Regression Sentinel

Regression Sentinel

Prerequisites & Dependencies

• Python 3.10+ (for checkpoint orchestration)
• Access to verification output from verify-orchestrator (exit codes, assertion outputs)
• No external runtime dependencies

Execution Steps

1. Capture checkpoints: After each task completion where verify-orchestrator returns VERIFIED, persist the verification result as a checkpoint:

   • Task ID or description
   • Verification status (VERIFIED)
   • Exit code and output snippet
   • Timestamp

2. Store checkpoints: Write checkpoint data to regression-checkpoints.json at the repository root:

   [
     {"task_id": "task-1", "status": "VERIFIED", "exit_code": 0, "output": "...", "timestamp": "2026-09-11T10:00:00Z"},
     {"task_id": "task-2", "status": "VERIFIED", "exit_code": 0, "output": "...", "timestamp": "2026-09-11T10:30:00Z"}
   ]
   

3. Before each new task: Read the latest N checkpoints (default N=5) from regression-checkpoints.json and execute the same verification commands as smoke tests.

4. Classify results:

   • All checkpoints pass → proceed with new task as normal
   • Any checkpoint fails → halt the new task and surface the regression with diff highlighting
   • No checkpoints exist → first task in session; skip smoke suite

5. Regression report: On detection, generate a diff report showing:

   • What changed between the last VERIFIED state and current state
   • Which checkpoint(s) failed and why
   • Recommended remediation steps

Checkpoint Workflow Example

Task 1 completes → verify-orchestrator → VERIFIED → save checkpoint
Task 2 begins → regression-sentinel reads 1 checkpoint → runs same test → passes → proceed
Task 3 begins → regression-sentinel reads 2 checkpoints → one fails → halt, show diff

Windows PowerShell Notes

• Checkpoints stored as regression-checkpoints.json with UTF8NoBOM encoding
• Smoke test commands extracted from prior verify-orchestrator output
• Use Get-ChildItem for mtime-based checkpoint pruning (remove older than N days)