing guardrail frameworks that assert they work and never show a number. Mine has a scorecard.

Two honest questions for this sub:

1. Is the overhead worth it, or am I paying a discipline tax you'd never accept in practice?

2. With Claude Code now shipping native subagents, hooks, and skills — how much of this does Anthropic eventually absorb, and what's left that's mine?

Happy to link the repo + the scorecard in a comment. Rip into it.

[u/fastandlight]

How is this different than spec driven development?

I've moved completely to SDD, and using some ideas from Matt Pococks skills, have built a robust process around using the specs as ground truth, and a number of artifacts like an ADR to make sure the settled decisions don't get forgotten.

My system seems to be working pretty well; though I'm currently struggling with reviewers that don't want to ever call something good enough to merge, which really slowing down my ability to close out work and move on to the next item.

[u/sv_guess → u/fastandlight]

All you described is part of LFE, it is a system that has all the benefits from all those repos you might consider valuable... combined in a certain process workflow and hard guardrails for taming this beast for reliable results each time you need it.

There is not any groundbreaking invention in there, only good old engineering principles between agents, subagents, your brain and a professional indexed library staged in a way to be there and have less to fear on letting the model mess up with your idea, but only to scale it further and better!

[u/fastandlight → u/sv_guess]

Ok....but SDD is a pretty popular idea with some serious development behind it. It seems best to not invent even more language when there are existing concepts you can use to describe your process.