@arnilo/prism-model-router

Optional model governance router over Prism ProviderResolver: allow-list, residency, budgets, rate limits, circuit breaking, bounded fallbacks, redacted diagnostics, and an OpenRouter routing gate.

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

Install

npm install @arnilo/prism-model-router @arnilo/prism

Usage

import { createProviderResolver } from "@arnilo/prism";
import { createModelRouter } from "@arnilo/prism-model-router";
import { createPostgresEnterpriseState } from "@arnilo/prism-enterprise-postgres";

const enterprise = await createPostgresEnterpriseState({ pool, schema: "prism" });
const router = createModelRouter({
  resolver: createProviderResolver(providers),
  stateStore: enterprise.modelRouter,
  allowList: { providers: ["openai", "openrouter"], models: ["gpt-4o", "openrouter/auto"] },
  allowedResidencies: ["eu"],
  budgets: { maxTokens: 200_000, maxCostUsd: 5 },
  rateLimit: { maxRequests: 60, windowMs: 60_000 },
  circuit: { failureThreshold: 3, coolDownMs: 30_000 },
  fallbacks: [{ provider: "openrouter", model: "auto" }],
  allowOpenRouterRouting: false, // set true only when policy permits
  onDiagnostics: (d) => { /* optional @arnilo/prism-policy evidence ref */ },
});

const { provider, model, providerRequestPolicy, diagnostics } = await router.resolve({
  model: { provider: "openai", model: "gpt-4o" },
  identity,
  residency: "eu",
  maxCostUsd: 0.25,
});

// Resolve before provider I/O; durable state makes router methods async.
await router.recordUsage({ identity, provider: provider.id, model: model.model, tokens: 500 });
await router.recordOutcome({ identity, provider: provider.id, model: model.model, success: true });
await enterprise.close();

Without stateStore, the default memory state is process-local. With a durable state store, resolve, recordUsage, and recordOutcome require verified identity and must be awaited; synchronous providerSource throws rather than bypassing durable budgets/rates/circuits. See Model routing and Enterprise PostgreSQL state.