Follow-up to #23863 (CJK table alignment). The realigner was
correctly padding pipes to identical column offsets, but when a
table's natural width exceeds terminal cells it produced lines that
the terminal soft-wrapped mid-cell, destroying column alignment
visually even though the bytes were perfectly padded. Reported as
'columns are not aligned' on tables containing one long row alongside
several short rows.
Approach mirrors Claude Code's MarkdownTable.tsx narrow-terminal
fallback: when realign_markdown_tables is given an available_width
budget and the rebuilt horizontal table exceeds it, render each body
row as 'Header: value' lines separated by a thin ─ rule. Word-wraps
oversize values at the budget with a 2-space continuation indent.
- agent/markdown_tables.py: realign_markdown_tables(text, available_width=None);
threshold check at the top of _render_block flips into a new
_render_vertical fallback. Includes _wrap_to_width with hard-break
for tokens longer than the budget.
- cli.py: helper _terminal_width_for_streaming() returns
shutil.get_terminal_size().columns minus _STREAM_PAD and a 2-cell
safety margin; passed to all three realign call sites
(_render_final_assistant_content for strip+render Panel paths, and
the streaming flushers in _emit_stream_text / _flush_stream).
- tests/agent/test_markdown_tables.py: 4 new tests covering the
overflow-vertical fallback for ASCII + CJK content, the
'fits → keep horizontal' case, and the long-cell wrap with indent.
Live-verified: with COLUMNS=100, the user's reported 'long row in
ASCII table' case now renders as vertical key-value rows that all fit
the panel; the 6-column CJK comparison table still renders as an
aligned horizontal table because it fits inside 100 cols.
CJK and emoji glyphs render as two terminal cells but JS String#length
and the model's own padding count them as one, so any markdown table
with Chinese / Japanese / Korean cells drifts right per row when a
real terminal renders it. Both surfaces fix this with a display-cell
width measurement (wcswidth on the Python side, stringWidth on the
TUI side).
Changes:
- agent/markdown_tables.py: new helper. realign_markdown_tables(text)
detects markdown table blocks (header + |---| divider) and
rewrites the row padding using wcwidth.wcswidth so every pipe and
dash lines up across rows. No-op on text without tables.
- cli.py: hook the helper into _render_final_assistant_content for
strip / render modes (raw passes through untouched), and into the
streaming line emitter so live token-by-token rendering also
produces aligned tables. A small two-buffer state machine in
_emit_stream_text holds table rows until the block ends, then
flushes them through the realigner so all rows pad to a single
per-column width.
- ui-tui/src/components/markdown.tsx: renderTable now uses
stringWidth (Bun.stringWidth fast path + East-Asian-width-aware
fallback, already memoised in @hermes/ink) instead of UTF-16
String#length for both column-width measurement and per-cell
padding. Drops the comment that documented the bug as a deliberate
limitation.
Validation:
- New tests/agent/test_markdown_tables.py (11): every rebuilt block
shares pipe column offsets across rows for pure CJK, mixed
CJK+emoji, ragged-row, and multi-table inputs.
- Updated tests/cli/test_cli_markdown_rendering.py: the existing
strip-mode test asserted exact whitespace; rewritten to assert the
alignment contract (cell content survives + every rendered row
shares pipe offsets).
- New ui-tui markdown.test.ts case (1): rendered column-2 start
offset is identical for the header + every body row, including
the CJK row that drifted before the fix.
- Live: hermes chat -q with the user-reported screenshot prompt now
produces a perfectly aligned table on the wire (header, divider,
4 body rows including '通义千问', all pipes at identical columns).
