diff --git a/.gitignore b/.gitignore
index 47359fe1..6eedb6a5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -65,3 +65,6 @@ Thumbs.db
 tmp/
 temp/
 *.tmp
+
+# Claude Code worktrees (本地使用，不需提交)
+.claude/worktrees/
diff --git a/apps/api/src/repositories/__init__.py b/apps/api/src/repositories/__init__.py
index 22e44121..c359102f 100644
--- a/apps/api/src/repositories/__init__.py
+++ b/apps/api/src/repositories/__init__.py
@@ -18,9 +18,24 @@ from src.repositories.interfaces import (
     IIncidentRepository,
     ITimelineRepository,
 )
+from src.repositories.approval_repository import (
+    ApprovalDBRepository,
+    get_approval_repository,
+)
+from src.repositories.incident_repository import (
+    IncidentDBRepository,
+    get_incident_repository,
+)
 
 __all__ = [
+    # Interfaces
     "IApprovalRepository",
     "IIncidentRepository",
     "ITimelineRepository",
+    # Implementations
+    "ApprovalDBRepository",
+    "IncidentDBRepository",
+    # Getters
+    "get_approval_repository",
+    "get_incident_repository",
 ]
diff --git a/apps/api/src/repositories/approval_repository.py b/apps/api/src/repositories/approval_repository.py
new file mode 100644
index 00000000..b38ead10
--- /dev/null
+++ b/apps/api/src/repositories/approval_repository.py
@@ -0,0 +1,288 @@
+"""
+Approval Repository - PostgreSQL 實作
+======================================
+Phase 16 R3.3: Repository 層實作
+
+職責: ApprovalRecord 的 CRUD 操作
+設計: 實作 IApprovalRepository Protocol
+
+版本: v1.0
+建立: 2026-03-26 (台北時區)
+建立者: Claude Code (Phase 16 架構重構)
+"""
+
+from datetime import UTC, datetime
+from typing import Any
+from uuid import UUID
+
+import structlog
+from sqlalchemy import select, update
+
+from src.db.base import get_db_context
+from src.db.models import ApprovalRecord
+from src.models.approval import (
+    ApprovalRequest,
+    ApprovalRequestCreate,
+    ApprovalStatus,
+    BlastRadius,
+    DataImpact,
+    DryRunCheck,
+    RiskLevel,
+    Signature,
+)
+from src.repositories.interfaces import IApprovalRepository
+
+logger = structlog.get_logger(__name__)
+
+
+# =============================================================================
+# Conversion Helpers
+# =============================================================================
+
+def _record_to_request(record: ApprovalRecord) -> ApprovalRequest:
+    """Convert DB ApprovalRecord to Pydantic ApprovalRequest"""
+    blast_radius = None
+    if record.blast_radius:
+        br = record.blast_radius
+        blast_radius = BlastRadius(
+            affected_pods=br.get("affected_pods", 0),
+            estimated_downtime=br.get("estimated_downtime", "0"),
+            related_services=br.get("related_services", []),
+            data_impact=DataImpact(br.get("data_impact", "none").lower())
+            if br.get("data_impact")
+            else DataImpact.NONE,
+        )
+
+    dry_run_checks = []
+    if record.dry_run_checks:
+        for check in record.dry_run_checks:
+            dry_run_checks.append(
+                DryRunCheck(
+                    name=check.get("name", ""),
+                    passed=check.get("passed", True),
+                    message=check.get("message"),
+                )
+            )
+
+    signatures = []
+    if record.signatures:
+        for sig in record.signatures:
+            signatures.append(
+                Signature(
+                    signer_id=sig.get("signer_id", ""),
+                    signer_name=sig.get("signer_name", ""),
+                    timestamp=datetime.fromisoformat(sig["timestamp"])
+                    if sig.get("timestamp")
+                    else datetime.now(UTC),
+                    comment=sig.get("comment"),
+                )
+            )
+
+    return ApprovalRequest(
+        id=UUID(record.id),
+        action=record.action,
+        description=record.description,
+        status=ApprovalStatus(
+            record.status.value if hasattr(record.status, "value") else record.status
+        ),
+        risk_level=RiskLevel(
+            record.risk_level.value
+            if hasattr(record.risk_level, "value")
+            else record.risk_level
+        ),
+        blast_radius=blast_radius,
+        dry_run_checks=dry_run_checks,
+        required_signatures=record.required_signatures,
+        current_signatures=record.current_signatures,
+        signatures=signatures,
+        requested_by=record.requested_by,
+        created_at=record.created_at,
+        expires_at=record.expires_at,
+        resolved_at=record.resolved_at,
+        rejection_reason=record.rejection_reason,
+        metadata=record.extra_metadata,
+        fingerprint=record.fingerprint,
+        hit_count=record.hit_count,
+        last_seen_at=record.last_seen_at,
+    )
+
+
+# =============================================================================
+# ApprovalDBRepository
+# =============================================================================
+
+class ApprovalDBRepository(IApprovalRepository):
+    """
+    Approval Repository - PostgreSQL 實作
+
+    純 CRUD 操作，不含業務邏輯
+    業務邏輯請放在 Service 層
+    """
+
+    async def create(
+        self,
+        data: dict[str, Any],
+    ) -> ApprovalRequest:
+        """建立新的 Approval Record"""
+        async with get_db_context() as db:
+            record = ApprovalRecord(**data)
+            db.add(record)
+            await db.flush()
+            await db.refresh(record)
+
+            logger.debug(
+                "approval_created",
+                id=record.id,
+                status=record.status,
+            )
+
+            return _record_to_request(record)
+
+    async def get_by_id(self, approval_id: UUID) -> ApprovalRequest | None:
+        """根據 ID 取得 Approval"""
+        async with get_db_context() as db:
+            result = await db.execute(
+                select(ApprovalRecord).where(ApprovalRecord.id == str(approval_id))
+            )
+            record = result.scalar_one_or_none()
+            return _record_to_request(record) if record else None
+
+    async def get_pending(self) -> list[ApprovalRequest]:
+        """取得所有待審核的 Approval"""
+        async with get_db_context() as db:
+            result = await db.execute(
+                select(ApprovalRecord)
+                .where(ApprovalRecord.status == ApprovalStatus.PENDING)
+                .order_by(ApprovalRecord.created_at.desc())
+            )
+            records = result.scalars().all()
+            return [_record_to_request(r) for r in records]
+
+    async def update_status(
+        self,
+        approval_id: UUID,
+        status: ApprovalStatus,
+        actor: str | None = None,
+    ) -> ApprovalRequest | None:
+        """更新 Approval 狀態"""
+        async with get_db_context() as db:
+            result = await db.execute(
+                select(ApprovalRecord).where(ApprovalRecord.id == str(approval_id))
+            )
+            record = result.scalar_one_or_none()
+
+            if not record:
+                return None
+
+            record.status = status
+            if status in (ApprovalStatus.APPROVED, ApprovalStatus.REJECTED):
+                record.resolved_at = datetime.now(UTC)
+
+            await db.flush()
+            await db.refresh(record)
+
+            logger.info(
+                "approval_status_updated",
+                id=str(approval_id),
+                status=status.value,
+                actor=actor,
+            )
+
+            return _record_to_request(record)
+
+    async def add_signature(
+        self,
+        approval_id: UUID,
+        signer: str,
+        decision: str,
+        comment: str | None = None,
+    ) -> ApprovalRequest | None:
+        """新增簽核"""
+        async with get_db_context() as db:
+            result = await db.execute(
+                select(ApprovalRecord).where(ApprovalRecord.id == str(approval_id))
+            )
+            record = result.scalar_one_or_none()
+
+            if not record:
+                return None
+
+            # 新增簽名
+            new_signature = {
+                "signer_id": signer,
+                "signer_name": signer,
+                "timestamp": datetime.now(UTC).isoformat(),
+                "decision": decision,
+                "comment": comment,
+            }
+
+            signatures = record.signatures or []
+            signatures.append(new_signature)
+            record.signatures = signatures
+            record.current_signatures = len(signatures)
+
+            await db.flush()
+            await db.refresh(record)
+
+            logger.info(
+                "signature_added",
+                id=str(approval_id),
+                signer=signer,
+                decision=decision,
+                total_signatures=record.current_signatures,
+            )
+
+            return _record_to_request(record)
+
+    async def find_by_fingerprint(
+        self,
+        fingerprint: str,
+    ) -> ApprovalRequest | None:
+        """根據指紋查找 Approval (告警收斂用)"""
+        async with get_db_context() as db:
+            result = await db.execute(
+                select(ApprovalRecord)
+                .where(ApprovalRecord.fingerprint == fingerprint)
+                .where(ApprovalRecord.status == ApprovalStatus.PENDING)
+                .order_by(ApprovalRecord.created_at.desc())
+                .limit(1)
+            )
+            record = result.scalar_one_or_none()
+            return _record_to_request(record) if record else None
+
+    async def increment_hit_count(
+        self,
+        approval_id: UUID,
+    ) -> ApprovalRequest | None:
+        """增加 hit_count (告警收斂用)"""
+        async with get_db_context() as db:
+            result = await db.execute(
+                select(ApprovalRecord).where(ApprovalRecord.id == str(approval_id))
+            )
+            record = result.scalar_one_or_none()
+
+            if not record:
+                return None
+
+            record.hit_count = (record.hit_count or 0) + 1
+            record.last_seen_at = datetime.now(UTC)
+
+            await db.flush()
+            await db.refresh(record)
+
+            return _record_to_request(record)
+
+
+# =============================================================================
+# Singleton
+# =============================================================================
+
+_approval_repository: ApprovalDBRepository | None = None
+
+
+def get_approval_repository() -> ApprovalDBRepository:
+    """取得 ApprovalDBRepository 實例 (Singleton)"""
+    global _approval_repository
+    if _approval_repository is None:
+        _approval_repository = ApprovalDBRepository()
+    return _approval_repository
diff --git a/apps/api/src/repositories/incident_repository.py b/apps/api/src/repositories/incident_repository.py
new file mode 100644
index 00000000..c36bb2af
--- /dev/null
+++ b/apps/api/src/repositories/incident_repository.py
@@ -0,0 +1,177 @@
+"""
+Incident Repository - PostgreSQL 實作
+======================================
+Phase 16 R3.3: Repository 層實作
+
+職責: IncidentRecord 的 CRUD 操作
+設計: 實作 IIncidentRepository Protocol
+
+版本: v1.0
+建立: 2026-03-26 (台北時區)
+建立者: Claude Code (Phase 16 架構重構)
+"""
+
+from datetime import UTC, datetime
+from typing import Any
+
+import structlog
+from sqlalchemy import select
+
+from src.db.base import get_db_context
+from src.db.models import IncidentRecord
+from src.models.incident import Incident, IncidentStatus, Severity
+from src.repositories.interfaces import IIncidentRepository
+
+logger = structlog.get_logger(__name__)
+
+
+# =============================================================================
+# Conversion Helpers
+# =============================================================================
+
+def _record_to_incident(record: IncidentRecord) -> Incident:
+    """Convert DB IncidentRecord to Pydantic Incident"""
+    return Incident(
+        incident_id=record.incident_id,
+        status=IncidentStatus(record.status),
+        severity=Severity(record.severity),
+        signals=record.signals or [],
+        affected_services=record.affected_services or [],
+        proposal_ids=record.proposal_ids or [],
+        created_at=record.created_at,
+        updated_at=record.updated_at,
+        resolved_at=record.resolved_at,
+        closed_at=record.closed_at,
+    )
+
+
+def _incident_to_record_data(incident: Incident) -> dict[str, Any]:
+    """Convert Pydantic Incident to dict for DB record"""
+    return {
+        "incident_id": incident.incident_id,
+        "status": incident.status.value,
+        "severity": incident.severity.value,
+        "signals": [s.model_dump() for s in incident.signals],
+        "affected_services": incident.affected_services,
+        "proposal_ids": incident.proposal_ids,
+        "created_at": incident.created_at,
+        "updated_at": incident.updated_at,
+        "resolved_at": incident.resolved_at,
+        "closed_at": incident.closed_at,
+    }
+
+
+# =============================================================================
+# IncidentDBRepository
+# =============================================================================
+
+class IncidentDBRepository(IIncidentRepository):
+    """
+    Incident Repository - PostgreSQL 實作
+
+    純 CRUD 操作，不含業務邏輯
+    業務邏輯請放在 Service 層或 Engine
+    """
+
+    async def create(self, incident: Incident) -> Incident:
+        """建立新的 Incident Record"""
+        async with get_db_context() as db:
+            data = _incident_to_record_data(incident)
+            record = IncidentRecord(**data)
+            db.add(record)
+            await db.flush()
+            await db.refresh(record)
+
+            logger.debug(
+                "incident_created_db",
+                incident_id=record.incident_id,
+                status=record.status,
+            )
+
+            return _record_to_incident(record)
+
+    async def get_by_id(self, incident_id: str) -> Incident | None:
+        """根據 ID 取得 Incident"""
+        async with get_db_context() as db:
+            result = await db.execute(
+                select(IncidentRecord).where(
+                    IncidentRecord.incident_id == incident_id
+                )
+            )
+            record = result.scalar_one_or_none()
+            return _record_to_incident(record) if record else None
+
+    async def get_active(self) -> list[Incident]:
+        """取得所有活躍的 Incident"""
+        active_statuses = [
+            IncidentStatus.INVESTIGATING.value,
+            IncidentStatus.MITIGATING.value,
+        ]
+        async with get_db_context() as db:
+            result = await db.execute(
+                select(IncidentRecord)
+                .where(IncidentRecord.status.in_(active_statuses))
+                .order_by(IncidentRecord.created_at.desc())
+            )
+            records = result.scalars().all()
+            return [_record_to_incident(r) for r in records]
+
+    async def update(self, incident: Incident) -> Incident | None:
+        """更新 Incident"""
+        async with get_db_context() as db:
+            result = await db.execute(
+                select(IncidentRecord).where(
+                    IncidentRecord.incident_id == incident.incident_id
+                )
+            )
+            record = result.scalar_one_or_none()
+
+            if not record:
+                return None
+
+            # 更新欄位
+            record.status = incident.status.value
+            record.severity = incident.severity.value
+            record.signals = [s.model_dump() for s in incident.signals]
+            record.affected_services = incident.affected_services
+            record.proposal_ids = incident.proposal_ids
+            record.updated_at = datetime.now(UTC)
+            record.resolved_at = incident.resolved_at
+            record.closed_at = incident.closed_at
+
+            await db.flush()
+            await db.refresh(record)
+
+            logger.debug(
+                "incident_updated_db",
+                incident_id=record.incident_id,
+                status=record.status,
+            )
+
+            return _record_to_incident(record)
+
+    async def upsert(self, incident: Incident) -> bool:
+        """Upsert Incident (存在則更新，不存在則建立)"""
+        existing = await self.get_by_id(incident.incident_id)
+
+        if existing:
+            result = await self.update(incident)
+            return result is not None
+        else:
+            result = await self.create(incident)
+            return result is not None
+
+
+# =============================================================================
+# Singleton
+# =============================================================================
+
+_incident_repository: IncidentDBRepository | None = None
+
+
+def get_incident_repository() -> IncidentDBRepository:
+    """取得 IncidentDBRepository 實例 (Singleton)"""
+    global _incident_repository
+    if _incident_repository is None:
+        _incident_repository = IncidentDBRepository()
+    return _incident_repository