The engine reads the group owning the accessed path at apply and gives it to the containers and the tools' account an access's new `grant` names: --group-add for a container (recreated with it), an account group for the account (recorded, taken back as ADR 0252 takes back). The path is never changed; an access whose group cannot write is stated unhealthy for the operator to decide; group 0 and the root-granting groups are refused by name. The tool runner restarts through the restart-on the controller gives it, because the access reports updated exactly when the account's groups moved. Health says GrantContract (4), which tells the controller it may send `grant`.