@arnilo/prism-policy

Optional policy-decision ledger and cursor-paginated audit export for Prism.

Install explicitly. Not in prism-code / prism-sdk profiles (Task 10 enrolls prism-all only).

Install

npm install @arnilo/prism-policy @arnilo/prism

Usage

import { assertIdentityActive, type AgentIdentity } from "@arnilo/prism";
import {
  createMemoryPolicyDecisionStore,
  createPolicyEvaluator,
  evaluateAndAppend,
  exportPolicyDecisions,
} from "@arnilo/prism-policy";

const evaluator = createPolicyEvaluator({
  policyId: "mail",
  policyVersion: "2026-07-23",
  evaluate: ({ action }) =>
    action === "mail.send"
      ? { outcome: "approval", reason: "external send", evidenceRefs: ["rule:external"] }
      : { outcome: "allow" },
});

const ledger = createMemoryPolicyDecisionStore({ requirePolicyVersion: "2026-07-23" });
assertIdentityActive(identity);
await evaluateAndAppend(
  { identity, action: "mail.send", resource: { kind: "draft", id: "d1" } },
  { store: ledger, evaluator, id: crypto.randomUUID() },
);

for await (const page of exportPolicyDecisions({
  store: ledger,
  tenantId: identity.tenantId,
  userId: identity.userId,
  sink: { async write(records) { /* host WORM / SIEM */ } },
})) {
  // page.items are redacted refs only
}

Ledger stores allow/deny/modify/approval with policy version, actor refs, target, reason, expiry, and evidence references. Unrestricted prompts/tool bodies are rejected. createFilePolicyDecisionStore({ path }) and memory storage are single-process/reference adapters.

For cross-replica PostgreSQL persistence, use createPostgresEnterpriseState({ pool }).policy from @arnilo/prism-enterprise-postgres; it preserves this PolicyDecisionStore contract with exact owner-bound pages and checksummed migration.

See Policy and audit and Enterprise PostgreSQL state.