Add model allow/deny policy helpers to ai-config

packages/ai-config/src/__tests__/resolve-models.test.ts

@@ -4,7 +4,12 @@
 
 import { describe, it, expect } from "vitest";
 
-import { resolveModels } from "../resolve-models.js";
+import {
+	isModelDiscoveryEnabled,
+	isModelIdAllowedByPolicy,
+	resolveModelIds,
+	resolveModels,
+} from "../index.js";
 import type { ModelInfoLike, ModelsBlock, ResolvedConnection } from "../types.js";
 
 function makeModel(id: string, overrides?: Partial<ModelInfoLike>): ModelInfoLike {
@@ -399,3 +404,57 @@ describe("resolveModels", () => {
 		expect(result[1].id).toBe("custom-1");
 	});
 });
+
+describe("model policy helpers", () => {
+	it("isModelDiscoveryEnabled treats discovery off as the only disabled state", () => {
+		expect([
+			isModelDiscoveryEnabled(undefined),
+			isModelDiscoveryEnabled({}),
+			isModelDiscoveryEnabled({ discovery: "auto" }),
+			isModelDiscoveryEnabled({ discovery: "off" }),
+		]).toEqual([true, true, true, false]);
+	});
+
+	it("resolveModelIds applies the complete resolver pipeline", () => {
+		const block: ModelsBlock = {
+			custom: [
+				{
+					id: "custom-1",
+					name: "Custom 1",
+					maxContextLength: 50000,
+					supportsTools: true,
+					supportsImages: false,
+					supportsToolResultImages: false,
+					supportsWebSearch: false,
+				},
+			],
+			allow: ["model-a", "model-b", "custom-1"],
+			deny: ["model-b"],
+		};
+
+		expect(resolveModelIds(block, ["model-a", "model-b", "model-c"])).toEqual([
+			"model-a",
+			"custom-1",
+		]);
+	});
+
+	it("isModelIdAllowedByPolicy checks the requested id, not unrelated custom declarations", () => {
+		const block: ModelsBlock = {
+			custom: [
+				{
+					id: "custom-1",
+					name: "Custom 1",
+					maxContextLength: 50000,
+					supportsTools: true,
+					supportsImages: false,
+					supportsToolResultImages: false,
+					supportsWebSearch: false,
+				},
+			],
+			allow: ["custom-1"],
+		};
+
+		expect(isModelIdAllowedByPolicy(block, "model-a")).toBe(false);
+		expect(isModelIdAllowedByPolicy(block, "custom-1")).toBe(true);
+	});
+});

packages/ai-config/src/index.ts

@@ -153,7 +153,12 @@ export {
 } from "./defaults.js";
 
 // --- Resolution helpers (public) -------------------------------------------
-export { resolveModels } from "./resolve-models.js";
+export {
+	isModelDiscoveryEnabled,
+	isModelIdAllowedByPolicy,
+	resolveModelIds,
+	resolveModels,
+} from "./resolve-models.js";
 
 // --- Bare-host base URL correction ------------------------------------------
 export {

packages/ai-config/src/resolve-models.ts

@@ -149,6 +149,36 @@ export function resolveModels(
 	return result.map((e) => attachRouting(e.model, e.userRouting, providerConnection));
 }
 
+/**
+ * Whether a provider should query runtime discovery for models.
+ */
+export function isModelDiscoveryEnabled(modelsBlock: ModelsBlock | undefined): boolean {
+	return modelsBlock?.discovery !== "off";
+}
+
+/**
+ * Resolve a provider's final model ids from discovered ids plus custom models.
+ * `discovery: "off"` drops discovered ids only; custom models still participate
+ * before overrides, allow, and deny.
+ */
+export function resolveModelIds(
+	modelsBlock: ModelsBlock | undefined,
+	discoveredModelIds: readonly string[],
+): string[] {
+	return resolveModels(
+		modelsBlock,
+		discoveredModelIds.map((id) => modelIdToModelInfo(id)),
+	).map((model) => model.id);
+}
+
+/** Checks whether a raw provider model id survives complete model policy resolution. */
+export function isModelIdAllowedByPolicy(
+	modelsBlock: ModelsBlock | undefined,
+	modelId: string,
+): boolean {
+	return resolveModelIds(modelsBlock, [modelId]).includes(modelId);
+}
+
 /**
  * Resolve protocol and endpoint for a model, applying the correct precedence:
  *
@@ -190,6 +220,18 @@ function attachRouting(
 	};
 }
 
+function modelIdToModelInfo(id: string): ModelInfoLike {
+	return {
+		id,
+		name: id,
+		maxContextLength: 0,
+		supportsTools: false,
+		supportsImages: false,
+		supportsToolResultImages: false,
+		supportsWebSearch: false,
+	};
+}
+
 /** Convert a custom model definition to a ModelInfoLike. */
 function customModelToModelInfo(custom: CustomModel): ModelInfoLike {
 	return {