TUI: copying assistant output strips spaces & drops wrapped lines on paste (Copilot/Gemini panes unaffected)

Summary

Copying assistant output out of the Claude Code TUI pane corrupts it on paste: spaces are stripped (words run together) and/or wrapped long-line content is dropped (a whole paragraph vanishes mid-line). Short, non-wrapping lines copy fine.

Environment

• Claude Code: 2.1.170 (Claude Code)
• OS: Linux 5.15 (NVIDIA Jetson Orin Nano, aarch64)
• Multiplexer: tmux
• Access: remote over SSH from an iPad terminal

What happens

Selecting a multi-sentence paragraph of assistant output and copying it yields corrupted text:

• Spaces removed — actual paste: whatwouldgetyourSMSregistrationrejectedbeforeyousubmit,andgivesyoutheexactfixes
• Or the wrapped middle of a paragraph is omitted entirely — text appears up to one word, then jumps to a much later word, with the body gone.

Key isolating signal

In the same tmux session and same terminal, copying from the Copilot CLI and Gemini CLI panes works perfectly. Only text rendered by the Claude Code TUI is affected. This points to Claude Code's TUI rendering / line-wrapping (vs. plain line-based output) as the cause — not tmux, not the terminal app.

Repro

1. In Claude Code (TUI), have the assistant print a multi-sentence paragraph that wraps across several rows.
2. Select that paragraph in the terminal and copy.
3. Paste into any other app.

Expected: identical text. Actual: spaces stripped and/or wrapped content dropped.

Impact

Can't reliably copy generated content (messages, code snippets) out of the CLI; have to route everything through files or external docs.

Workaround

Write the text to a file and cat it in a plain (non-Claude) pane — that copies cleanly.