[BUG] All output hidden in main view - only visible via Ctrl+O (detailed transcript)

Describe the bug
Since approximately April 1, 2026, Claude Code CLI shows no output in the main terminal view. All responses, tool results (diffs, bash output), and thinking are effectively hidden from the main view. The only way to inspect them is via Ctrl+O (detailed transcript).

The main view only shows status text like "Worked for Xs" or "Crunched for Xs".

I performed a full clean reinstall on April 3, 2026 and removed all plugins from settings. The problem still persists.

To reproduce

1. Start claude
2. Ask Claude to create or edit a file
3. Ask Claude to run a bash command
4. Observe that the main view shows no visible response text, no inline diffs, and no bash output
5. Press Ctrl+O and see that the underlying transcript/tool activity exists there

What I tried (none worked)

• Version downgrade from 2.1.90 to 2.1.86 and 2.1.79
• --verbose
• Removing "assistant": true from settings.json
• Disabling the Superpowers plugin
• Modifying cached GrowthBook feature flags in ~/.claude.json (tengu_sotto_voce, tengu_summarize_tool_results, tengu_marble_whisper, tengu_swann_brevity)
• Full clean reinstall with fresh minimal config and no plugins
• Testing --disable-slash-commands after the clean reinstall

Additional debugging detail
After the clean reinstall, plugins is empty, but the CLI still routes a simple prompt through SendUserMessage and ends with an empty result in JSON output.

Example behavior from claude -p --output-format json:

• request succeeds
• usage shows output tokens were generated
• result is an empty string

Example behavior from claude -p --verbose --output-format stream-json --include-partial-messages:

• assistant emits a SendUserMessage tool call containing the actual response text
• terminal-visible final result is still empty

This suggests the content exists internally but is being hidden/routed incorrectly in the normal terminal presentation layer.

Environment

• macOS on Apple Silicon (Apple M4)
• Apple Terminal 470
• Claude Code tested on 2.1.90, 2.1.86, 2.1.79
• Installed via global npm package: npm install -g @anthropic-ai/claude-code
• Problem reproduced again after clean reinstall on April 3, 2026

Expected behavior
Claude text responses, inline diffs, and bash output should be visible directly in the main terminal view instead of being hidden behind Ctrl+O.

Possibly related

• #41907