diff --git a/src/tts/provider-error-utils.test.ts b/src/tts/provider-error-utils.test.ts
deleted file mode 100644
index c57623172b2..00000000000
--- a/src/tts/provider-error-utils.test.ts
+++ /dev/null
@@ -1,37 +0,0 @@
-import { describe, expect, it } from "vitest";
-import {
-  assertOkOrThrowProviderError,
-  extractProviderErrorDetail,
-  extractProviderRequestId,
-} from "./provider-error-utils.js";
-
-describe("provider error utils", () => {
-  it("formats nested provider error details with request ids", async () => {
-    const response = new Response(
-      JSON.stringify({
-        detail: {
-          message: "Quota exceeded",
-          status: "quota_exceeded",
-        },
-      }),
-      {
-        status: 429,
-        headers: { "x-request-id": "req_123" },
-      },
-    );
-
-    await expect(assertOkOrThrowProviderError(response, "Provider API error")).rejects.toThrow(
-      "Provider API error (429): Quota exceeded [code=quota_exceeded] [request_id=req_123]",
-    );
-  });
-
-  it("reads string error fields and fallback request id headers", async () => {
-    const response = new Response(JSON.stringify({ error: "Invalid API key" }), {
-      status: 401,
-      headers: { "request-id": "fallback_req" },
-    });
-
-    expect(await extractProviderErrorDetail(response)).toBe("Invalid API key");
-    expect(extractProviderRequestId(response)).toBe("fallback_req");
-  });
-});
diff --git a/src/tts/provider-error-utils.ts b/src/tts/provider-error-utils.ts
deleted file mode 100644
index 5d99dc453e7..00000000000
--- a/src/tts/provider-error-utils.ts
+++ /dev/null
@@ -1,152 +0,0 @@
-export { asFiniteNumber } from "../shared/number-coercion.js";
-import { normalizeOptionalString as trimToUndefined } from "../shared/string-coerce.js";
-export { normalizeOptionalString as trimToUndefined } from "../shared/string-coerce.js";
-
-export function asBoolean(value: unknown): boolean | undefined {
-  return typeof value === "boolean" ? value : undefined;
-}
-
-export function asObject(value: unknown): Record<string, unknown> | undefined {
-  return typeof value === "object" && value !== null && !Array.isArray(value)
-    ? (value as Record<string, unknown>)
-    : undefined;
-}
-
-export function truncateErrorDetail(detail: string, limit = 220): string {
-  return detail.length <= limit ? detail : `${detail.slice(0, limit - 1)}…`;
-}
-
-export async function readResponseTextLimited(
-  response: Response,
-  limitBytes = 16 * 1024,
-): Promise<string> {
-  if (limitBytes <= 0) {
-    return "";
-  }
-  const reader = response.body?.getReader();
-  if (!reader) {
-    return "";
-  }
-
-  const decoder = new TextDecoder();
-  let total = 0;
-  let text = "";
-  let reachedLimit = false;
-
-  try {
-    while (true) {
-      const { value, done } = await reader.read();
-      if (done) {
-        break;
-      }
-      if (!value || value.byteLength === 0) {
-        continue;
-      }
-      const remaining = limitBytes - total;
-      if (remaining <= 0) {
-        reachedLimit = true;
-        break;
-      }
-      const chunk = value.byteLength > remaining ? value.subarray(0, remaining) : value;
-      total += chunk.byteLength;
-      text += decoder.decode(chunk, { stream: true });
-      if (total >= limitBytes) {
-        reachedLimit = true;
-        break;
-      }
-    }
-    text += decoder.decode();
-  } finally {
-    if (reachedLimit) {
-      await reader.cancel().catch(() => {});
-    }
-  }
-
-  return text;
-}
-
-export function formatProviderErrorPayload(payload: unknown): string | undefined {
-  const root = asObject(payload);
-  const detailObject = asObject(root?.detail);
-  const subject = asObject(root?.error) ?? detailObject ?? root;
-  if (!subject) {
-    return undefined;
-  }
-  const message =
-    trimToUndefined(subject.message) ??
-    trimToUndefined(subject.detail) ??
-    trimToUndefined(root?.message) ??
-    trimToUndefined(root?.error) ??
-    trimToUndefined(root?.detail);
-  const type = trimToUndefined(subject.type);
-  const code = trimToUndefined(subject.code) ?? trimToUndefined(subject.status);
-  const metadata = [type ? `type=${type}` : undefined, code ? `code=${code}` : undefined]
-    .filter((value): value is string => Boolean(value))
-    .join(", ");
-  if (message && metadata) {
-    return `${truncateErrorDetail(message)} [${metadata}]`;
-  }
-  if (message) {
-    return truncateErrorDetail(message);
-  }
-  if (metadata) {
-    return `[${metadata}]`;
-  }
-  return undefined;
-}
-
-export async function extractProviderErrorDetail(response: Response): Promise<string | undefined> {
-  const rawBody = trimToUndefined(await readResponseTextLimited(response));
-  if (!rawBody) {
-    return undefined;
-  }
-  try {
-    return formatProviderErrorPayload(JSON.parse(rawBody)) ?? truncateErrorDetail(rawBody);
-  } catch {
-    return truncateErrorDetail(rawBody);
-  }
-}
-
-export function extractProviderRequestId(response: Response): string | undefined {
-  return (
-    trimToUndefined(response.headers.get("x-request-id")) ??
-    trimToUndefined(response.headers.get("request-id"))
-  );
-}
-
-export function formatProviderHttpErrorMessage(params: {
-  label: string;
-  status: number;
-  detail?: string;
-  requestId?: string;
-}): string {
-  const { label, status, detail, requestId } = params;
-  return (
-    `${label} (${status})` +
-    (detail ? `: ${detail}` : "") +
-    (requestId ? ` [request_id=${requestId}]` : "")
-  );
-}
-
-export async function createProviderHttpError(response: Response, label: string): Promise<Error> {
-  const detail = await extractProviderErrorDetail(response);
-  const requestId = extractProviderRequestId(response);
-  return new Error(
-    formatProviderHttpErrorMessage({
-      label,
-      status: response.status,
-      detail,
-      requestId,
-    }),
-  );
-}
-
-export async function assertOkOrThrowProviderError(
-  response: Response,
-  label: string,
-): Promise<void> {
-  if (response.ok) {
-    return;
-  }
-  throw await createProviderHttpError(response, label);
-}