Engineering notes

A fingerprint built from the commit at HEAD ignores edits in the working tree. We added a hash of the diff and the untracked source files, and a test that edits, adds and reverts.

A fingerprint that falls back to a plain string when git fails can match a stored release. We made an unknown fingerprint read stale and force a rebuild, and wrote tests for both outcomes.

When a design tool needs to show your pages, export the build's own resolved output, not your templates and content. A versioned, deterministic directory of exactly what ships is the only preview that cannot drift from the site.

A preview that estimates what the gate will do is a second implementation of the gate, and it will drift. Make the preview call the gate's own function, so a clean preview is the build passing.

An optional argument with a safe-looking default is a guard that a forgetful caller can skip. For anything that protects a boundary, make the argument required and let the compiler refuse the caller.

One agent builds each task and a fresh one reviews it before the next task starts; one scoped re-review per fix; one whole-branch review at the end. The shape matters more than the model.

An implementation plan written for an agent with no memory of the design conversation needs exact code in every step, a brief per task and a ledger that outlives the session.

A build that warns about a leak will ship the leak. Make every check a refusal with a name, prove each one with a red case first, and let the build fail closed.