What is a standard operating procedure? (And why it drifts)
A standard operating procedure, or SOP, is the written version of how a repeating task gets done: onboarding a client, refunding an order, closing the books. Most teams have a few. Fewer have ones that match what people actually do, which is the part that matters once you hand the task to an AI agent.
What counts as an SOP
An SOP is a documented set of steps for a task that repeats often enough that variation costs money. In some industries a regulator requires it. FDA rule 21 CFR 211.100, titled "Written procedures; deviations", says drug makers must follow their written procedures, document the work as it happens, and that "any deviation from the written procedures shall be recorded and justified". ISO 9001 is looser. Its 2015 revision folded documents and records into one idea called documented information (clause 7.5) and left the amount up to the company.
Four shapes an SOP takes
Most SOPs land in one of four formats. A plain list of steps for short routines. A hierarchical version with nested numbering (1. Prepare the workstation, 1.1 Sanitize the surface) for longer work. A flowchart when the next step depends on the answer to a question. A checklist when done or not done is all that matters, like an opening or closing routine.
Where SOPs drift
The written SOP and the real one separate fast. One estimate puts the fork at three to six months, because whoever changes the process rarely goes back to change the document. Nobody notices while people run it: a person fills the gaps, asks a colleague, and figures out the odd case alone. An agent will not. Give it a procedure with an undefined exception and it handles the standard refund fine, then stalls on the unusual one.
So before automating anything, watch the task get done once and write down what the SOP left out. If a new hire could not follow your SOP unaided, an agent will not either.
Last updated: Sep 5, 2026