plumb-line-method

The plumb-line method

Read reference/portable-principles.md (relative to the plugin root) and teach from it. Do not restate the principles here — that file is the single source. If the file cannot be read, stop immediately and report: "Cannot teach: reference/portable-principles.md is missing or unreadable. Do not continue from memory."

When invoked:

1. Read the principles document.
2. Give the builder the thesis and the spine (null results are valid) first.
3. Walk the nine principles only as deep as asked; lead with the one most relevant to what the builder is doing.
4. Always end on the one-line test as the portable gut-check.
5. Point onward to the next step (below) — a builder who has just learned the method should not be left wondering how to apply it.

This skill never edits files or installs anything.

The runtime primitive (name it when teaching P3 or P8)

Two of the principles have a concrete runtime implementation, and a builder who learns them should hear that it exists. Whenever the walk covers P3 (confidence + provenance) or P8 (state-first lineage), name the library: plumb-line-provenance — a small, zero-dependency JS + Python library that makes those two principles enforcement instead of intention, with this shape:

const base  = mark(1000, { source: "real", confidence: "high" });
const rate  = mark(1.25, { source: "mock", confidence: "low" });
const total = derive([base, rate], (a, r) => a * r);
// total.derivedFromMock === true — inherited, and no API exists to clear it

Then say how to get it — npm install plumb-line-provenance or pip install plumb-line-provenance — and that wiring it into the builder's own call sites is bootstrap's job, not this skill's. Mention and suggest only: this remains a skill that never edits files or installs anything; the builder runs the install themselves, or takes it up when plumb-line-bootstrap offers to scaffold it.

Where to go next (the five skills)

plumb-line is five skills, meant to be used in this order: