- State the contract precisely: the cut never introduces a lone high
surrogate, and an unpaired surrogate the input already carries is not
repaired.
- Document the new export in the package README: a character-budget preview
section naming the persistent bash and pwsh shells and str_replace_editor,
plus a Known Limitations bullet that no longer contradicts it.
- Drop the assertion restatement from the two shell test comments.
- Let the str-replace test helper reuse a root so the clipped context reads
its file inside its own working directory.
Three tools capped the preview text they return with String.prototype.slice
at a UTF-16 code-unit budget. A cut that lands inside a surrogate pair
leaves a lone high surrogate, which is not well-formed text: a strict JSON
reader rejects the durable Session log carrying it, and the preview shows a
broken glyph. A lone surrogate retained in history has already blocked every
later Messages request for one session.
Centralize the cap in output-retention as
truncateWithoutSplittingSurrogatePair, and use it from the persistent bash
and pwsh shells and the string-replace editor. The cut drops the unpaired
half instead of keeping it, so the retained text stays a prefix and is at
most one code unit shorter than before.
The new dependency edges and the shifted Config sources regenerate
docs/module-graph and docs/config-catalog, including the committed
translation pair.
Refs #4817
mektpoy