Taking a Single-User Harness to a Shared Team Instance

An internal harness has worked well for eighteen months: it runs on one engineer's workstation, reads a secrets.env file next to its config, executes tools in the engineer's own shell, appends a newline-delimited log to ~/agent.log, and keeps a persistent memory file the agent may append to and which is auto-loaded into every session.

The team now wants to host it so twelve engineers share one instance.

1. Go through the design and name what breaks — being specific about the failure each choice produces at twelve users that it did not produce at one.
2. Propose the replacement design for each.
3. One engineer argues the persistent memory file is the feature that makes the agent good and must be preserved as-is. Respond.