ADR 0066: Empty home direct bottom composer

• Status: Accepted for implementation
• Date: 2026-08-07
• Deciders: PI-Desktop core
• Amends: D111
• Amended by: ADR 0067 (starter-grid presentation only; superseded by D206)

Context

The empty chat home placed contextual prompt buttons between the hero and the composer. Those controls added an extra decision before the first task and made the composer part of the scrollable content stack. Optional onboarding content could therefore push the primary task-entry surface away from the bottom of the chat area.

Decision

1. Remove the former empty-home contextual quick-action row and its project-opening buttons. The current surface also omits the separate developer starter grid introduced by ADR 0067 (D206).
2. Keep the hero and optional onboarding checklist inside .home-scroll, the only vertical overflow surface for empty-home content.
3. Render the home composer in a sibling .home-composer-wrap after the scroller. The wrapper is flex-fixed at the bottom of home-main-content with the existing content width and bottom spacing, so the composer remains visible while the content region scrolls independently.
4. Preserve the checklist's existing inline actions and dismissal behavior. Short windows may scroll the checklist, but the composer must not cover it.

Consequences

• Empty home has one direct task-entry path and a quieter, purpose-built guidance surface above it.
• The composer remains stable at the bottom in both empty-home and transcript states.
• Optional onboarding remains reachable without an overlay or a second scroll surface.
• The former prompt-template row, quick-action styling, and developer starter cards are not part of the renderer surface.

Alternatives considered

Keep the quick-action row and only move the composer

Rejected. The requested surface is direct task entry; retaining the buttons would preserve the extra decision layer and its unused prompt-prefill path.

Keep the composer inside the scroller and align it with margin-top: auto

Rejected. Optional checklist growth would still move the composer, and a short-window overflow could make the primary input less predictable.

Absolute-position the home composer over the scroller

Rejected. A bottom overlay can cover checklist rows unless every content block reserves and tracks the composer's changing multi-line height.

References

• docs/spec/04-ux/01-ui-ia.md
• docs/spec/04-ux/07-ui-design-system.md
• docs/spec/04-ux/08-component-spec.md
• docs/spec/06-delivery/04-e2e-test-plan.md (E2E-063, US-UI-31, US-UI-64)
• docs/spec/08-meta/decisions-log.md (D111, D131, D204, D206)