With the agent the -i flag or IdentityFile config option is not honored. You then must maintain different agents, one for each distinct set of keys you want to

With the agent the -i flag or IdentityFile config option is not honored. You then must maintain different agents, one for each distinct set of keys you want to use. The ssh-ident package helps do this. Or, you must insert a filter proxy between the real agent and the ssh client. The ssh-agent-filter package helps do this.