Capstone Brief: TaskNoter

You will build TaskNoter — a small but professional task manager CLI — independently. This brief gives requirements, constraints, and acceptance criteria. There is no reference solution: the three checkpoint challenges grade the decisions that matter, and your implementation choices are yours.

Requirements

1. Storage: SQLite table tasks(id INTEGER PRIMARY KEY, title TEXT NOT NULL UNIQUE, done INTEGER NOT NULL DEFAULT 0).
2. Repository: a class exposing add(title), get(task_id), complete(task_id), list_open() — all SQL parameterized, UNIQUE violations translated to a custom TaskError.
3. Service layer: functions annotated with type hints (str/int/bool/dict), validating input at the boundary and raising TaskError subclasses.
4. Interface: a main(argv) dispatcher for add <title> and list commands with correct exit codes (0 success, 2 usage error) and stderr error reporting.
5. Report: a function summarizing tasks as a dict with keys total and open counting all and open tasks.

Architecture constraints

• Layering: interface → domain/service → repository → sqlite. No SQL in the service or interface layers.
• No shell calls, no pickle, no hardcoded secrets. Errors are raised, not printed, below the interface layer.
• Behavior beats decoration: helper functions are fine; frameworks are not needed.

The three milestones (graded checkpoint challenges)

• Milestone 1 — Storage and Repository: schema + repository behavior (below, challenge 1).
• Milestone 2 — Service and Errors: typed validation boundary (challenge 2).
• Milestone 3 — Interface and Report: CLI dispatch + summary (challenge 3).

How to work (and with AI)

Write your own tests for each milestone before implementing (module 7's discipline). Use the AI mentor to critique designs, generate extra test cases, and review diffs — never to accept wholesale architecture. Submit each milestone's function signatures exactly as the challenges specify so the graders can verify your decisions.