Agent Skills: diagnose-issue

Research and define codebase issues before implementation planning. Use when the user provides an issue statement, bug report, Jira ticket, vague problem, proposed solution, runtime symptom, or design concern and wants Codex to inspect the current codebase, validate whether the problem exists, diagnose likely causes, compare solution directions, and produce an evidence-backed problem definition. Do not use when the user asks for a step-by-step implementation plan, direct implementation, or code review of an existing diff.