"Specific brief" refers to a clear and precise set of instructions or guidelines for a task or project. It outlines what needs to be done, how it should be done, and any other important details. Full definition
Gibb, previously the schools minister, now has a more specific brief. (schoolsweek.co.uk)
The Office intends to develop a specific briefing paper that helps explain to intermediaries the implications of key trading frameworks and rules, such as the Commonwealth Environmental Water trading framework, Commonwealth Procurement Rules and Basin Plan Trading Rules. (environment.gov.au)
I would say however that Coquelin did look good and in that spell mentioned and believe for two reasons — 1) playing alongside Cazorla and 2) he had a specific brief what do alongside Cazorla. (justarsenal.com)