# dd0c/cost — Epic Addendum (BMad Review Findings)

**Source:** BMad Code Review (March 1, 2026)
**Approach:** Surgical additions to existing epics — no new epics created.

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## Epic 2 Addendum: Anomaly Detection Engine

### Story 2.8: Concurrent Baseline Update Conflict Resolution
As a reliable anomaly detector, I want concurrent Lambda invocations updating the same baseline to converge correctly via DynamoDB conditional writes, so that Welford running stats are never corrupted.

**Acceptance Criteria:**
- Two simultaneous updates to the same baseline both succeed (one retries via ConditionalCheckFailed).
- Final baseline count reflects both observations.
- Retry reads fresh baseline before re-applying the update.

**Estimate:** 2 points

### Story 2.9: Property-Based Anomaly Scorer Validation (10K runs)
As a mathematically sound anomaly detector, I want the scorer validated with 10K property-based test runs, so that edge cases in the scoring function are caught before launch.

**Acceptance Criteria:**
- Score is always between 0 and 100 for any valid input (10K runs, seed=42).
- Score monotonically increases as cost increases (10K runs).
- Reproducible via fixed seed.

**Estimate:** 1 point

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## Epic 3 Addendum: Notification Service

### Story 3.7: Remediation RBAC (Slack Action Authorization)
As a security-conscious operator, I want only account owners to trigger destructive remediation actions (Stop Instance), so that a random Slack viewer can't shut down production.

**Acceptance Criteria:**
- Owner role can trigger "Stop Instance" (200).
- Viewer role gets 403 with "insufficient permissions".
- User from different Slack workspace gets 403.
- Non-destructive actions (snooze, mark-expected) allowed for all authenticated users.

**Estimate:** 2 points

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## Epic 4 Addendum: Customer Onboarding

### Story 4.7: Clock Interface for Governance Tests
As a testable governance engine, I want time-dependent logic (14-day auto-promotion) to use an injectable Clock interface, so that governance tests are deterministic and don't depend on wall-clock time.

**Acceptance Criteria:**
- `FakeClock` can be injected into `GovernanceEngine`.
- Day 13: no promotion. Day 15 + low FP rate: promotion. Day 15 + high FP rate: no promotion.
- No `Date.now()` calls in governance logic — all via Clock interface.

**Estimate:** 1 point

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## Epic 8 Addendum: Infrastructure & DevOps

### Story 8.7: Redis Failure Safe Default for Panic Mode
As a resilient platform, I want panic mode checks to default to "active" (safe) when Redis is unreachable, so that a Redis outage doesn't accidentally disable safety controls.

**Acceptance Criteria:**
- Redis disconnect → `checkPanicMode()` returns `true` (panic active).
- Warning logged: "Redis unreachable — defaulting to panic=active".
- Normal operation resumes when Redis reconnects.

**Estimate:** 1 point

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**Total Addendum:** 7 points across 5 stories
