emo's Claude Code sessions hit "UserPromptSubmit hook error" on almost every
prompt. Root cause: the homelab-memory-recall.py UserPromptSubmit hook runs
`homelab memory recall <prompt>` and strict-decodes its stdout. printMemories
truncated each memory's preview with a BYTE slice (c[:240]), which cuts through
the middle of a 2-byte Cyrillic character and emits invalid UTF-8 (a dangling
0xd0 lead byte). The hook's subprocess.run(text=True) then raised
UnicodeDecodeError — not caught by its `except (TimeoutExpired, OSError)` — so
the hook exited non-zero and Claude surfaced the error. It is Cyrillic-specific
(ASCII has no multibyte chars to split), so it bit emo (Bulgarian prompts) every
turn while English users almost never saw it.
Two-layer fix:
- cli: truncatePreview() now counts RUNES, not bytes, so the preview never
splits a character. Regression test asserts valid UTF-8 on a long Cyrillic
string. Fixes the root for every consumer of `memory recall` / `memory list`.
- hook: subprocess.run gains errors="replace" and the except is broadened to
honor the script's own "best-effort, exit 0" contract — so a truncated or
otherwise odd payload can never again surface as a hook error.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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