Tool cards disappeared on page refresh because assistant messages with
only tool_use content (no text) were filtered out of the visible
messages list. Since tool cards anchor to DOM rows via data-msg-idx,
removing the anchor row meant cards had nothing to attach to.
Fix: keep assistant messages in the render list if they contain
tool_use blocks, even when they have no text content. The row renders
with the role label but empty body, providing an anchor point for the
tool card insertion pass.
Fixes#140
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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