go-systematic-debugginglisted

# Go Systematic Debugging Debugging ends at the **first broken invariant**, not at the first plausible explanation. Classify the request as `diagnosis_only` or `fix_authorized`. The active workflow owns diagnostic execution. Inside ledger implementation, stay within [Implementation](../../../docs/spec-first-workflow/phases/implementation.md#feedback-during-coding)'s coding-feedback boundary; a blocker alone does not authorize runtime experiments. During final validation, keep causal repair and its focused rerun together. ## Reliable Signal Establish the smallest reliable signal available for the user's exact symptom. Inspect code and form provisional hypotheses as needed to obtain or refine it. For a local symptom, prefer an agent-runnable reproducer; record what was actually run, its result, and any reproduction limit. For a live incident, capture volatile evidence before restart, signal, rollout, or time can destroy it, and state which side of every boundary the evidence covers. Keep untested explanations provisional and name missing evidence before making a causal claim. ## Causal Loop Minimize further when it improves causal discrimination or materially reduces rerun cost. Choose an experiment that distinguishes plausible causes; isolate the variable or probe whose effect it measures. Track competing hypotheses when several remain or a handoff needs their history, with the evidence that supports, rejects, or blocks each. Walk backward through affected boundaries u