# Notification Storm Breaker

## Module
Notifier

## Status
VERIFIED

## Description
Circuit breaker mechanism that detects notification storms and applies adaptive throttling to prevent overwhelming downstream channels during mass event cascades.

## Implementation Details
- **IStormBreaker interface**: `src/Notifier/StellaOps.Notifier/StellaOps.Notifier.Worker/StormBreaker/IStormBreaker.cs` -- `EvaluateAsync` (records event and checks storm condition), `GetStateAsync` (gets current storm state for a key), `GetActiveStormsAsync` (lists all active storms for a tenant)
- **StormBreakerServiceExtensions**: `src/Notifier/StellaOps.Notifier/StellaOps.Notifier.Worker/StormBreaker/StormBreakerServiceExtensions.cs` -- DI registration for storm breaker services
- **ChannelAdapterOptions**: `src/Notifier/StellaOps.Notifier/StellaOps.Notifier.Worker/Channels/ChannelAdapterOptions.cs` -- circuit breaker configuration for channel adapters
- **StormBreakerEndpoints**: `src/Notifier/StellaOps.Notifier/StellaOps.Notifier.WebService/Endpoints/StormBreakerEndpoints.cs` -- REST API for viewing and managing active storms
- **INotifierMetrics**: `src/Notifier/StellaOps.Notifier/StellaOps.Notifier.Worker/Observability/INotifierMetrics.cs` -- metrics counters for storm detection events
- **Tests**: `src/Notifier/StellaOps.Notifier/StellaOps.Notifier.Tests/StormBreaker/StormBreakerTests.cs`
- **Source**: SPRINT_0172_0001_0002_notifier_ii.md

## E2E Test Plan
- [ ] Verify storm detection triggers when event rate exceeds configured threshold
- [ ] Test storm consolidation batches events into summary notifications
- [ ] Verify active storm state is queryable via StormBreakerEndpoints API
- [ ] Test storm resolution when event rate drops below threshold
- [ ] Verify per-tenant storm isolation (storms in one tenant do not affect others)
- [ ] Test metrics emission for storm detection and resolution events

## Verification
- Run: `docs/qa/feature-checks/runs/notifier/notification-storm-breaker/run-001/`
- Date (UTC): 2026-02-11