diff --git a/packages/better-call/src/endpoint.ts b/packages/better-call/src/endpoint.ts
index fcb4851..96a9525 100644
--- a/packages/better-call/src/endpoint.ts
+++ b/packages/better-call/src/endpoint.ts
@@ -252,11 +252,11 @@ export type Endpoint<
 	(
 		context?: InputContext<Path, Method, Body, Query, false, false>,
 	): Promise<Awaited<R>>;
-	options: Omit<EndpointRuntimeOptions, "method" | "metadata"> & {
-		method: Method;
-		metadata?: Meta;
+	readonly options: Omit<EndpointRuntimeOptions, "method" | "metadata"> & {
+		readonly method: Method;
+		readonly metadata?: Meta;
 	};
-	path: Path;
+	readonly path: Path;
 };
 
 // Path + options + handler overload
diff --git a/packages/better-call/src/openapi.ts b/packages/better-call/src/openapi.ts
index c71c037..366ffb1 100644
--- a/packages/better-call/src/openapi.ts
+++ b/packages/better-call/src/openapi.ts
@@ -16,15 +16,15 @@ export interface OpenAPIParameter {
 	required?: boolean;
 	schema?: {
 		type: OpenAPISchemaType;
-		format?: string;
+		format?: string | undefined;
 		items?: {
 			type: OpenAPISchemaType;
 		};
 		enum?: string[];
 		minLength?: number;
-		description?: string;
-		default?: string;
-		example?: string;
+		description?: string | undefined;
+		default?: string | undefined;
+		example?: string | undefined;
 	};
 }