Unclear The new wording of the prompt is not shown, so what it changes in compaction is unknown.
What
When a conversation grows long, Claude Code compacts it, meaning it has Claude summarise the earlier parts to make room. Claude follows a system prompt, a set of standing instructions, while doing this. That main system prompt was rewritten, as measured in the prompt Claude Code actually sends.
The earlier version included a passage saying the most recent Claude models are the Claude 5 family, listing their model IDs, and advising to default to the latest and most capable models when building AI applications.
Why
Changing Claude's own instructions changes how it behaves, so summaries made during compaction may come out differently.
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubt
The new wording of the prompt is not shown, so what it changes in compaction is unknown.