Agents are fussy. They will not offer you missions
unless they, their corporation or their faction think highly enough of you. In game terms, the availability of an agent is affected by your effective standing
with the agent, corporation or faction and the level
of the agent.
For all agents except research and development agents
one or more of the effective standings between you and the agent, their corporation or faction must be greater than or equal to
((level-1) * 2.0) + (quality * 5.0)/100.0
With a high enough effective standing to a faction, all normal agents in that faction will be available to you. R & D agents
also require your effective standing to their corporation to be greater than or equal to
((level-2) * 2.0) + (quality * 5.0)/100.0
This forces you to run missions specifically for the agent's corporation if you wish to do research.
Read more about agent quality availability in the agent missions guide
Current EVE version
: 2.08.3582 (Exodus)