{"version":"2.1.321","anchor":"the-main-system-prompt-in-the-compaction-prompt-was-rewritte","canonical_anchor":"the-main-system-prompt-in-the-compaction-prompt-was-rewritte","heading":"The instructions Claude follows when compacting a conversation were rewritten","tier":"notice","area":"Compaction","scope":"individual","heads_up":false,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.321\/e\/the-main-system-prompt-in-the-compaction-prompt-was-rewritte","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.321","markdown":"### The instructions Claude follows when compacting a conversation were rewritten\n\nThe main system prompt Claude Code sends when it compacts a long conversation was rewritten\n\n**Unclear.** The new wording of the prompt is not shown, so what it changes in compaction is unknown.\n\n**What**\n\nWhen 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.\n\nThe 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.\n\n**Why**\n\nChanging Claude's own instructions changes how it behaves, so summaries made during compaction may come out differently.\n\n- Area: Compaction\n- Tier: You'll notice\n- Useful: 3\/5\n- Signal: 3\/5\n- Scope: individual\n- Heads-up: no"}