Prompts can tell an agent to be careful. Policy layers define what careful means in a specific workflow, what evidence is required, who approves, and what happens if nobody answers.
Use prompt guardrails for style, preference, and broad caution.
Prompts are fast to change and useful for tone, priorities, prohibited actions, and simple heuristics. They become fragile when a repeated exception needs routing, proof, and accountability.
Use policy layers for durable boundaries.
- Payment thresholds
- Customer-impact replies
- Identity and account permissions
- Publishing and production edits
Auditability
Prompts rarely create a structured record. Policies create receipts: trigger, evidence, owner, response, timeout, and completion status.
Routing
Prompts can say ask a human. Policies specify which human, which channel, and which fallback.
Learning
Prompt failures are anecdotes. Policy receipts become a dataset for reducing unnecessary interruptions.