diff --git a/pyproject.toml b/pyproject.toml
index 4342753..038db48 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -7,12 +7,15 @@ name = "employee-manager"
 version = "1.0.0"
 description = "Application to manage the employees schedule."
 requires-python = ">=3.10"
-
-[project.optional-dependencies]
-menu = ["textual"]
+dependencies = [
+    "fastapi>=0.118",
+    "psycopg[binary]>=3.2",
+    "python-dotenv>=1.0",
+    "uvicorn[standard]>=0.37",
+]
 
 [project.scripts]
-scheduler = "scheduler.menu:main"
+scheduler = "scheduler.__main__:main"
 
 [tool.setuptools.packages.find]
 where=["src"]
diff --git a/src/scheduler/__init__.py b/src/scheduler/__init__.py
index e69de29..e3f54df 100644
--- a/src/scheduler/__init__.py
+++ b/src/scheduler/__init__.py
@@ -0,0 +1,3 @@
+__version__ = "1.0.0"
+
+__all__ = ["__version__"]
diff --git a/src/scheduler/__main__.py b/src/scheduler/__main__.py
index e69de29..23d4a42 100644
--- a/src/scheduler/__main__.py
+++ b/src/scheduler/__main__.py
@@ -0,0 +1,13 @@
+import os
+
+import uvicorn
+
+
+def main():
+    host = os.environ.get("APP_HOST", "127.0.0.1")
+    port = int(os.environ.get("APP_PORT", "5006"))
+    uvicorn.run("scheduler.main:app", host=host, port=port)
+
+
+if __name__ == "__main__":
+    main()
diff --git a/src/scheduler/api/__init__.py b/src/scheduler/api/__init__.py
new file mode 100644
index 0000000..f380ee1
--- /dev/null
+++ b/src/scheduler/api/__init__.py
@@ -0,0 +1,8 @@
+from . import company_routes, employee_routes, health_routes, schedule_routes
+
+__all__ = [
+    "company_routes",
+    "employee_routes",
+    "health_routes",
+    "schedule_routes",
+]
diff --git a/src/scheduler/api/company_routes.py b/src/scheduler/api/company_routes.py
new file mode 100644
index 0000000..6abc51b
--- /dev/null
+++ b/src/scheduler/api/company_routes.py
@@ -0,0 +1,35 @@
+from typing import Annotated
+
+from fastapi import APIRouter, Depends, HTTPException
+
+from scheduler.api.dependencies import get_company_service
+from scheduler.core.schemas.company import Company, CreateCompanyRequest
+from scheduler.core.services.company_service import CompanyService
+
+router = APIRouter(prefix="/companies", tags=["companies"])
+
+
+@router.get("", response_model=list[Company])
+def list_companies(service: Annotated[CompanyService, Depends(get_company_service)]):
+    return service.list_companies()
+
+
+@router.post("", response_model=Company)
+def create_company(payload: CreateCompanyRequest, service: Annotated[CompanyService, Depends(get_company_service)]):
+    return service.create_company(payload.name)
+
+
+@router.get("/{id}", response_model=Company)
+def get_company(id: int, service: Annotated[CompanyService, Depends(get_company_service)]):
+    company = service.get_company(id)
+    if company is None:
+        raise HTTPException(status_code=404, detail="Company not found")
+    return company
+
+
+@router.delete("/{id}", response_model=Company)
+def delete_company(id: int, service: Annotated[CompanyService, Depends(get_company_service)]):
+    company = service.delete_company(id)
+    if company is None:
+        raise HTTPException(status_code=404, detail="Company not found")
+    return company
diff --git a/src/scheduler/api/dependencies.py b/src/scheduler/api/dependencies.py
new file mode 100644
index 0000000..04ea107
--- /dev/null
+++ b/src/scheduler/api/dependencies.py
@@ -0,0 +1,50 @@
+from collections.abc import Generator
+
+from dotenv import load_dotenv
+
+from scheduler.core.services.company_service import CompanyService
+from scheduler.core.services.employee_service import EmployeeService
+from scheduler.core.services.schedule_service import ScheduleService
+from scheduler.database import CompanyRepository, Database, EmployeeRepository, ScheduleRepository
+
+
+
+def get_database() -> Database:
+    load_dotenv()
+    return Database()
+
+
+def get_db() -> Generator:
+    connection = get_database().get_connection()
+    try:
+        yield connection
+    finally:
+        connection.close()
+
+
+def get_company_service() -> Generator:
+    connection = get_database().get_connection()
+    try:
+        yield CompanyService(CompanyRepository(connection))
+    finally:
+        connection.close()
+
+
+def get_employee_service() -> Generator:
+    connection = get_database().get_connection()
+    try:
+        yield EmployeeService(EmployeeRepository(connection), CompanyRepository(connection))
+    finally:
+        connection.close()
+
+
+def get_schedule_service() -> Generator:
+    connection = get_database().get_connection()
+    try:
+        yield ScheduleService(
+            ScheduleRepository(connection),
+            EmployeeRepository(connection),
+            CompanyRepository(connection),
+        )
+    finally:
+        connection.close()
diff --git a/src/scheduler/api/employee_routes.py b/src/scheduler/api/employee_routes.py
new file mode 100644
index 0000000..6917967
--- /dev/null
+++ b/src/scheduler/api/employee_routes.py
@@ -0,0 +1,109 @@
+from typing import Annotated
+
+from fastapi import APIRouter, Depends, HTTPException
+
+from scheduler.api.dependencies import get_employee_service
+from scheduler.core.schemas.company import CompanyUser
+from scheduler.core.schemas.employee import (
+    CreateEmployeeRequest,
+    EmployeeNamesResponse,
+    EmployeeResponse,
+    RegisterPreferenceRequest,
+    UpdateEmployeeRequest,
+    WeeklyPreferenceRequest,
+)
+from scheduler.core.services.employee_service import EmployeeService
+
+router = APIRouter(tags=["employees"])
+
+
+@router.get("/employees", response_model=list[EmployeeResponse])
+def list_employees(service: Annotated[EmployeeService, Depends(get_employee_service)]):
+    return service.list_employees()
+
+
+@router.post("/employees", response_model=EmployeeResponse)
+def create_employee(payload: CreateEmployeeRequest, service: Annotated[EmployeeService, Depends(get_employee_service)]):
+    employee = service.create_employee(payload.company_id, payload.name, payload.last_name, payload.preference)
+    if employee is None:
+        raise HTTPException(status_code=404, detail="Company not found")
+    return employee
+
+
+@router.put("/employees/{id}", response_model=EmployeeResponse)
+def update_employee(
+    id: int,
+    payload: UpdateEmployeeRequest,
+    service: Annotated[EmployeeService, Depends(get_employee_service)],
+):
+    employee = service.update_employee(id, payload.name, payload.last_name, payload.preference, payload.company_id)
+    if employee is None:
+        raise HTTPException(status_code=404, detail="Employee or company not found")
+    return employee
+
+
+@router.patch("/employees/{id}", response_model=EmployeeResponse)
+def patch_employee(
+    id: int,
+    payload: UpdateEmployeeRequest,
+    service: Annotated[EmployeeService, Depends(get_employee_service)],
+):
+    employee = service.update_employee(id, payload.name, payload.last_name, payload.preference, payload.company_id)
+    if employee is None:
+        raise HTTPException(status_code=404, detail="Employee or company not found")
+    return employee
+
+
+@router.delete("/employees/{id}", response_model=EmployeeResponse)
+def delete_employee(id: int, service: Annotated[EmployeeService, Depends(get_employee_service)]):
+    employee = service.delete_employee(id)
+    if employee is None:
+        raise HTTPException(status_code=404, detail="Employee not found")
+    return employee
+
+
+@router.put("/employees/{id}/preference", response_model=EmployeeResponse)
+def register_employee_preference(
+    id: int,
+    payload: RegisterPreferenceRequest,
+    service: Annotated[EmployeeService, Depends(get_employee_service)],
+):
+    employee = service.update_preference(id, payload.preference)
+    if employee is None:
+        raise HTTPException(status_code=404, detail="Employee not found")
+    return employee
+
+
+@router.put("/employees/{id}/weekly-preferences", response_model=EmployeeResponse)
+def register_weekly_employee_preferences(
+    id: int,
+    payload: WeeklyPreferenceRequest,
+    service: Annotated[EmployeeService, Depends(get_employee_service)],
+):
+    employee = service.save_weekly_preferences(id, payload.preferences)
+    if employee is None:
+        raise HTTPException(status_code=404, detail="Employee not found")
+    return employee
+
+
+@router.post("/companies/{company_id}/employees/{employee_id}", response_model=CompanyUser)
+def assign_employee_to_company(
+    company_id: int,
+    employee_id: int,
+    service: Annotated[EmployeeService, Depends(get_employee_service)],
+):
+    company_user = service.assign_to_company(company_id, employee_id)
+    if company_user is None:
+        raise HTTPException(status_code=404, detail="Company or employee not found")
+    return company_user
+
+
+@router.get("/companies/{company_name}/employees/names", response_model=EmployeeNamesResponse)
+def get_employee_names_by_company(
+    company_name: str,
+    service: Annotated[EmployeeService, Depends(get_employee_service)],
+):
+    employees = service.get_names_by_company_name(company_name)
+    if employees is None:
+        raise HTTPException(status_code=404, detail="Company not found")
+    return {"employees": employees}
diff --git a/src/scheduler/api/health_routes.py b/src/scheduler/api/health_routes.py
new file mode 100644
index 0000000..a38a2a4
--- /dev/null
+++ b/src/scheduler/api/health_routes.py
@@ -0,0 +1,10 @@
+from fastapi import APIRouter
+
+from scheduler.core.schemas.health import HealthResponse
+
+router = APIRouter(tags=["health"])
+
+
+@router.get("/health", response_model=HealthResponse)
+def health_check():
+    return {"status": "ok"}
diff --git a/src/scheduler/api/schedule_routes.py b/src/scheduler/api/schedule_routes.py
new file mode 100644
index 0000000..86ea4f0
--- /dev/null
+++ b/src/scheduler/api/schedule_routes.py
@@ -0,0 +1,68 @@
+from typing import Annotated
+
+from fastapi import APIRouter, Depends, HTTPException
+
+from scheduler.api.dependencies import get_schedule_service
+from scheduler.core.schemas.schedule import (
+    ClockInRequest,
+    ClockOutRequest,
+    CreateScheduleRequest,
+    GenerateWeeklyScheduleRequest,
+    ScheduleResponse,
+    WeeklyScheduleResponse,
+)
+from scheduler.core.services.schedule_service import ScheduleService
+
+router = APIRouter(tags=["schedules"])
+
+
+@router.post("/schedules", response_model=ScheduleResponse)
+def create_schedule(payload: CreateScheduleRequest, service: Annotated[ScheduleService, Depends(get_schedule_service)]):
+    schedule = service.create_schedule(payload.user_id, payload.enter_time, payload.day_of_week, payload.out_time)
+    if schedule is None:
+        raise HTTPException(status_code=404, detail="Employee not found")
+    return schedule
+
+
+@router.post("/employees/{id}/clock-in", response_model=ScheduleResponse)
+def clock_in(
+    id: int,
+    payload: ClockInRequest,
+    service: Annotated[ScheduleService, Depends(get_schedule_service)],
+):
+    schedule = service.clock_in(
+        id,
+        day_of_week=payload.day_of_week,
+        enter_time=payload.enter_time,
+    )
+    if schedule is None:
+        raise HTTPException(status_code=404, detail="Employee not found")
+    return schedule
+
+
+@router.put("/employees/{id}/clock-out", response_model=ScheduleResponse)
+def clock_out(
+    id: int,
+    payload: ClockOutRequest,
+    service: Annotated[ScheduleService, Depends(get_schedule_service)],
+):
+    schedule = service.clock_out(id, payload.day_of_week, payload.out_time)
+    if schedule is None:
+        raise HTTPException(status_code=404, detail="Schedule not found")
+    return schedule
+
+
+@router.get("/schedules/weekly", response_model=WeeklyScheduleResponse)
+def get_weekly_schedule(service: Annotated[ScheduleService, Depends(get_schedule_service)]):
+    return service.get_weekly_schedule()
+
+
+@router.post("/schedules/weekly/generate", response_model=WeeklyScheduleResponse)
+def generate_weekly_schedule(
+    payload: GenerateWeeklyScheduleRequest,
+    service: Annotated[ScheduleService, Depends(get_schedule_service)],
+):
+    schedule = service.generate_weekly_schedule(payload.company_id)
+    if schedule is None:
+        raise HTTPException(status_code=404, detail="Company not found")
+    return schedule
diff --git a/src/scheduler/app.py b/src/scheduler/app.py
new file mode 100644
index 0000000..28f2e2d
--- /dev/null
+++ b/src/scheduler/app.py
@@ -0,0 +1,46 @@
+from contextlib import asynccontextmanager
+
+from dotenv import load_dotenv
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+
+from scheduler.api import company_routes, employee_routes, health_routes, schedule_routes
+from scheduler.database import Database
+
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    Database().initialize_schema()
+    yield
+
+
+def create_app() -> FastAPI:
+    load_dotenv()
+
+    app = FastAPI(
+        title="manager_employees_python",
+        lifespan=lifespan,
+        openapi_url="/api-docs/openapi.json",
+        docs_url="/swagger-ui/",
+    )
+    app.add_middleware(
+        CORSMiddleware,
+        allow_origins=["*"],
+        allow_credentials=True,
+        allow_methods=["*"],
+        allow_headers=["*"],
+    )
+
+    app.include_router(health_routes.router)
+    app.include_router(company_routes.router)
+    app.include_router(employee_routes.router)
+    app.include_router(schedule_routes.router)
+
+    @app.get("/api-docs/openai.json", include_in_schema=False)
+    def openai_json_alias():
+        return app.openapi()
+
+    return app
+
+
+app = create_app()
diff --git a/src/scheduler/tui/__init__.py b/src/scheduler/core/__init__.py
similarity index 100%
rename from src/scheduler/tui/__init__.py
rename to src/scheduler/core/__init__.py
diff --git a/src/scheduler/core/enums/__init__.py b/src/scheduler/core/enums/__init__.py
new file mode 100644
index 0000000..ef53d3e
--- /dev/null
+++ b/src/scheduler/core/enums/__init__.py
@@ -0,0 +1,4 @@
+from scheduler.core.enums.day_of_week import DayOfWeek
+from scheduler.core.enums.work_time import WorkTime
+
+__all__ = ["DayOfWeek", "WorkTime"]
diff --git a/src/scheduler/core/enums/day_of_week.py b/src/scheduler/core/enums/day_of_week.py
new file mode 100644
index 0000000..2f6f190
--- /dev/null
+++ b/src/scheduler/core/enums/day_of_week.py
@@ -0,0 +1,11 @@
+from enum import Enum
+
+
+class DayOfWeek(str, Enum):
+    SUNDAY = "sunday"
+    MONDAY = "monday"
+    TUESDAY = "tuesday"
+    WEDNESDAY = "wednesday"
+    THURSDAY = "thursday"
+    FRIDAY = "friday"
+    SATURDAY = "saturday"
diff --git a/src/scheduler/core/enums/work_time.py b/src/scheduler/core/enums/work_time.py
new file mode 100644
index 0000000..b25d715
--- /dev/null
+++ b/src/scheduler/core/enums/work_time.py
@@ -0,0 +1,7 @@
+from enum import Enum
+
+
+class WorkTime(str, Enum):
+    MORNING = "morning"
+    AFTERNOON = "afternoon"
+    EVENING = "evening"
diff --git a/src/scheduler/tui/screens/__init__.py b/src/scheduler/core/schemas/__init__.py
similarity index 100%
rename from src/scheduler/tui/screens/__init__.py
rename to src/scheduler/core/schemas/__init__.py
diff --git a/src/scheduler/core/schemas/company.py b/src/scheduler/core/schemas/company.py
new file mode 100644
index 0000000..ff6b091
--- /dev/null
+++ b/src/scheduler/core/schemas/company.py
@@ -0,0 +1,22 @@
+from datetime import datetime
+
+from pydantic import BaseModel
+
+
+class CreateCompanyRequest(BaseModel):
+    name: str
+
+
+class Company(BaseModel):
+    id: int
+    name: str
+    date_created: datetime
+    date_updated: datetime
+
+
+class CompanyUser(BaseModel):
+    id: int
+    user_id: int
+    company_id: int
+    date_created: datetime
+    date_updated: datetime
diff --git a/src/scheduler/core/schemas/employee.py b/src/scheduler/core/schemas/employee.py
new file mode 100644
index 0000000..d61ae6d
--- /dev/null
+++ b/src/scheduler/core/schemas/employee.py
@@ -0,0 +1,44 @@
+from pydantic import BaseModel
+
+from scheduler.core.enums import DayOfWeek, WorkTime
+
+
+class CreateEmployeeRequest(BaseModel):
+    company_id: int
+    name: str
+    last_name: str
+    preference: WorkTime
+
+
+class RegisterPreferenceRequest(BaseModel):
+    preference: WorkTime
+
+
+class DayPreferenceRequest(BaseModel):
+    day_of_week: DayOfWeek
+    first: WorkTime
+    second: WorkTime
+    third: WorkTime
+
+
+class WeeklyPreferenceRequest(BaseModel):
+    preferences: list[DayPreferenceRequest]
+
+
+class EmployeeNamesResponse(BaseModel):
+    employees: list[str]
+
+
+class UpdateEmployeeRequest(BaseModel):
+    company_id: int | None = None
+    name: str
+    last_name: str
+    preference: WorkTime
+
+
+class EmployeeResponse(BaseModel):
+    id: int
+    company_id: int
+    name: str
+    last_name: str
+    preference: WorkTime
diff --git a/src/scheduler/core/schemas/health.py b/src/scheduler/core/schemas/health.py
new file mode 100644
index 0000000..a3ef630
--- /dev/null
+++ b/src/scheduler/core/schemas/health.py
@@ -0,0 +1,5 @@
+from pydantic import BaseModel
+
+
+class HealthResponse(BaseModel):
+    status: str
diff --git a/src/scheduler/core/schemas/schedule.py b/src/scheduler/core/schemas/schedule.py
new file mode 100644
index 0000000..686b421
--- /dev/null
+++ b/src/scheduler/core/schemas/schedule.py
@@ -0,0 +1,38 @@
+from datetime import datetime
+
+from pydantic import BaseModel
+
+from scheduler.core.enums import DayOfWeek
+
+
+class CreateScheduleRequest(BaseModel):
+    user_id: int
+    enter_time: datetime
+    day_of_week: DayOfWeek
+    out_time: datetime
+
+
+class ClockInRequest(BaseModel):
+    day_of_week: DayOfWeek
+    enter_time: datetime
+
+
+class ClockOutRequest(BaseModel):
+    day_of_week: DayOfWeek
+    out_time: datetime
+
+
+class GenerateWeeklyScheduleRequest(BaseModel):
+    company_id: int
+
+
+class ScheduleResponse(BaseModel):
+    id: int
+    user_id: int
+    enter_time: datetime
+    day_of_week: DayOfWeek
+    out_time: datetime | None = None
+
+
+class WeeklyScheduleResponse(BaseModel):
+    schedules: list[ScheduleResponse]
diff --git a/src/scheduler/database/employees.json b/src/scheduler/core/services/__init__.py
similarity index 100%
rename from src/scheduler/database/employees.json
rename to src/scheduler/core/services/__init__.py
diff --git a/src/scheduler/core/services/company_service.py b/src/scheduler/core/services/company_service.py
new file mode 100644
index 0000000..e32e2d4
--- /dev/null
+++ b/src/scheduler/core/services/company_service.py
@@ -0,0 +1,18 @@
+from scheduler.database.company_repository import CompanyRepository
+
+
+class CompanyService:
+    def __init__(self, repository: CompanyRepository):
+        self.repository = repository
+
+    def list_companies(self):
+        return self.repository.list()
+
+    def create_company(self, name: str):
+        return self.repository.create(name)
+
+    def get_company(self, company_id: int):
+        return self.repository.get(company_id)
+
+    def delete_company(self, company_id: int):
+        return self.repository.delete(company_id)
diff --git a/src/scheduler/core/services/employee_service.py b/src/scheduler/core/services/employee_service.py
new file mode 100644
index 0000000..603b3b6
--- /dev/null
+++ b/src/scheduler/core/services/employee_service.py
@@ -0,0 +1,57 @@
+from scheduler.database.company_repository import CompanyRepository
+from scheduler.database.employee_repository import EmployeeRepository
+
+
+class EmployeeService:
+    def __init__(self, employee_repository: EmployeeRepository, company_repository: CompanyRepository):
+        self.employee_repository = employee_repository
+        self.company_repository = company_repository
+
+    def list_employees(self):
+        return self.employee_repository.list()
+
+    def create_employee(self, company_id: int, name: str, last_name: str, preference: str):
+        if self.company_repository.get(company_id) is None:
+            return None
+        return self.employee_repository.create(company_id, name, last_name, preference)
+
+    def delete_employee(self, employee_id: int):
+        return self.employee_repository.delete(employee_id)
+
+    def update_preference(self, employee_id: int, preference: str):
+        return self.employee_repository.update_preference(employee_id, preference)
+
+    def update_employee(
+        self,
+        employee_id: int,
+        name: str,
+        last_name: str,
+        preference: str,
+        company_id: int | None,
+    ):
+        if self.employee_repository.get(employee_id) is None:
+            return None
+        if company_id is not None and self.company_repository.get(company_id) is None:
+            return None
+        updated = self.employee_repository.update(employee_id, name, last_name, preference)
+        if company_id is not None:
+            updated = self.employee_repository.update_company(employee_id, company_id)
+        return updated
+
+    def assign_to_company(self, company_id: int, employee_id: int):
+        if self.company_repository.get(company_id) is None:
+            return None
+        if self.employee_repository.get(employee_id) is None:
+            return None
+        return self.employee_repository.assign_to_company(company_id, employee_id)
+
+    def get_names_by_company_name(self, company_name: str):
+        company = self.company_repository.get_by_name(company_name)
+        if company is None:
+            return None
+        return self.employee_repository.get_names_by_company(company["id"])
+
+    def save_weekly_preferences(self, employee_id: int, preferences: list):
+        if self.employee_repository.get(employee_id) is None:
+            return None
+        return self.employee_repository.save_weekly_preferences(employee_id, preferences)
diff --git a/src/scheduler/core/services/schedule_service.py b/src/scheduler/core/services/schedule_service.py
new file mode 100644
index 0000000..3e44ba4
--- /dev/null
+++ b/src/scheduler/core/services/schedule_service.py
@@ -0,0 +1,46 @@
+from datetime import datetime
+
+from scheduler.database.company_repository import CompanyRepository
+from scheduler.database.employee_repository import EmployeeRepository
+from scheduler.database.schedule_repository import ScheduleRepository
+
+
+class ScheduleService:
+    def __init__(
+        self,
+        schedule_repository: ScheduleRepository,
+        employee_repository: EmployeeRepository,
+        company_repository: CompanyRepository,
+    ):
+        self.schedule_repository = schedule_repository
+        self.employee_repository = employee_repository
+        self.company_repository = company_repository
+
+    def create_schedule(self, user_id: int, enter_time: datetime, day_of_week: str, out_time: datetime):
+        if self.employee_repository.get(user_id) is None:
+            return None
+        return self.schedule_repository.create(user_id, enter_time, day_of_week, out_time)
+
+    def clock_in(
+        self,
+        user_id: int,
+        day_of_week: str,
+        enter_time: datetime,
+    ):
+        employee = self.employee_repository.get(user_id)
+        if employee is None:
+            return None
+        return self.schedule_repository.create(user_id, enter_time, day_of_week, None)
+
+    def clock_out(self, user_id: int, day_of_week: str, out_time: datetime):
+        if self.employee_repository.get(user_id) is None:
+            return None
+        return self.schedule_repository.update_clock_out(user_id, day_of_week, out_time)
+
+    def get_weekly_schedule(self, company_id: int | None = None):
+        return {"schedules": self.schedule_repository.list_weekly(company_id)}
+
+    def generate_weekly_schedule(self, company_id: int):
+        if self.company_repository.get(company_id) is None:
+            return None
+        return self.get_weekly_schedule(company_id)
diff --git a/src/scheduler/database/__init__.py b/src/scheduler/database/__init__.py
index e69de29..c8f6858 100644
--- a/src/scheduler/database/__init__.py
+++ b/src/scheduler/database/__init__.py
@@ -0,0 +1,6 @@
+from scheduler.database.company_repository import CompanyRepository
+from scheduler.database.database import Database
+from scheduler.database.employee_repository import EmployeeRepository
+from scheduler.database.schedule_repository import ScheduleRepository
+
+__all__ = ["CompanyRepository", "Database", "EmployeeRepository", "ScheduleRepository"]
diff --git a/src/scheduler/database/company_repository.py b/src/scheduler/database/company_repository.py
new file mode 100644
index 0000000..c07451d
--- /dev/null
+++ b/src/scheduler/database/company_repository.py
@@ -0,0 +1,66 @@
+class CompanyRepository:
+    def __init__(self, connection):
+        self.connection = connection
+
+    def list(self):
+        with self.connection.cursor() as cursor:
+            cursor.execute(
+                """
+                SELECT id, name, date_created, date_updated
+                FROM companies
+                ORDER BY id
+                """
+            )
+            return cursor.fetchall()
+
+    def create(self, name: str):
+        with self.connection.cursor() as cursor:
+            cursor.execute(
+                """
+                INSERT INTO companies (name)
+                VALUES (%s)
+                RETURNING id, name, date_created, date_updated
+                """,
+                (name,),
+            )
+            company = cursor.fetchone()
+        self.connection.commit()
+        return company
+
+    def get(self, company_id: int):
+        with self.connection.cursor() as cursor:
+            cursor.execute(
+                """
+                SELECT id, name, date_created, date_updated
+                FROM companies
+                WHERE id = %s
+                """,
+                (company_id,),
+            )
+            return cursor.fetchone()
+
+    def get_by_name(self, name: str):
+        with self.connection.cursor() as cursor:
+            cursor.execute(
+                """
+                SELECT id, name, date_created, date_updated
+                FROM companies
+                WHERE name = %s
+                """,
+                (name,),
+            )
+            return cursor.fetchone()
+
+    def delete(self, company_id: int):
+        with self.connection.cursor() as cursor:
+            cursor.execute(
+                """
+                DELETE FROM companies
+                WHERE id = %s
+                RETURNING id, name, date_created, date_updated
+                """,
+                (company_id,),
+            )
+            company = cursor.fetchone()
+        self.connection.commit()
+        return company
diff --git a/src/scheduler/database/database.py b/src/scheduler/database/database.py
new file mode 100644
index 0000000..2623d49
--- /dev/null
+++ b/src/scheduler/database/database.py
@@ -0,0 +1,105 @@
+import os
+
+import psycopg
+from psycopg.rows import dict_row
+
+
+DEFAULT_DATABASE_URL = "postgres://carlos:password@localhost/rust_manager_employees"
+
+
+class Database:
+    def __init__(self, database_url: str | None = None):
+        self.database_url = database_url or os.environ.get("DATABASE_URL", DEFAULT_DATABASE_URL)
+
+    def get_connection(self):
+        return psycopg.connect(self.database_url, row_factory=dict_row)
+
+    def initialize_schema(self):
+        with self.get_connection() as connection:
+            with connection.cursor() as cursor:
+                cursor.execute(
+                    """
+                    DO $$
+                    BEGIN
+                        CREATE TYPE work_time AS ENUM ('morning', 'afternoon', 'evening');
+                    EXCEPTION WHEN duplicate_object THEN NULL;
+                    END $$;
+                    """
+                )
+                cursor.execute("ALTER TYPE work_time ADD VALUE IF NOT EXISTS 'afternoon';")
+                cursor.execute(
+                    """
+                    DO $$
+                    BEGIN
+                        CREATE TYPE day_of_week AS ENUM (
+                            'sunday', 'monday', 'tuesday', 'wednesday',
+                            'thursday', 'friday', 'saturday'
+                        );
+                    EXCEPTION WHEN duplicate_object THEN NULL;
+                    END $$;
+                    """
+                )
+                cursor.execute(
+                    """
+                    CREATE TABLE IF NOT EXISTS companies (
+                        id SERIAL PRIMARY KEY,
+                        name TEXT NOT NULL UNIQUE,
+                        date_created TIMESTAMP NOT NULL DEFAULT NOW(),
+                        date_updated TIMESTAMP NOT NULL DEFAULT NOW()
+                    );
+                    """
+                )
+                cursor.execute(
+                    """
+                    CREATE TABLE IF NOT EXISTS users (
+                        id SERIAL PRIMARY KEY,
+                        name TEXT NOT NULL,
+                        last_name TEXT NOT NULL,
+                        preference work_time NOT NULL,
+                        date_created TIMESTAMP NOT NULL DEFAULT NOW(),
+                        date_updated TIMESTAMP NOT NULL DEFAULT NOW()
+                    );
+                    """
+                )
+                cursor.execute(
+                    """
+                    CREATE TABLE IF NOT EXISTS company_users (
+                        id SERIAL PRIMARY KEY,
+                        user_id INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+                        company_id INTEGER NOT NULL REFERENCES companies(id) ON DELETE CASCADE,
+                        date_created TIMESTAMP NOT NULL DEFAULT NOW(),
+                        date_updated TIMESTAMP NOT NULL DEFAULT NOW(),
+                        UNIQUE (user_id, company_id)
+                    );
+                    """
+                )
+                cursor.execute(
+                    """
+                    CREATE TABLE IF NOT EXISTS schedules (
+                        id SERIAL PRIMARY KEY,
+                        user_id INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+                        enter_time TIMESTAMP NOT NULL,
+                        day_of_week day_of_week NOT NULL,
+                        out_time TIMESTAMP,
+                        date_created TIMESTAMP NOT NULL DEFAULT NOW(),
+                        date_updated TIMESTAMP NOT NULL DEFAULT NOW()
+                    );
+                    """
+                )
+                cursor.execute("ALTER TABLE schedules ALTER COLUMN out_time DROP NOT NULL;")
+                cursor.execute(
+                    """
+                    CREATE TABLE IF NOT EXISTS weekly_preferences (
+                        id SERIAL PRIMARY KEY,
+                        user_id INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+                        day_of_week day_of_week NOT NULL,
+                        first work_time NOT NULL,
+                        second work_time NOT NULL,
+                        third work_time NOT NULL,
+                        date_created TIMESTAMP NOT NULL DEFAULT NOW(),
+                        date_updated TIMESTAMP NOT NULL DEFAULT NOW(),
+                        UNIQUE (user_id, day_of_week)
+                    );
+                    """
+                )
+            connection.commit()
diff --git a/src/scheduler/database/employee_repository.py b/src/scheduler/database/employee_repository.py
new file mode 100644
index 0000000..3096039
--- /dev/null
+++ b/src/scheduler/database/employee_repository.py
@@ -0,0 +1,167 @@
+class EmployeeRepository:
+    def __init__(self, connection):
+        self.connection = connection
+
+    def list(self):
+        with self.connection.cursor() as cursor:
+            cursor.execute(
+                """
+                SELECT users.id, company_users.company_id, users.name, users.last_name, users.preference
+                FROM users
+                INNER JOIN company_users ON company_users.user_id = users.id
+                ORDER BY users.id
+                """
+            )
+            return cursor.fetchall()
+
+    def create(self, company_id: int, name: str, last_name: str, preference: str):
+        with self.connection.cursor() as cursor:
+            cursor.execute(
+                """
+                INSERT INTO users (name, last_name, preference)
+                VALUES (%s, %s, %s)
+                RETURNING id, name, last_name, preference
+                """,
+                (name, last_name, preference),
+            )
+            user = cursor.fetchone()
+            cursor.execute(
+                """
+                INSERT INTO company_users (user_id, company_id)
+                VALUES (%s, %s)
+                RETURNING company_id
+                """,
+                (user["id"], company_id),
+            )
+            company_user = cursor.fetchone()
+        self.connection.commit()
+        return {**user, "company_id": company_user["company_id"]}
+
+    def get(self, employee_id: int):
+        with self.connection.cursor() as cursor:
+            cursor.execute(
+                """
+                SELECT users.id, company_users.company_id, users.name, users.last_name, users.preference
+                FROM users
+                INNER JOIN company_users ON company_users.user_id = users.id
+                WHERE users.id = %s
+                """,
+                (employee_id,),
+            )
+            return cursor.fetchone()
+
+    def delete(self, employee_id: int):
+        employee = self.get(employee_id)
+        if employee is None:
+            return None
+        with self.connection.cursor() as cursor:
+            cursor.execute("DELETE FROM users WHERE id = %s", (employee_id,))
+        self.connection.commit()
+        return employee
+
+    def update_preference(self, employee_id: int, preference: str):
+        with self.connection.cursor() as cursor:
+            cursor.execute(
+                """
+                UPDATE users
+                SET preference = %s, date_updated = NOW()
+                WHERE id = %s
+                """,
+                (preference, employee_id),
+            )
+        self.connection.commit()
+        return self.get(employee_id)
+
+    def update(self, employee_id: int, name: str | None, last_name: str | None, preference: str | None):
+        updates: list[str] = []
+        params: list[object] = []
+        if name is not None:
+            updates.append("name = %s")
+            params.append(name)
+        if last_name is not None:
+            updates.append("last_name = %s")
+            params.append(last_name)
+        if preference is not None:
+            updates.append("preference = %s")
+            params.append(preference)
+        if updates:
+            updates.append("date_updated = NOW()")
+            params.append(employee_id)
+            with self.connection.cursor() as cursor:
+                cursor.execute(
+                    f"""
+                    UPDATE users
+                    SET {", ".join(updates)}
+                    WHERE id = %s
+                    """,
+                    tuple(params),
+                )
+            self.connection.commit()
+        return self.get(employee_id)
+
+    def update_company(self, employee_id: int, company_id: int):
+        with self.connection.cursor() as cursor:
+            cursor.execute("DELETE FROM company_users WHERE user_id = %s", (employee_id,))
+            cursor.execute(
+                """
+                INSERT INTO company_users (user_id, company_id)
+                VALUES (%s, %s)
+                ON CONFLICT (user_id, company_id) DO UPDATE SET date_updated = NOW()
+                """,
+                (employee_id, company_id),
+            )
+        self.connection.commit()
+        return self.get(employee_id)
+
+    def assign_to_company(self, company_id: int, employee_id: int):
+        with self.connection.cursor() as cursor:
+            cursor.execute(
+                """
+                INSERT INTO company_users (user_id, company_id)
+                VALUES (%s, %s)
+                ON CONFLICT (user_id, company_id) DO UPDATE SET date_updated = NOW()
+                RETURNING id, user_id, company_id, date_created, date_updated
+                """,
+                (employee_id, company_id),
+            )
+            company_user = cursor.fetchone()
+        self.connection.commit()
+        return company_user
+
+    def get_names_by_company(self, company_id: int):
+        with self.connection.cursor() as cursor:
+            cursor.execute(
+                """
+                SELECT users.name, users.last_name
+                FROM users
+                INNER JOIN company_users ON company_users.user_id = users.id
+                WHERE company_users.company_id = %s
+                ORDER BY users.name, users.last_name
+                """,
+                (company_id,),
+            )
+            return [f"{row['name']} {row['last_name']}" for row in cursor.fetchall()]
+
+    def save_weekly_preferences(self, employee_id: int, preferences: list):
+        with self.connection.cursor() as cursor:
+            for preference in preferences:
+                cursor.execute(
+                    """
+                    INSERT INTO weekly_preferences (user_id, day_of_week, first, second, third)
+                    VALUES (%s, %s, %s, %s, %s)
+                    ON CONFLICT (user_id, day_of_week) DO UPDATE SET
+                        first = EXCLUDED.first,
+                        second = EXCLUDED.second,
+                        third = EXCLUDED.third,
+                        date_updated = NOW()
+                    """,
+                    (
+                        employee_id,
+                        preference.day_of_week,
+                        preference.first,
+                        preference.second,
+                        preference.third,
+                    ),
+                )
+        self.connection.commit()
+        return self.get(employee_id)
diff --git a/src/scheduler/database/schedule_repository.py b/src/scheduler/database/schedule_repository.py
new file mode 100644
index 0000000..56324cf
--- /dev/null
+++ b/src/scheduler/database/schedule_repository.py
@@ -0,0 +1,61 @@
+from datetime import datetime
+
+
+class ScheduleRepository:
+    def __init__(self, connection):
+        self.connection = connection
+
+    def create(self, user_id: int, enter_time: datetime, day_of_week: str, out_time: datetime | None):
+        with self.connection.cursor() as cursor:
+            cursor.execute(
+                """
+                INSERT INTO schedules (user_id, enter_time, day_of_week, out_time)
+                VALUES (%s, %s, %s, %s)
+                RETURNING id, user_id, enter_time, day_of_week, out_time
+                """,
+                (user_id, enter_time, day_of_week, out_time),
+            )
+            schedule = cursor.fetchone()
+        self.connection.commit()
+        return schedule
+
+    def list_weekly(self, company_id: int | None = None):
+        params = ()
+        where = ""
+        if company_id is not None:
+            where = "WHERE company_users.company_id = %s"
+            params = (company_id,)
+        with self.connection.cursor() as cursor:
+            cursor.execute(
+                f"""
+                SELECT schedules.id, schedules.user_id, schedules.enter_time,
+                       schedules.day_of_week, schedules.out_time
+                FROM schedules
+                INNER JOIN company_users ON company_users.user_id = schedules.user_id
+                {where}
+                ORDER BY schedules.day_of_week, schedules.enter_time, schedules.id
+                """,
+                params,
+            )
+            return cursor.fetchall()
+
+    def update_clock_out(self, user_id: int, day_of_week: str, out_time: datetime):
+        with self.connection.cursor() as cursor:
+            cursor.execute(
+                """
+                UPDATE schedules
+                SET out_time = %s, date_updated = NOW()
+                WHERE id = (
+                    SELECT id
+                    FROM schedules
+                    WHERE user_id = %s AND day_of_week = %s
+                    ORDER BY date_created DESC
+                    LIMIT 1
+                )
+                RETURNING id, user_id, enter_time, day_of_week, out_time
+                """,
+                (out_time, user_id, day_of_week),
+            )
+            schedule = cursor.fetchone()
+        self.connection.commit()
+        return schedule
diff --git a/src/scheduler/database/storage.py b/src/scheduler/database/storage.py
index e69de29..378dc38 100644
--- a/src/scheduler/database/storage.py
+++ b/src/scheduler/database/storage.py
@@ -0,0 +1,93 @@
+from scheduler.database.company_repository import CompanyRepository
+from scheduler.database.database import Database
+from scheduler.database.employee_repository import EmployeeRepository
+from scheduler.database.schedule_repository import ScheduleRepository
+
+
+def get_connection():
+    return Database().get_connection()
+
+
+def initialize_schema(connection=None):
+    Database().initialize_schema()
+
+
+def add_company(connection, name):
+    return CompanyRepository(connection).create(name)
+
+
+def get_company_by_name(connection, name):
+    return CompanyRepository(connection).get_by_name(name)
+
+
+def remove_company(connection, company_id):
+    return CompanyRepository(connection).delete(company_id)
+
+
+def get_employee_names_by_company(connection, company_id):
+    return EmployeeRepository(connection).get_names_by_company(company_id)
+
+
+def add_user(connection, name, last_name, preference):
+    with connection.cursor() as cursor:
+        cursor.execute(
+            """
+            INSERT INTO users (name, last_name, preference)
+            VALUES (%s, %s, %s)
+            RETURNING id, name, last_name, preference, date_created, date_updated
+            """,
+            (name, last_name, preference),
+        )
+        user = cursor.fetchone()
+    connection.commit()
+    return user
+
+
+def update_user_preference(connection, user_id, preference):
+    return EmployeeRepository(connection).update_preference(user_id, preference)
+
+
+def add_company_user(connection, company_id, user_id):
+    return EmployeeRepository(connection).assign_to_company(company_id, user_id)
+
+
+def remove_user(connection, user_id):
+    return EmployeeRepository(connection).delete(user_id)
+
+
+def add_schedule(connection, user_id, enter_time, day_of_week, out_time):
+    return ScheduleRepository(connection).create(user_id, enter_time, day_of_week, out_time)
+
+
+def get_days_worked_by_user(connection, user_id):
+    with connection.cursor() as cursor:
+        cursor.execute(
+            """
+            SELECT DISTINCT day_of_week
+            FROM schedules
+            WHERE user_id = %s
+            ORDER BY day_of_week
+            """,
+            (user_id,),
+        )
+        return [row["day_of_week"] for row in cursor.fetchall()]
+
+
+def get_user_enter_time_by_day(connection, user_id, day_of_week):
+    with connection.cursor() as cursor:
+        cursor.execute(
+            """
+            SELECT enter_time
+            FROM schedules
+            WHERE user_id = %s AND day_of_week = %s
+            ORDER BY date_created DESC
+            LIMIT 1
+            """,
+            (user_id, day_of_week),
+        )
+        row = cursor.fetchone()
+        return None if row is None else row["enter_time"]
+
+
+def update_day_end_by_user_and_day(connection, user_id, day_of_week, out_time):
+    return ScheduleRepository(connection).update_clock_out(user_id, day_of_week, out_time)
diff --git a/src/scheduler/main.py b/src/scheduler/main.py
new file mode 100644
index 0000000..7ee44dd
--- /dev/null
+++ b/src/scheduler/main.py
@@ -0,0 +1,3 @@
+from scheduler.app import app, create_app
+
+__all__ = ["app", "create_app"]
diff --git a/src/scheduler/manager/__init__.py b/src/scheduler/manager/__init__.py
index e69de29..8fc5368 100644
--- a/src/scheduler/manager/__init__.py
+++ b/src/scheduler/manager/__init__.py
@@ -0,0 +1,3 @@
+from . import conflict, scheduler, validator
+
+__all__ = ["conflict", "scheduler", "validator"]
diff --git a/src/scheduler/manager/conflict.py b/src/scheduler/manager/conflict.py
index e69de29..d3d02d1 100644
--- a/src/scheduler/manager/conflict.py
+++ b/src/scheduler/manager/conflict.py
@@ -0,0 +1,32 @@
+# Conflict resolution guide.
+# Import validator functions before moving employees between shifts or days.
+
+
+def detect_preferred_shift_conflict(connection, user_id, day_of_week, preferred_shift):
+    # check if preferred shift is already full for selected day
+    # check if user already works that day
+    # check if user already worked five days this week
+    pass
+
+
+def resolve_conflict_same_day(connection, user_id, day_of_week):
+    # loop over other shifts on the same day
+    # choose the first shift where user can legally work
+    # assign only after validator confirms the schedule is valid
+    pass
+
+
+def resolve_conflict_next_day(connection, user_id, current_day):
+    # if same-day alternatives fail, move to next day
+    # loop through next-day shifts by preference priority
+    # assign only after validator confirms the schedule is valid
+    pass
+
+
+def resolve_missing_second_employee(connection, company_id, day_of_week, shift):
+    # find shifts with only one employee assigned
+    # loop over available employees in company
+    # skip employees who already work that day
+    # skip employees who already worked five days this week
+    # assign a valid extra employee to satisfy minimum coverage
+    pass
diff --git a/src/scheduler/manager/scheduler.py b/src/scheduler/manager/scheduler.py
index e69de29..77168e0 100644
--- a/src/scheduler/manager/scheduler.py
+++ b/src/scheduler/manager/scheduler.py
@@ -0,0 +1,52 @@
+# Schedule generation guide.
+# Import database.storage for queries and manager.validator/conflict for rules.
+
+
+def generate_weekly_schedule(connection, company_id):
+    # load all employees for selected company
+    # load employee preferences for all seven days
+    # loop through each day of the week
+    # loop through morning, afternoon, and evening shifts
+    # assign employees based on preferences first
+    # validate one-shift-per-day before each assignment
+    # validate five-days-per-week before each assignment
+    # ensure at least two employees per shift after assignments
+    # resolve conflicts by assigning another shift on same day or next day
+    # save final schedule rows to the schedules table
+    pass
+
+
+def assign_preferred_shift(connection, user_id, day_of_week, preferred_shift):
+    # validate employee can join selected shift
+    # call storage.add_schedule when assignment is valid
+    # return validation error if assignment is not valid
+    pass
+
+
+def fill_missing_shift_coverage(connection, company_id, day_of_week, shift):
+    # find company shift with fewer than two employees
+    # if only one employee is assigned, search for another valid employee
+    # randomly choose or rotate through employees who have not worked five days
+    # add the selected employee to the schedule
+    pass
+
+
+def register_clock_in(connection, user_id, day_of_week, enter_time):
+    # reject if user already worked the same day
+    # reject if user already worked five days this week
+    # save enter_time through storage.add_schedule or update an open schedule row
+    pass
+
+
+def register_clock_out(connection, user_id, day_of_week, out_time):
+    # call storage.update_day_end_by_user_and_day
+    # keep the existing schedule row and update out_time only
+    pass
+
+
+def print_final_schedule(connection, company_id):
+    # query final schedule with employee names
+    # group output by day and shift
+    # print employees assigned to each shift
+    # print warnings for shifts with fewer than two employees
+    pass
diff --git a/src/scheduler/manager/validator.py b/src/scheduler/manager/validator.py
index e69de29..905cf85 100644
--- a/src/scheduler/manager/validator.py
+++ b/src/scheduler/manager/validator.py
@@ -0,0 +1,38 @@
+# Validation guide for schedule rules.
+# Import scheduler.database.storage query functions before implementing these checks.
+
+
+def validate_user_has_not_worked_same_day(connection, user_id, day_of_week):
+    # query schedules for user_id and day_of_week
+    # if a schedule exists, reject the new assignment
+    # otherwise allow scheduler to continue
+    pass
+
+
+def validate_user_has_not_worked_more_than_five_days(connection, user_id):
+    # call storage.get_days_worked_by_user(connection, user_id)
+    # count distinct worked days with a loop
+    # reject if count is five or more
+    # otherwise allow assignment
+    pass
+
+
+def validate_shift_has_minimum_two_employees(connection, company_id, day_of_week, shift):
+    # query schedules for company_id, day_of_week, and shift
+    # count assigned employees
+    # if fewer than two, scheduler must add another available employee
+    pass
+
+
+def validate_employee_can_join_shift(connection, user_id, day_of_week, shift):
+    # check one-shift-per-day rule first
+    # check five-days-per-week rule second
+    # check shift coverage and capacity rules last
+    pass
+
+
+def validate_company_has_enough_employees(connection, company_id):
+    # get employee names by company
+    # reject schedule generation if company has fewer than two employees
+    # otherwise continue schedule generation
+    pass
diff --git a/src/scheduler/menu.py b/src/scheduler/menu.py
deleted file mode 100644
index e69de29..0000000
diff --git a/src/scheduler/models/__init__.py b/src/scheduler/models/__init__.py
index e69de29..330ed59 100644
--- a/src/scheduler/models/__init__.py
+++ b/src/scheduler/models/__init__.py
@@ -0,0 +1,3 @@
+from . import employee, schedule, shift
+
+__all__ = ["employee", "schedule", "shift"]
diff --git a/src/scheduler/models/employee.py b/src/scheduler/models/employee.py
index e69de29..f4a9574 100644
--- a/src/scheduler/models/employee.py
+++ b/src/scheduler/models/employee.py
@@ -0,0 +1,27 @@
+from scheduler.database import storage
+
+
+def define_employee_fields():
+    # include id from users table
+    # include company_id from company_users table
+    # include name and last_name from users table
+    # include preferred shift for each day of the week
+    # include optional priority ranking for bonus preference support
+    pass
+
+
+def register_employee_preference(connection, user_id, preference):
+    return storage.update_user_preference(connection, user_id, preference)
+
+
+def get_employee_names_by_company(connection, company_name):
+    company = storage.get_company_by_name(connection, company_name)
+    if company is None:
+        return None
+    return storage.get_employee_names_by_company(connection, company["id"])
+
+
+def register_user_into_company(connection, company_id, name, last_name, preference):
+    user = storage.add_user(connection, name, last_name, preference)
+    storage.add_company_user(connection, company_id, user["id"])
+    return user
diff --git a/src/scheduler/models/schedule.py b/src/scheduler/models/schedule.py
index e69de29..882520e 100644
--- a/src/scheduler/models/schedule.py
+++ b/src/scheduler/models/schedule.py
@@ -0,0 +1,23 @@
+from scheduler.database import storage
+
+
+def define_schedule_fields():
+    # include user_id to identify the employee
+    # include company_id if schedules need to be filtered by company
+    # include day_of_week for the assigned day
+    # include shift value for morning, afternoon, or evening
+    # include enter_time and out_time for clock-in and clock-out
+    pass
+
+
+def register_user_enter_and_out(connection, user_id, enter_time, day_of_week, out_time):
+    # Add manager validation before saving once scheduling rules are complete.
+    return storage.add_schedule(connection, user_id, enter_time, day_of_week, out_time)
+
+
+def output_weekly_schedule():
+    # group saved schedules by day of week
+    # inside each day, group schedules by shift
+    # list employee names for each shift
+    # show missing coverage when a shift has fewer than two employees
+    pass
diff --git a/src/scheduler/models/shift.py b/src/scheduler/models/shift.py
index e69de29..f75f536 100644
--- a/src/scheduler/models/shift.py
+++ b/src/scheduler/models/shift.py
@@ -0,0 +1,22 @@
+# Shift model guide.
+# Keep shift names consistent with the PostgreSQL work_time enum.
+
+
+def define_shift_values():
+    # morning maps to work_time value "morning"
+    # afternoon can map to "evening" if you keep the Rust enum name
+    # evening maps to work_time value "evening"
+    pass
+
+
+def define_day_values():
+    # use sunday through saturday to match the day_of_week enum
+    # loop over all seven days when generating the weekly schedule
+    pass
+
+
+def compare_shift_capacity():
+    # count employees assigned to one shift on one day
+    # if the count is fewer than two, scheduler must add another employee
+    # if the preferred shift is full, conflict manager must choose another shift
+    pass
diff --git a/src/scheduler/tui/screens/employees.py b/src/scheduler/tui/screens/employees.py
deleted file mode 100644
index e69de29..0000000
diff --git a/src/scheduler/tui/screens/menu.py b/src/scheduler/tui/screens/menu.py
deleted file mode 100644
index e69de29..0000000
diff --git a/src/scheduler/tui/screens/preferences.py b/src/scheduler/tui/screens/preferences.py
deleted file mode 100644
index e69de29..0000000
diff --git a/src/scheduler/tui/screens/schedule.py b/src/scheduler/tui/screens/schedule.py
deleted file mode 100644
index e69de29..0000000
diff --git a/src/scheduler/tui/styles/scheduler.tcss b/src/scheduler/tui/styles/scheduler.tcss
deleted file mode 100644
index e69de29..0000000