A new flag, --system-prompt-snapshot <on|off>, is now passed to spawned agent and subagent processes and threaded through session state as systemPromptSnapshot across many call sites. It lets a forked or background session record the system prompt once and reuse it verbatim on resume or subsequent requests, instead of recomputing it live. It defaults to on for the built-in system prompt and off when --system-prompt or --append-system-prompt is passed.
New --system-prompt-snapshot CLI/agent option
A new --system-prompt-snapshot option makes a session record its system prompt once and reuse it on resume.
Use it nowTier: how much it should matter to you
5Useful: my rating, 1 to 5
4Signal: worth watching, 1 to 5
System PromptArea: what it touches
New FeaturesKind: in v2.1.257,
What probably matters to youSection of the release