The internal helper that builds messages/tool-permission context for a session now also receives and forwards an appendSubagentSystemPrompt option alongside the existing customSystemPrompt and appendSystemPrompt, in the call that builds the session's tool permission context and original messages.
appendSubagentSystemPrompt threaded into more system-prompt construction call sites
Internal plumbing now threads a subagent-specific system prompt option through more call sites.
Under the hoodTier: how much it should matter to you
1Useful: my rating, 1 to 5
2Signal: worth watching, 1 to 5
ElsewhereArea: what it touches
Internal ChangesKind: in v2.1.252,
Internal ChangesSection of the release