MCP tool outputs can live in the memory layer

The user’s decision of 2026-10-07 (PLAN.md):

Saved and recalled per tool. MCP tool outputs can be saved to and retrieved from the memory layer. This is selectable per MCP server and tool, as a scoped setting.
Screened. The outputs pass the content guard’s screening and labelling at memory admission and at recall. Their provenance is the MCP server and the tool.
Referenced, not copied. Memory references the ledger’s content and never copies it (U-M2).