Logic-Lens — Fault Locate

Setup

Use lazy loading per ../_shared/common.md §13:

1. Read ../_shared/common.md only for language, Iron Law, Fault Confidence, scope routing, Remedy discipline, config fields, and loading budget.
2. Read only the relevant step in logic-locate-guide.md as you reach it.
3. Load ../_shared/logic-risks.md, ../_shared/semiformal-guide.md, ../_shared/semiformal-checklist.md, and ../_shared/report-template.md on demand when the current step needs them.

Process

Step 0. Language + scope routing. Detect language per common.md §1. Confirm a concrete failure exists (stack trace, failing assertion, specific wrong value). If only a suspicion, switch to logic-review.

Step 1. Understand the failure (guide Step 1) — observed behavior, expected behavior, reproduction path.

Step 2. Identify the entry point (guide Step 2) — failing test, outermost application frame, or request handler — whichever is closest to the failure. Stay inside the failure cone first: stack frames, failing test fixture, directly called local functions, and config/env values read on that path. Do not scan unrelated modules unless the trace crosses into them.

Step 3. Trace backward from the failure point (guide Step 3) — walk each value and state back to its origin, building premises at every hop.