diff --git a/open-sse/services/accountFallback.ts b/open-sse/services/accountFallback.ts
index 0efddc1762..1ade866731 100644
--- a/open-sse/services/accountFallback.ts
+++ b/open-sse/services/accountFallback.ts
@@ -33,6 +33,7 @@ import { resolveUseUpstream429BreakerHints } from "../../src/shared/utils/provid
 import { getCodexModelScope } from "../config/codexQuotaScopes.ts";
 import { getQuotaScopedModelForProvider } from "./antigravityQuotaFamily.ts";
 import { isRpdExhausted, isRpmExhausted } from "./geminiRateLimitTracker.ts";
+import { parseRetryHintFromJsonBody } from "./retryAfterJson.ts";
 
 export type ProviderProfile = {
   baseCooldownMs: number;
@@ -1035,22 +1036,15 @@ function parseDelayString(value: unknown): number | null {
   return Number.isNaN(num) ? null : num * 1000;
 }
 
-/**
- * T07: Parse retry time from error text body with combined "XhYmZs" format.
- * Examples: "Your quota will reset after 2h30m14s", "reset after 45m", "reset after 30s"
- * Returns milliseconds or null if not parseable.
- *
- * @param {string} errorText - Error message text from response body
- * @returns {number|null} Retry duration in milliseconds
- */
+// T07: parse retry time from error text body with combined "XhYmZs" format.
 export function parseRetryFromErrorText(errorText: unknown): number | null {
   if (!errorText || typeof errorText !== "string") return null;
   const msg: string = String(errorText);
 
-  // Issue #2321: Anthropic OAuth occasionally embeds an absolute ISO 8601
-  // timestamp instead of a relative duration (e.g. "Try again at
-  // 2026-05-17T10:00:00Z" or "Please wait until 2026-05-17T10:00:00.000Z").
-  // Convert to a future-duration in milliseconds if it parses.
+  const bodyHintMs = parseRetryHintFromJsonBody(msg, MAX_PROVIDER_COOLDOWN_MS);
+  if (bodyHintMs !== null) return bodyHintMs;
+
+  // Issue #2321: parse embedded absolute ISO retry timestamps.
   const isoMatch =
     /\b(?:try again at|wait until|reset(?:s)? at|available at|retry after)\s+(\d{4}-\d{2}-\d{2}[Tt ]\d{2}:\d{2}(?::\d{2})?(?:\.\d+)?(?:Z|[+-]\d{2}:?\d{2})?)/i.exec(
       msg
diff --git a/open-sse/services/retryAfterJson.ts b/open-sse/services/retryAfterJson.ts
new file mode 100644
index 0000000000..1426fc3447
--- /dev/null
+++ b/open-sse/services/retryAfterJson.ts
@@ -0,0 +1,44 @@
+type JsonRecord = Record<string, unknown>;
+
+function objectRecord(value: unknown): JsonRecord {
+  return value && typeof value === "object" && !Array.isArray(value) ? (value as JsonRecord) : {};
+}
+
+function positiveCappedMs(value: unknown, maxMs: number): number | null {
+  return typeof value === "number" && Number.isFinite(value) && value > 0
+    ? Math.min(value, maxMs)
+    : null;
+}
+
+function futureTimestampMs(value: unknown, maxMs: number): number | null {
+  if (typeof value !== "string") return null;
+  const parsedTs = Date.parse(value);
+  if (!Number.isFinite(parsedTs)) return null;
+  const waitMs = parsedTs - Date.now();
+  return waitMs > 0 ? Math.min(waitMs, maxMs) : null;
+}
+
+/**
+ * Parse Retry-After hints from a 429 JSON response body. Providers use both
+ * top-level and nested `error` fields for ISO timestamps and millisecond values.
+ */
+export function parseRetryHintFromJsonBody(body: string, maxMs: number): number | null {
+  let parsed: unknown;
+  try {
+    parsed = JSON.parse(body);
+  } catch {
+    return null;
+  }
+
+  const root = objectRecord(parsed);
+  if (!Object.keys(root).length) return null;
+  const errorObj = objectRecord(root.error);
+
+  const isoHint = futureTimestampMs(errorObj.retryAfter ?? root.retryAfter, maxMs);
+  if (isoHint !== null) return isoHint;
+
+  return positiveCappedMs(
+    errorObj.retry_after_ms ?? root.retry_after_ms ?? errorObj.retryAfterMs ?? root.retryAfterMs,
+    maxMs
+  );
+}
diff --git a/tests/unit/account-fallback-retry-after-json.test.ts b/tests/unit/account-fallback-retry-after-json.test.ts
new file mode 100644
index 0000000000..515dd46351
--- /dev/null
+++ b/tests/unit/account-fallback-retry-after-json.test.ts
@@ -0,0 +1,32 @@
+import test from "node:test";
+import assert from "node:assert/strict";
+
+const { parseRetryFromErrorText } = await import("../../open-sse/services/accountFallback.ts");
+
+test("parseRetryFromErrorText reads nested ISO retryAfter from a 429 JSON body", () => {
+  const futureIso = new Date(Date.now() + 120_000).toISOString();
+  const waitMs = parseRetryFromErrorText(JSON.stringify({ error: { retryAfter: futureIso } }));
+  assert.ok(waitMs !== null, "expected a parsed wait time, got null");
+  assert.ok(Math.abs((waitMs as number) - 120_000) <= 2_000, `expected ~120000ms, got ${waitMs}`);
+});
+
+test("parseRetryFromErrorText reads top-level retryAfter when nested field is absent", () => {
+  const futureIso = new Date(Date.now() + 60_000).toISOString();
+  const waitMs = parseRetryFromErrorText(JSON.stringify({ retryAfter: futureIso }));
+  assert.ok(waitMs !== null, "expected a parsed wait time, got null");
+  assert.ok(Math.abs((waitMs as number) - 60_000) <= 2_000, `expected ~60000ms, got ${waitMs}`);
+});
+
+test("parseRetryFromErrorText reads millisecond retry hints from 429 JSON bodies", () => {
+  assert.equal(parseRetryFromErrorText(JSON.stringify({ retry_after_ms: 45_000 })), 45_000);
+  assert.equal(
+    parseRetryFromErrorText(JSON.stringify({ error: { retry_after_ms: 12_000 } })),
+    12_000
+  );
+  assert.equal(parseRetryFromErrorText(JSON.stringify({ retryAfterMs: 8_000 })), 8_000);
+});
+
+test("parseRetryFromErrorText ignores past ISO retryAfter values in JSON bodies", () => {
+  const pastIso = new Date(Date.now() - 60_000).toISOString();
+  assert.equal(parseRetryFromErrorText(JSON.stringify({ error: { retryAfter: pastIso } })), null);
+});