fix(ai): fall back from codex websocket to sse (#4133)

packages/ai/src/utils/diagnostics.ts

@@ -0,0 +1,45 @@
+export interface DiagnosticErrorInfo {
+	name?: string;
+	message: string;
+	stack?: string;
+	code?: string | number;
+}
+
+export interface AssistantMessageDiagnostic {
+	type: string;
+	timestamp: number;
+	error?: DiagnosticErrorInfo;
+	details?: Record<string, unknown>;
+}
+
+export function formatThrownValue(value: unknown): string {
+	if (value instanceof Error) return value.message || value.name;
+	if (typeof value === "string") return value;
+	return String(value);
+}
+
+export function extractDiagnosticError(error: unknown): DiagnosticErrorInfo {
+	if (!(error instanceof Error)) return { name: "ThrownValue", message: formatThrownValue(error) };
+	const code = (error as Error & { code?: unknown }).code;
+	return {
+		name: error.name || undefined,
+		message: error.message || error.name,
+		stack: error.stack,
+		code: typeof code === "string" || typeof code === "number" ? code : undefined,
+	};
+}
+
+export function createAssistantMessageDiagnostic(
+	type: string,
+	error: unknown,
+	details?: Record<string, unknown>,
+): AssistantMessageDiagnostic {
+	return { type, timestamp: Date.now(), error: extractDiagnosticError(error), details };
+}
+
+export function appendAssistantMessageDiagnostic<T extends { diagnostics?: AssistantMessageDiagnostic[] }>(
+	message: T,
+	diagnostic: AssistantMessageDiagnostic,
+): void {
+	message.diagnostics = [...(message.diagnostics ?? []), diagnostic];
+}