feat(tui): Dynamic Details - compact tool output with click-to-expand

[ryanwyler]

Summary

Keeps tool output compact and accessible with click-to-expand functionality. Tool blocks with more than 15 lines collapse by default, showing a preview with a "+N" indicator. Click anywhere on the tool block to expand/collapse, making it easier to navigate long sessions without pages of output scrolling by.

Fixes #7450 Relates to #1816

Also helps with:

• #5358 - Collapsible outputs improve tool output visibility
• #5419 - Less scrolling through verbose output improves screen real estate usage
• #6240 - Same goal of reducing visual clutter
• #3521 - Diffs are collapsed by default
• #5277 - Collapsed outputs save space on small screens

Compliments commit: https://github.com/anomalyco/opencode/commit/b3a2f9fb4

Features

• Tool outputs collapse when exceeding configured line threshold
• Click anywhere on tool block to expand/collapse
• Shows "+N" indicator for hidden lines
• Configurable threshold via tui.dynamic_details_max_lines (default: 15)
• Configurable arrow indicators via tui.dynamic_details_show_arrows (default: true)
• Toggle via Ctrl+P -> "Enable/Disable dynamic details"
• Persisted preference in KV store (default: enabled)

Configuration

{
  "tui": {
    "dynamic_details_max_lines": 15,
    "dynamic_details_show_arrows": true
  }
}

Applies To

Block-container tools (bash, write, edit, patch) when:

• Output exceeds configured line threshold
• Tool has completed (not pending/running states)

TodoWrite is excluded (always expanded) for visibility.

Implementation

Enhances the existing BlockTool component with collapse/expand logic rather than introducing new abstractions. Uses:

• Data-based line counting for collapse decisions (stable, based on tool output)
• Visual line counting via virtualLineCount for accurate "+N" display
• maxHeight + overflow: hidden for clipping when collapsed

Changes

• packages/opencode/src/cli/cmd/tui/routes/session/index.tsx - Add dynamicDetails context, toggle command, and collapse logic in BlockTool
• packages/opencode/src/config/config.ts - Add config options for max lines and arrow indicators