[BUG] VS Code extension: copying an assistant message from the chat pane yields garbled/concatenated text (unpasteable)

What happens

Selecting and copying text from an assistant response in the Claude Code chat pane (VS Code extension) puts mangled text on the clipboard — it appears to be an internal serialized/concatenated representation rather than the visible markdown. Pasting into any other application (text editor, Word, Slack, etc.) yields unusable/garbled text.

Expected

Copy should place the plain readable text (or the underlying clean markdown) of the selection on the clipboard, pasteable normally into any app.

Steps to reproduce

1. In the VS Code Claude Code extension, open a conversation with an assistant response containing formatted markdown (headings, tables, lists).
2. Select part or all of the response in the chat pane.
3. Copy (Cmd+C).
4. Paste into any other application.

Actual: garbled / concatenated text, not the visible content.

Workaround

Ask Claude to write the content to a .md file and copy from the file instead.

Environment

• Claude Code VS Code extension
• Claude Code version: 2.0.55 (Claude Code)
• VS Code: 1.131.0 (arm64)
• OS: macOS (Darwin 25.5.0), Apple Silicon

Possibly related, but appears distinct (this one is copy-out from the VS Code extension chat pane, which none of these cover):

• #71793 — VS Code extension clipboard, but the paste-into direction (image priority)
• #79482 — /copy writes latin-1 mojibake, but that is the TUI /copy command
• #72455 — system-wide clipboard corruption, but that is the Terminal.app TUI fullscreen renderer