ADR 0058: Extensions Page Density and Theme-Readable Button Surfaces

• Status: Accepted (IA amended by ADR 0112)
• Date: 2026-08-05
• Decision: D196

Context

The Extensions destination is a focused two-tab plugin surface: Installed and Marketplace. MCP, Skills, and Subagents are managed independently under Settings > Agent. The four-number overview band retained derived counts that were already represented by tab, group, and update states, consuming vertical space without adding a decision point. The shared button primitive also relied on gray-scale aliases and transparent text-mix fills, which made secondary actions and theme transitions too weak in dark mode.

Decision

1. Remove the numeric overview band and its four derived counters from the Extensions page. Keep the two tabs, Installed and Marketplace, with relevant counts, installed state groups, and pending-update alerts as the actionable hierarchy.
2. Define shared primary and secondary buttons with semantic theme tokens: primary buttons use --ds-accent and --ds-bg-primary; secondary buttons use --ds-bg-secondary, --ds-text-primary, and --ds-border-default. Hover states use --ds-accent-hover and --ds-bg-tertiary.
3. Treat this as a renderer presentation change only. Plugin, MCP, skill, marketplace, permission, host, protocol, and storage contracts do not change.

Consequences

• The page header and segmented control reach the useful content sooner and preserve more space for extension rows, cards, and editors.
• The source of truth for counts remains close to the surface it describes.
• Primary and secondary actions have an opaque, theme-correct surface and a visible semantic edge in both dark and light themes.
• Any future overview summary must introduce a distinct action or decision point rather than repeating tab or group state.

Alternatives considered

• Keep the overview band and reduce it to two cards: rejected because it still duplicates state and leaves the four-tab hierarchy uneven.
• Fix only the Extensions page buttons: rejected because the shared Button primitive is used across the app and the contrast defect is systemic.
• Add hard-coded per-theme colors: rejected because it would bypass the semantic token contract and make future theme changes harder.