In finance, auditability is the binding constraint
Most AI deployments are judged on accuracy. Finance automation is judged on
whether an auditor can reconstruct a decision six months later. A posting that is
correct but unexplainable will still fail review, and the automation gets switched
off.
That reframes the engineering. The extraction model matters less than the evidence
chain around it: which document produced this value, what confidence did the
extraction have, which tolerance rule permitted automatic posting, what version of
that rule was in force, and who released it. All of that has to be written at the
time of the posting, not reconstructed afterwards.
Tolerances are rules, not judgements
A recurring mistake is letting the model decide whether a variance is acceptable.
It should never be asked. Tolerances are business policy — configured per supplier,
category and value band, versioned, and enforced in code.
The model’s job is narrower and more useful: read the documents accurately,
determine what matches, and explain what does not. The decision on an
out-of-tolerance variance belongs to a person, and the agent’s contribution is
making that decision take thirty seconds instead of twenty minutes.
Segregation of duties still applies
Automation does not exempt a process from control requirements. The agent prepares;
a named human releases. Keeping those separate is what lets the system pass review
in the first place — and it is why we scope payment execution out entirely. The
agent never moves money.