[Compat] Claude Code v2.1.234: between-turn background task notifications now wrapped in <system-reminder> tags

[delexw]

Claude Code Version

v2.1.234 (August 17, 2026)

Change Description

Background task notifications delivered between turns are now sent to the model inside <system-reminder> tags, matching mid-turn delivery

Background-task notifications that arrive between turns are now wrapped in <system-reminder> tags in the message text, instead of whatever unwrapped/differently-formatted text was used before. Mid-turn delivery already used this wrapping; this just makes between-turn delivery consistent with it.

Impact on claude-code-trace

This is a content-level change inside a text block's string value (not a new field or entry type), but if claude-code-trace does any special-casing of <system-reminder>-wrapped text (e.g. to visually de-emphasize harness-injected reminders, or to filter them out of the main conversation view), background-task notifications delivered between turns will now start matching that special-casing where they previously didn't.

Severity: Low

Affected Parser Code

• Any text post-processing that detects/strips/styles <system-reminder>...</system-reminder> spans within message.content text blocks

Suggested Fix

• No structural change needed. If <system-reminder> detection exists, confirm it still correctly identifies these newly-wrapped background-task notifications as reminders (e.g. for de-emphasized styling) rather than ordinary assistant/user text.

Source

Claude Code v2.1.234 release notes, August 17, 2026.