diff --git a/src/db/repositories/index.ts b/src/db/repositories/index.ts
new file mode 100644
index 0000000..5c9166b
--- /dev/null
+++ b/src/db/repositories/index.ts
@@ -0,0 +1,31 @@
+/**
+ * Repository Port Interfaces
+ *
+ * Re-exports all repository port interfaces.
+ * These are the PORTS in hexagonal architecture.
+ * Implementations in ./drizzle/ are ADAPTERS.
+ */
+
+export type {
+  InitiativeRepository,
+  CreateInitiativeData,
+  UpdateInitiativeData,
+} from './initiative-repository.js';
+
+export type {
+  PhaseRepository,
+  CreatePhaseData,
+  UpdatePhaseData,
+} from './phase-repository.js';
+
+export type {
+  PlanRepository,
+  CreatePlanData,
+  UpdatePlanData,
+} from './plan-repository.js';
+
+export type {
+  TaskRepository,
+  CreateTaskData,
+  UpdateTaskData,
+} from './task-repository.js';
diff --git a/src/db/repositories/initiative-repository.ts b/src/db/repositories/initiative-repository.ts
new file mode 100644
index 0000000..f4e4417
--- /dev/null
+++ b/src/db/repositories/initiative-repository.ts
@@ -0,0 +1,60 @@
+/**
+ * Initiative Repository Port Interface
+ *
+ * Port for Initiative aggregate operations.
+ * Implementations (Drizzle, etc.) are adapters.
+ */
+
+import type { Initiative, NewInitiative } from '../schema.js';
+
+/**
+ * Data for creating a new initiative.
+ * Omits system-managed fields (id, createdAt, updatedAt).
+ */
+export type CreateInitiativeData = Omit<NewInitiative, 'id' | 'createdAt' | 'updatedAt'>;
+
+/**
+ * Data for updating an initiative.
+ * Partial of creation data - all fields optional.
+ */
+export type UpdateInitiativeData = Partial<CreateInitiativeData>;
+
+/**
+ * Initiative Repository Port
+ *
+ * Defines operations for the Initiative aggregate.
+ * Only knows about initiatives - no knowledge of child entities.
+ */
+export interface InitiativeRepository {
+  /**
+   * Create a new initiative.
+   * Generates id and sets timestamps automatically.
+   */
+  create(data: CreateInitiativeData): Promise<Initiative>;
+
+  /**
+   * Find an initiative by its ID.
+   * Returns null if not found.
+   */
+  findById(id: string): Promise<Initiative | null>;
+
+  /**
+   * Find all initiatives.
+   * Returns empty array if none exist.
+   */
+  findAll(): Promise<Initiative[]>;
+
+  /**
+   * Update an initiative.
+   * Throws if initiative not found.
+   * Updates updatedAt timestamp automatically.
+   */
+  update(id: string, data: UpdateInitiativeData): Promise<Initiative>;
+
+  /**
+   * Delete an initiative.
+   * Throws if initiative not found.
+   * Cascades to child phases, plans, tasks via FK constraints.
+   */
+  delete(id: string): Promise<void>;
+}
diff --git a/src/db/repositories/phase-repository.ts b/src/db/repositories/phase-repository.ts
new file mode 100644
index 0000000..ff787cf
--- /dev/null
+++ b/src/db/repositories/phase-repository.ts
@@ -0,0 +1,62 @@
+/**
+ * Phase Repository Port Interface
+ *
+ * Port for Phase aggregate operations.
+ * Implementations (Drizzle, etc.) are adapters.
+ */
+
+import type { Phase, NewPhase } from '../schema.js';
+
+/**
+ * Data for creating a new phase.
+ * Omits system-managed fields (id, createdAt, updatedAt).
+ */
+export type CreatePhaseData = Omit<NewPhase, 'id' | 'createdAt' | 'updatedAt'>;
+
+/**
+ * Data for updating a phase.
+ * Partial of creation data - all fields optional.
+ */
+export type UpdatePhaseData = Partial<CreatePhaseData>;
+
+/**
+ * Phase Repository Port
+ *
+ * Defines operations for the Phase aggregate.
+ * Only knows about phases - no knowledge of parent or child entities.
+ */
+export interface PhaseRepository {
+  /**
+   * Create a new phase.
+   * Generates id and sets timestamps automatically.
+   * Foreign key to initiative enforced by database.
+   */
+  create(data: CreatePhaseData): Promise<Phase>;
+
+  /**
+   * Find a phase by its ID.
+   * Returns null if not found.
+   */
+  findById(id: string): Promise<Phase | null>;
+
+  /**
+   * Find all phases for an initiative.
+   * Returns phases ordered by number.
+   * Returns empty array if none exist.
+   */
+  findByInitiativeId(initiativeId: string): Promise<Phase[]>;
+
+  /**
+   * Update a phase.
+   * Throws if phase not found.
+   * Updates updatedAt timestamp automatically.
+   */
+  update(id: string, data: UpdatePhaseData): Promise<Phase>;
+
+  /**
+   * Delete a phase.
+   * Throws if phase not found.
+   * Cascades to child plans and tasks via FK constraints.
+   */
+  delete(id: string): Promise<void>;
+}
diff --git a/src/db/repositories/plan-repository.ts b/src/db/repositories/plan-repository.ts
new file mode 100644
index 0000000..1cb3f2a
--- /dev/null
+++ b/src/db/repositories/plan-repository.ts
@@ -0,0 +1,62 @@
+/**
+ * Plan Repository Port Interface
+ *
+ * Port for Plan aggregate operations.
+ * Implementations (Drizzle, etc.) are adapters.
+ */
+
+import type { Plan, NewPlan } from '../schema.js';
+
+/**
+ * Data for creating a new plan.
+ * Omits system-managed fields (id, createdAt, updatedAt).
+ */
+export type CreatePlanData = Omit<NewPlan, 'id' | 'createdAt' | 'updatedAt'>;
+
+/**
+ * Data for updating a plan.
+ * Partial of creation data - all fields optional.
+ */
+export type UpdatePlanData = Partial<CreatePlanData>;
+
+/**
+ * Plan Repository Port
+ *
+ * Defines operations for the Plan aggregate.
+ * Only knows about plans - no knowledge of parent or child entities.
+ */
+export interface PlanRepository {
+  /**
+   * Create a new plan.
+   * Generates id and sets timestamps automatically.
+   * Foreign key to phase enforced by database.
+   */
+  create(data: CreatePlanData): Promise<Plan>;
+
+  /**
+   * Find a plan by its ID.
+   * Returns null if not found.
+   */
+  findById(id: string): Promise<Plan | null>;
+
+  /**
+   * Find all plans for a phase.
+   * Returns plans ordered by number.
+   * Returns empty array if none exist.
+   */
+  findByPhaseId(phaseId: string): Promise<Plan[]>;
+
+  /**
+   * Update a plan.
+   * Throws if plan not found.
+   * Updates updatedAt timestamp automatically.
+   */
+  update(id: string, data: UpdatePlanData): Promise<Plan>;
+
+  /**
+   * Delete a plan.
+   * Throws if plan not found.
+   * Cascades to child tasks via FK constraints.
+   */
+  delete(id: string): Promise<void>;
+}
diff --git a/src/db/repositories/task-repository.ts b/src/db/repositories/task-repository.ts
new file mode 100644
index 0000000..1ae8e72
--- /dev/null
+++ b/src/db/repositories/task-repository.ts
@@ -0,0 +1,61 @@
+/**
+ * Task Repository Port Interface
+ *
+ * Port for Task aggregate operations.
+ * Implementations (Drizzle, etc.) are adapters.
+ */
+
+import type { Task, NewTask } from '../schema.js';
+
+/**
+ * Data for creating a new task.
+ * Omits system-managed fields (id, createdAt, updatedAt).
+ */
+export type CreateTaskData = Omit<NewTask, 'id' | 'createdAt' | 'updatedAt'>;
+
+/**
+ * Data for updating a task.
+ * Partial of creation data - all fields optional.
+ */
+export type UpdateTaskData = Partial<CreateTaskData>;
+
+/**
+ * Task Repository Port
+ *
+ * Defines operations for the Task aggregate.
+ * Only knows about tasks - no knowledge of parent entities.
+ */
+export interface TaskRepository {
+  /**
+   * Create a new task.
+   * Generates id and sets timestamps automatically.
+   * Foreign key to plan enforced by database.
+   */
+  create(data: CreateTaskData): Promise<Task>;
+
+  /**
+   * Find a task by its ID.
+   * Returns null if not found.
+   */
+  findById(id: string): Promise<Task | null>;
+
+  /**
+   * Find all tasks for a plan.
+   * Returns tasks ordered by order field.
+   * Returns empty array if none exist.
+   */
+  findByPlanId(planId: string): Promise<Task[]>;
+
+  /**
+   * Update a task.
+   * Throws if task not found.
+   * Updates updatedAt timestamp automatically.
+   */
+  update(id: string, data: UpdateTaskData): Promise<Task>;
+
+  /**
+   * Delete a task.
+   * Throws if task not found.
+   */
+  delete(id: string): Promise<void>;
+}