diff --git a/packages/ai/src/api/pi-messages.ts b/packages/ai/src/api/pi-messages.ts
index 0af13f88..ee83f4ec 100644
--- a/packages/ai/src/api/pi-messages.ts
+++ b/packages/ai/src/api/pi-messages.ts
@@ -103,14 +103,11 @@ export class PiMessagesResponseError extends Error {
 	}
 }
 
-function isRecord(value: unknown): value is Record<string, unknown> {
-	return typeof value === "object" && value !== null && !Array.isArray(value);
-}
-
 function parsePiMessagesErrorBody(body: string): PiMessagesErrorBody | undefined {
 	try {
-		const parsed = JSON.parse(body) as unknown;
-		return isRecord(parsed) && isRecord(parsed.error) ? (parsed as PiMessagesErrorBody) : undefined;
+		const parsed = JSON.parse(body) as PiMessagesErrorBody | null;
+		const error = parsed?.error;
+		return parsed && typeof error === "object" && error !== null && !Array.isArray(error) ? parsed : undefined;
 	} catch {
 		return undefined;
 	}
diff --git a/packages/ai/src/providers/radius-config.ts b/packages/ai/src/providers/radius-config.ts
index dc96a300..a2715aae 100644
--- a/packages/ai/src/providers/radius-config.ts
+++ b/packages/ai/src/providers/radius-config.ts
@@ -23,28 +23,29 @@ export type RadiusOAuthCredential = OAuthCredential & {
 	gatewayConfig?: RadiusGatewayConfig;
 };
 
-function isRecord(value: unknown): value is Record<string, unknown> {
-	return typeof value === "object" && value !== null && !Array.isArray(value);
-}
-
 function isRadiusGatewayModel(value: unknown): value is RadiusGatewayModel {
+	if (typeof value !== "object" || value === null || Array.isArray(value)) return false;
+	const model = value as Partial<RadiusGatewayModel>;
 	return (
-		isRecord(value) &&
-		typeof value.id === "string" &&
-		typeof value.name === "string" &&
-		typeof value.reasoning === "boolean" &&
-		Array.isArray(value.input) &&
-		isRecord(value.cost) &&
-		typeof value.contextWindow === "number" &&
-		typeof value.maxTokens === "number"
+		typeof model.id === "string" &&
+		typeof model.name === "string" &&
+		typeof model.reasoning === "boolean" &&
+		Array.isArray(model.input) &&
+		typeof model.cost === "object" &&
+		model.cost !== null &&
+		!Array.isArray(model.cost) &&
+		typeof model.contextWindow === "number" &&
+		typeof model.maxTokens === "number"
 	);
 }
 
 function sanitizeRadiusGatewayConfig(config: unknown): RadiusGatewayConfig | undefined {
-	if (!isRecord(config) || typeof config.baseUrl !== "string" || !Array.isArray(config.models)) return undefined;
+	if (typeof config !== "object" || config === null || Array.isArray(config)) return undefined;
+	const { baseUrl, models } = config as Partial<RadiusGatewayConfig>;
+	if (typeof baseUrl !== "string" || !Array.isArray(models)) return undefined;
 	return {
-		baseUrl: config.baseUrl,
-		models: config.models.filter(isRadiusGatewayModel).map((model) => ({ ...model })),
+		baseUrl,
+		models: models.filter(isRadiusGatewayModel).map((model) => ({ ...model })),
 	};
 }
 
diff --git a/scripts/publish-model-catalog.mjs b/scripts/publish-model-catalog.mjs
index a8a30d43..922e19eb 100644
--- a/scripts/publish-model-catalog.mjs
+++ b/scripts/publish-model-catalog.mjs
@@ -65,10 +65,6 @@ function readJson(path) {
 	return JSON.parse(readFileSync(path, "utf8"));
 }
 
-function isRecord(value) {
-	return typeof value === "object" && value !== null && !Array.isArray(value);
-}
-
 function validateBundle(inputDir) {
 	const modelsPath = join(inputDir, "models.json");
 	const providerIndexPath = join(inputDir, "providers.json");
@@ -77,7 +73,9 @@ function validateBundle(inputDir) {
 	const models = JSON.parse(modelsBytes.toString("utf8"));
 	const providerIds = readJson(providerIndexPath);
 
-	if (!isRecord(models)) throw new Error("models.json must contain an object");
+	if (typeof models !== "object" || models === null || Array.isArray(models)) {
+		throw new Error("models.json must contain an object");
+	}
 	if (!Array.isArray(providerIds) || !providerIds.every((value) => typeof value === "string")) {
 		throw new Error("providers.json must contain an array of provider IDs");
 	}
@@ -93,13 +91,21 @@ function validateBundle(inputDir) {
 	let modelCount = 0;
 	for (const providerId of providerIds) {
 		const providerModels = models[providerId];
-		if (!isRecord(providerModels)) throw new Error(`Provider catalog must be an object: ${providerId}`);
+		if (typeof providerModels !== "object" || providerModels === null || Array.isArray(providerModels)) {
+			throw new Error(`Provider catalog must be an object: ${providerId}`);
+		}
 		const providerFile = readJson(join(providersDir, `${providerId}.json`));
 		if (!isDeepStrictEqual(providerFile, providerModels)) {
 			throw new Error(`Provider shard does not match models.json: ${providerId}`);
 		}
 		for (const [modelId, model] of Object.entries(providerModels)) {
-			if (!isRecord(model) || model.id !== modelId || model.provider !== providerId) {
+			if (
+				typeof model !== "object" ||
+				model === null ||
+				Array.isArray(model) ||
+				model.id !== modelId ||
+				model.provider !== providerId
+			) {
 				throw new Error(`Invalid model entry: ${providerId}/${modelId}`);
 			}
 			modelCount++;
@@ -181,13 +187,20 @@ function uploadJson(bucket, endpoint, sourcePath, key, cacheControl) {
 }
 
 function validateIndex(index) {
-	if (!isRecord(index) || index.schemaVersion !== CATALOG_SCHEMA_VERSION) {
+	if (
+		typeof index !== "object" ||
+		index === null ||
+		Array.isArray(index) ||
+		index.schemaVersion !== CATALOG_SCHEMA_VERSION
+	) {
 		throw new Error(`Existing ${CATALOG_INDEX_KEY} has an unsupported schema`);
 	}
 	if (!Array.isArray(index.catalogs)) throw new Error(`Existing ${CATALOG_INDEX_KEY} has no catalogs array`);
 	for (const catalog of index.catalogs) {
 		if (
-			!isRecord(catalog) ||
+			typeof catalog !== "object" ||
+			catalog === null ||
+			Array.isArray(catalog) ||
 			typeof catalog.minimumPiVersion !== "string" ||
 			typeof catalog.revision !== "string"
 		) {