Reframe Module 9 worked-examples off already-built features (#40) (#70)

Co-authored-by: claude <claude@jpaul.io>
Co-committed-by: claude <claude@jpaul.io>

modules/09-issues-and-the-task-layer/README.md

@@ -165,16 +165,17 @@ for both.
 So how do you decide? A useful heuristic, which is really a property of the *issue*, not the model:
 
 **Hand it to an agent when the issue is well-scoped, has concrete acceptance criteria, and follows
-a pattern already in the codebase.** The `delete <index>` command is a strong candidate — it mirrors
-the existing `done` command almost exactly, "done" is unambiguous, and a human can verify the result
-in seconds. The bug above is another: contained, reproducible, testable.
+a pattern already in the codebase.** An `undone <index>` command — the inverse of `done` — is a
+strong candidate: it mirrors the existing command almost exactly, "clear the done flag" is
+unambiguous, and a human can verify the result in seconds. The bug above is another: contained,
+reproducible, testable.
 
 **Keep it with a human when the issue carries genuine ambiguity, design judgment, or cross-cutting
-risk.** "Add task priorities" sounds small but isn't: how many levels? Does the list re-sort? How are
-priorities displayed and stored? Those are product decisions an agent will *answer confidently and
-probably wrongly*, because nothing in the issue tells it the right call. A human resolves the
-ambiguity first (often by splitting it into clear sub-issues — at which point the pieces may become
-agent-ready).
+risk.** "Add due dates" sounds small but isn't: what date format does the user type? Does the list
+re-sort by date? How are overdue tasks shown, and in whose timezone? Those are product decisions an
+agent will *answer confidently and probably wrongly*, because nothing in the issue tells it the
+right call. A human resolves the ambiguity first (often by splitting it into clear sub-issues — at
+which point the pieces may become agent-ready).
 
 Notice the heuristic doesn't ask how smart the model is. It asks how well-specified the *work* is.
 A vague issue degrades gracefully with a human — they ask you a question — and catastrophically with
@@ -244,13 +245,17 @@ from whichever forge's web form you happen to be filling in.
 
 ### Part A — Find the work
 
-Look at the `tasks-app` and find three real pieces of work. You already know two from earlier
-modules; the app is deliberately thin, so there's plenty. Good candidates:
+Look at the `tasks-app` and find three real pieces of work. The app is deliberately thin, so there's
+plenty it still can't do. Because it's carried forward across modules, skip anything you may have
+already built (a `delete` command, task priorities) and pick work that's genuinely still missing.
+Good candidates:
 
 1. **A bug** — `python cli.py done 99` (an out-of-range index) and `python cli.py done abc` (a
    non-integer) both crash with an uncaught traceback. Run them and watch.
-2. **A small, patterned feature** — a `delete <index>` command, mirroring the existing `done` command.
-3. **A judgment-heavy feature** — task priorities (levels? sorting? display? storage?).
+2. **A small, patterned feature** — an `undone <index>` command that clears a task's done flag,
+   mirroring the existing `done` command (it's the inverse).
+3. **A judgment-heavy feature** — due dates on tasks (date format? sorting? overdue display?
+   storage?).
 
 ### Part B — Draft three well-formed issues
 
@@ -269,9 +274,9 @@ On your forge:
 2. Apply a small label set to each: a **type** (`bug`/`feature`), a **priority**, and — for the ones
    that qualify — a **`ready`** label meaning the acceptance criteria are solid enough to start.
 3. **Route them.** This is the module's core exercise:
-   - Assign the **judgment-heavy feature (priorities) to a human** — yourself. It has unresolved
+   - Assign the **judgment-heavy feature (due dates) to a human** — yourself. It has unresolved
      design questions; it is not agent-ready as written.
-   - Earmark the **bug** and the **`delete` feature for an agent.** They're well-scoped, patterned,
+   - Earmark the **bug** and the **`undone` feature for an agent.** They're well-scoped, patterned,
      and easy to verify. Use whatever your forge offers: an actual agent assignee, an `agent-ready`
      label, or just a note in the issue saying "suitable for an issue-to-PR agent (Module 25)." The
      mechanism doesn't matter yet; the *decision* does.

modules/09-issues-and-the-task-layer/lab/example-issues.md

@@ -6,6 +6,10 @@
   context (with repro for the bug), concrete acceptance criteria, and a stated scope.
 
   Note how the routing call is a property of the ISSUE (clear vs. ambiguous), not the model.
+
+  Because the tasks-app carries forward across modules, some commands you might reach for (a
+  `delete` command, task priorities) may already exist from earlier labs. These examples
+  deliberately target work the app does NOT have yet, so each reads as a genuine open issue.
 -->
 
 # Issue 1 — bug — route to AGENT
@@ -47,54 +51,56 @@ Changing how tasks are stored, numbered, or displayed.
 
 # Issue 2 — feature — route to AGENT
 
-# Title: Add a `delete <index>` command to remove a task
+# Title: Add an `undone <index>` command to mark a completed task as not done
 
 ## Context / problem
 
-There's no way to remove a task once added — only `add`, `list`, and `done`. Users accumulate stale
-tasks with no way to clear them. The command should mirror the existing `done <index>` command,
-which already takes an index and mutates the list.
+You can mark a task `done`, but there's no way to undo it — flag the wrong index by mistake and the
+only "fix" is to delete the task and re-add it. The command should mirror the existing `done <index>`
+command, which already takes an index and flips a task's state; this is simply its inverse.
 
 ## Acceptance criteria
 
-- [ ] `python cli.py delete <index>` removes the task at that index and saves.
-- [ ] `delete` with an out-of-range or non-integer index prints a clear error and exits non-zero
+- [ ] `python cli.py undone <index>` clears the done flag on the task at that index and saves.
+- [ ] `undone` with an out-of-range or non-integer index prints a clear error and exits non-zero
       (same behavior as the fixed `done`, see Issue 1).
-- [ ] `list` after a delete shows the remaining tasks, re-indexed.
-- [ ] Usage text mentions the new `delete` command.
+- [ ] `list` after `undone` shows that task as not done (`[ ]`).
+- [ ] Usage text mentions the new `undone` command.
 
 ## Out of scope
 
-Bulk delete / `clear all` (separate issue if wanted). Changing the storage format.
+A general multi-step undo / command history (separate concern). Changing the storage format.
 
 ## Proposed approach (optional)
 
-Add a `remove(index)` method on `TaskList` in `tasks.py` and wire a `delete` branch in `cli.py`,
-parallel to the existing `done` handling.
+Add a `reopen(index)` method on `TaskList` in `tasks.py` — the inverse of the existing `complete` —
+and wire an `undone` branch in `cli.py`, parallel to the existing `done` handling.
 
 ---
 - **Type:** feature
 - **Priority:** med
 - **Ready:** yes
-- **Route to:** agent — well-scoped and patterned directly on existing code; low ambiguity, easy to
-  verify.
+- **Route to:** agent — well-scoped and patterned directly on existing code (the inverse of `done`);
+  low ambiguity, easy to verify.
 
 
 # Issue 3 — feature — route to HUMAN
 
-# Title: Support task priorities
+# Title: Support due dates on tasks
 
 ## Context / problem
 
-Users want to mark some tasks as more important so the list reflects what to do first. Today every
-task is equal. This is desirable but underspecified — several product decisions have to be made
-before any code is written.
+Users want to attach a due date to a task so the list can reflect what's coming up, not just what
+exists. Today a task is only a title and a done flag. This is desirable but underspecified — several
+product decisions have to be made before any code is written.
 
 Open questions (resolve before this is `ready`):
-- How many priority levels? (high/med/low, or a numeric scale?)
-- Does `list` re-sort by priority, or just display it inline?
-- How is a priority set — at `add` time (a flag?) or with a separate command?
-- How is it stored, and what's the default for existing tasks?
+- What date format does the user type, and how forgiving is parsing? (ISO `2026-06-30` only, or
+  relative like `tomorrow` / `friday`?)
+- Does `list` re-sort by due date, group by it, or just display it inline?
+- How is a due date set — at `add` time (a flag?) or with a separate command? Can it be cleared?
+- How are overdue tasks surfaced — highlighted, flagged, sorted to the top — and in whose timezone?
+- How is it stored, and what's the default for the existing tasks that have none?
 
 ## Acceptance criteria