01THE PRESSURE
Problem
Prompt rules can be persuaded away under persistent negotiation, even when the business rule is non-negotiable.
CASE STUDY / Agent-Transactable Commerce
Vendable
Sometimes reliability means removing the model from the critical path.
PythonMCPRazorpay
A commerce system exploring where agent negotiation must stop and deterministic entitlement enforcement must begin.
WHAT THIS PROVES
Deterministic safety / Idempotent replay / Audit chain / Red-team suite
LAB_03 / NEGOTIATION_GUARDFICTIONAL TRANSACTION
PROMPT RULE
Could you make an exception?
NEGOTIATING…STATUTORY GUARD
Published entitlement remains outside the model context.
MEDIAN HELD / 100%Interactive system walkthrough · simulated frontend data · not live telemetry
02THE SYSTEM
Approach
Keep the model in the conversational layer while enforcing entitlements in a small deterministic guard with no model call.
03THE MEASURE
Experiments
Compared system-prompt rules against a statutory guard across 105 recorded negotiation attempts.
04THE BREAK
Failure mode
Pure buyer persistence defeated prompt-only rules.
05THE JUDGMENT
Engineering decision
Move critical invariants out of probabilistic inference and into deterministic enforcement.
06THE EVIDENCE
Measured result
Across 105 recorded negotiations, a 7-line statutory guard held every median on the published entitlement.