diagnoselisted

# Diagnose Build a mental model and check recorded constraints before probing. Work in order; record why any phase is skipped. ## Iron law ```text NO FIX WITHOUT A REPRODUCTION AND A ROOT CAUSE FIRST ``` Diagnosis is read-only except temporary instrumentation. Permanent repair requires an explicit user request or an authorised `implement` scope. ## Workflow 1. **Feedback loop.** Create the fastest sharp signal that reaches the reported failure: failing test, CLI/HTTP/browser fixture, replay, property loop, bisection, differential harness or structured user loop. Pin time/randomness and isolate mutable dependencies. For flakes, raise the reproduction rate. If no useful loop is possible, stop and request the missing environment or artifact; do not guess. 2. **Reproduce.** Confirm repeated runs show the user's exact symptom, not a nearby failure. Capture the observation needed to prove later repair. 3. **Hypothesise.** Rank 3–5 falsifiable causes before testing. Each needs a distinct prediction; inspect recent diffs, deploys and dependency changes. 4. **Instrument.** Map one probe to one prediction and vary one thing at a time. Prefer debugger/breakpoints; tag targeted temporary logs uniquely. Performance work starts with baseline, profile and bisect. 5. **Handoff or fix.** Without repair authority, stop with root cause, confidence, affected paths and the proposed regression seam. With authority, first turn the repro into a failing test at