Separate the computation layer from the language layer: agent business logic (e.g., synergy math, ledger reconciliation) must execute in deterministic, finance-approved code, while the LLM's prose output is treated as explanation rather than proof. The LLM is demoted from calculator to orchestrator/explainer.
This relocates the trust boundary: correctness becomes unit-testable and auditable in code, while the model's role narrows to interpretation and narration. Any agent that emits business-critical numbers from prompt prose has an unverifiable core.
For any agent producing numeric or financially material outputs, the authoritative path should be a deterministic function with the model supplying inputs, intent, and explanation—never the arithmetic or the rule evaluation itself.
Core math must run in deterministic, finance-approved code, not LLM prompt prose.
Model summaries are explanations, not proof.
LLM-generated prose or summaries cannot be used as proof of correct business logic.