[BUG] [VS Code Sidebar] Fable 5 doesn't show text responses in chat

This looks like the same underlying bug I filed in #76032 (Desktop Code-session transcript). One clarification from controlled testing that may help triage: the assistant text is actually emitted — it's present in the local session .jsonl — but the transcript renderer drops it in spans that also contain an AskUserQuestion/ExitPlanMode call. So it's likely a renderer drop specific to Fable-5's output shape, not the model staying silent.

In a 2×2 (Fable-5 vs Opus-4.8 × text-and-dialog-same-turn vs separated), Opus-4.8 lost no text across ~11 trials while Fable-5 lost ~50% with the identical structure — matching your Fable-5-vs-Opus-4.8 observation. Cross-linking for the maintainers.

#65620?

Same bug, with session-transcript evidence: the text is not only unrendered — it is also missing from the local session JSONL (VS Code extension, Windows, CLI 2.1.207, claude-fable-5, plan mode)

Environment

• Claude Code v2.1.207, VS Code native extension (sidebar), Windows 11 Pro (build 26200)
• Model: claude-fable-5, plan mode active for the whole session
• Still reproduces on 2.1.207 (this issue was filed on 2.1.205)

What happened

Twice in one session the assistant emitted a multi-paragraph markdown text block (Hebrew/RTL) immediately followed by an AskUserQuestion call in the same turn. In both cases only the question dialog rendered; the explanatory text never appeared. The second occurrence was the worst case UX-wise: the dropped text was the explanation the user had explicitly just asked for, and the dialog then asked them to choose between options that only made sense given that explanation — an effectively context-free dialog. The user had to interrupt and ask where the answer went.

Transcript-level evidence

Inspecting the session JSONL (~/.claude/projects/<project>/<session-id>.jsonl) after the fact:

• The entire session contains exactly one assistant text block — the very first assistant message of the conversation (which did render, and which itself preceded tool calls in the same turn).
• Every subsequent mid-turn text block is gone. The affected spans are persisted as thinking (empty) → thinking (empty) → tool_use with no text record at all:

assistant thinking (empty)
assistant tool_use Agent              ← preceding status text missing
assistant thinking (empty) ×2
assistant tool_use AskUserQuestion    ← preceding ~150-word text block missing
assistant thinking (empty) ×2
assistant tool_use AskUserQuestion    ← preceding ~450-word, two-section markdown text missing

Data points for triage

1. The drop is dual: not rendered and not persisted to the JSONL. This matches the mechanism documented in #67267 (terminal/tmux) — now confirmed on the VS Code extension surface.
2. Not exclusive to AskUserQuestion: text emitted before an Agent (subagent) tool call was dropped the same way.
3. Nondeterministic: the first turn's text also preceded tool calls in the same turn, yet persisted and rendered — consistent with #67426.
4. Model correlation consistent with #76032 / #67166: observed on claude-fable-5; per those reports Opus 4.8 is unaffected.
5. Because the text is also absent from the JSONL, --resume / transcript review cannot recover it; the content is simply lost to the user.

Session id withheld from the public thread for privacy; available to Anthropic staff on request (also submitted via the in-product /bug channel).