Scaled Kanban Board Implementation Plan

For agentic workers: REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (- [ ]) syntax for tracking.

Goal: Make the Issues Kanban board usable with hundreds of issues by adding compact high-volume rendering, collapsed cold lanes, and per-column reveal controls.

Architecture: Keep the change UI-only. IssuesList owns persisted board density preferences in existing company-scoped view state, while KanbanBoard owns lane rendering, card density, collapsed rails, and per-column "show more" state.

Tech Stack: React 19, TypeScript, Vite, Vitest/jsdom, @dnd-kit/core, @dnd-kit/sortable, Tailwind utility classes.

File Structure

Modify ui/src/components/IssuesList.tsx: extend IssueViewState, derive high-volume board preferences, add toolbar controls, pass props into KanbanBoard.
Modify ui/src/components/KanbanBoard.tsx: add compact cards, collapsed rail lanes, visible-card limits, and per-column reveal behavior.
Create ui/src/components/KanbanBoard.test.tsx: focused tests for high-volume behavior and drag/drop update callback.
Modify ui/src/components/IssuesList.test.tsx: update the mocked KanbanBoard expectations for new props.
Keep doc/plans/2026-05-05-scaled-kanban-board-design.md as the design source of truth.

Task 1: Add Kanban Board Scaling Mechanics

Files:

Modify: ui/src/components/KanbanBoard.tsx
Create: ui/src/components/KanbanBoard.test.tsx
Step 1: Write focused tests

Create ui/src/components/KanbanBoard.test.tsx with tests that render 60 todo issues and assert:

tsx

renderBoard({ issues: createIssues(60, "todo"), compactCards: true, initialVisibleCount: 10, revealIncrement: 10 });
expect(container.textContent).toContain("Showing 10 of 60");
expect(container.textContent).toContain("Show 10 more");

Also test collapsed rails:

tsx

renderBoard({ issues: createIssues(3, "done"), collapsedStatuses: ["done"] });
expect(container.textContent).toContain("Done");
expect(container.textContent).toContain("3");
expect(container.textContent).not.toContain("Issue 1");

Step 2: Run tests to verify failure

Run:

bash

pnpm exec vitest run ui/src/components/KanbanBoard.test.tsx

Expected: fail because KanbanBoard.test.tsx is new and the props/behavior do not exist.

Step 3: Implement minimal board behavior

In KanbanBoard.tsx, add exported constants:

export const KANBAN_BOARD_HIGH_VOLUME_THRESHOLD = 100;
export const KANBAN_COLUMN_PAGE_SIZE_OPTIONS = [10, 25, 50] as const;
export const KANBAN_COLUMN_DEFAULT_PAGE_SIZE = 10;
export const KANBAN_COLD_STATUSES = ["backlog", "done", "cancelled"] as const;

Extend props:

compactCards?: boolean;
collapsedStatuses?: string[];
initialVisibleCount?: number;
revealIncrement?: number;

Add per-status visible-count state keyed by status. Expanded columns render issues.slice(0, visibleCount) and show a button when hidden issues remain. Collapsed columns render a narrow droppable rail with status icon, label, and count, but no cards.

Reset per-status visible-count state when initialVisibleCount or revealIncrement changes so choosing a smaller cards-per-column preset does not leave a column expanded past the newly selected page size.

Step 4: Preserve drag/drop

Keep DndContext, SortableContext, and handleDragEnd status detection. Because collapsed rails use useDroppable({ id: status }), dropping a visible card onto a rail continues to resolve targetStatus through the existing status-id branch.

Step 5: Run focused test

Run:

bash

pnpm exec vitest run ui/src/components/KanbanBoard.test.tsx

Expected: pass.

Step 6: Commit

bash

git add ui/src/components/KanbanBoard.tsx ui/src/components/KanbanBoard.test.tsx
git commit -m "Scale kanban board columns"

Task 2: Wire Board Density State Into IssuesList

Files:

Modify: ui/src/components/IssuesList.tsx
Modify: ui/src/components/IssuesList.test.tsx
Step 1: Write/update tests

In IssuesList.test.tsx, update the KanbanBoard mock to capture:

compactCards?: boolean;
collapsedStatuses?: string[];
initialVisibleCount?: number;
revealIncrement?: number;

Add a test that stores board mode in localStorage, renders more than 100 issues, and expects:

expect(mockKanbanBoard).toHaveBeenLastCalledWith(expect.objectContaining({
  compactCards: true,
  collapsedStatuses: expect.arrayContaining(["backlog", "done", "cancelled"]),
  initialVisibleCount: 10,
  revealIncrement: 10,
}));

Step 2: Run test to verify failure

Run:

bash

pnpm exec vitest run ui/src/components/IssuesList.test.tsx

Expected: fail because IssuesList does not pass the new props yet.

Step 3: Add persisted board density preferences

Extend IssueViewState:

boardCardDensity: "auto" | "compact" | "comfortable";
boardColdLaneMode: "auto" | "collapsed" | "expanded";
boardColumnPageSize: 10 | 25 | 50;

Default the density modes to "auto" and page size to 10. Derive:

const boardHighVolume = viewState.viewMode === "board" && filtered.length > KANBAN_BOARD_HIGH_VOLUME_THRESHOLD;
const boardCompactCards = viewState.boardCardDensity === "compact"
  || (viewState.boardCardDensity === "auto" && boardHighVolume);
const boardCollapsedStatuses = viewState.boardColdLaneMode === "collapsed"
  || (viewState.boardColdLaneMode === "auto" && boardHighVolume)
    ? [...KANBAN_COLD_STATUSES]
    : [];

Step 4: Add toolbar controls

When viewState.viewMode === "board", add small outline/icon buttons near the existing view controls:

tsx

<Button ... title={boardCompactCards ? "Use comfortable cards" : "Use compact cards"}>...</Button>
<Button ... title={boardCollapsedStatuses.length > 0 ? "Expand cold lanes" : "Collapse cold lanes"}>...</Button>
<Button ... title="Cards per column">...</Button>
<Button ... title="Reset board density">...</Button>

Use lucide icons already available or import ChevronsDownUp, PanelTopClose, and RotateCcw.

Step 5: Pass board props

Update the KanbanBoard call:

tsx

<KanbanBoard
  issues={filtered}
  agents={agents}
  liveIssueIds={liveIssueIds}
  compactCards={boardCompactCards}
  collapsedStatuses={boardCollapsedStatuses}
  initialVisibleCount={viewState.boardColumnPageSize}
  revealIncrement={viewState.boardColumnPageSize}
  onUpdateIssue={onUpdateIssue}
/>

Step 6: Run focused tests

Run:

bash

pnpm exec vitest run ui/src/components/IssuesList.test.tsx ui/src/components/KanbanBoard.test.tsx

Expected: pass.

Step 7: Commit

bash

git add ui/src/components/IssuesList.tsx ui/src/components/IssuesList.test.tsx
git commit -m "Wire issue board density controls"

Task 3: Verification And PR Prep

Files:

Verify existing changes only.
Step 1: Run targeted UI tests

bash

pnpm exec vitest run ui/src/components/IssuesList.test.tsx ui/src/components/KanbanBoard.test.tsx

Expected: pass.

Step 2: Run broader cheap test path

bash

pnpm test

Expected: pass.

Step 3: Check worktree

bash

git status --short

Expected: only intentional changes before committing, or clean after final commit.

Step 4: Prepare PR

Read .github/PULL_REQUEST_TEMPLATE.md and use it for the PR body. Include:

design spec path
scaled Kanban behavior summary
test commands and results
Model Used section with the current Codex model details available in this session

Self-Review

Spec coverage: The plan covers compact high-volume board cards, collapsed cold lanes, cards-per-column presets, per-column reveal controls, persisted board preferences, current API reuse, and focused tests.
Placeholder scan: No unresolved markers or unspecified implementation placeholders remain.
Type consistency: The plan consistently uses boardCardDensity, boardColdLaneMode, boardColumnPageSize, compactCards, collapsedStatuses, initialVisibleCount, and revealIncrement.