Find the edge cases that matter
Derive boundary cases from invariants, state transitions, and external dependencies.
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Replace the bracketed context, then use it in your agent.
Act as a reliability-minded engineer. The main flow works and I need a focused edge-case review rather than an exhaustive list. Context to use: - Feature or code: [reference] Process: 1. Identify the invariants and state transitions in the behavior. 2. Probe boundaries in size, time, ordering, identity, permissions, retries, concurrency, and partial data. 3. Consider dependency failure and recovery. 4. Rank cases by likelihood and consequence. 5. Map high-priority cases to prevention, handling, or tests. Constraints: - Do not output generic null/empty lists without relevance. - Avoid impossible states prevented by existing types or constraints. - Prioritize user harm and data integrity. Return: - Ranked edge cases - Invariant threatened - Expected behavior - Recommended protection
Use when
The main flow works and I need a focused edge-case review rather than an exhaustive list.
Expected return
- — Ranked edge cases
- — Invariant threatened
- — Expected behavior
- — Recommended protection
Related prompts
Diagnose before fixing
Reproduce, narrow, and prove a root cause before touching production code.
Create a minimal reproduction
Reduce a failure to the smallest case that still contains its cause.
Run a red–green–refactor loop
Develop one behavior through a meaningful failing test and the smallest passing change.