diff --git a/open-sse/config/providerErrorRules.ts b/open-sse/config/providerErrorRules.ts
index 15e82adf4e..ae2f495573 100644
--- a/open-sse/config/providerErrorRules.ts
+++ b/open-sse/config/providerErrorRules.ts
@@ -180,7 +180,13 @@ function buildOpenrouterRules(): ProviderErrorRule[] {
 // agentrouter.org misstates temporary quota exhaustion as 403/400 with a
 // Chinese body. upstreamStatusRestatement.ts rewrites the status to 429
 // BEFORE classification, so rules here accept both the raw 403/400 and the
-// restated 429 (text is the real discriminator either way).
+// restated 429 (text is the real discriminator either way). In production,
+// the raw 403 path is what actually matters here: checkFallbackError's
+// apikey-category FORBIDDEN branch (~line 1699) returns EARLY for a plain
+// 403, before these rules are ever consulted — these rules fire on the
+// RESTATED 429 (chatCore's upstreamStatusRestatement hook runs first) via
+// resolveRuleMatchBody, which is the only path in checkFallbackError that
+// hands these rules the full error text instead of just {code, type}.
 //  - "额度不足": account-wide temporary quota → quota_exhausted, scope
 //    "connection" (mirror of the Opencode account-wide rationale above).
 //  - "无权访问模型": this key permanently lacks access to ONE model → lock only
@@ -227,6 +233,34 @@ export const providerRuleRegistry = new Map<string, ProviderErrorRule[]>([
   ["agentrouter", buildAgentrouterRules()],
 ]);
 
+/**
+ * Providers whose rules match on the FULL upstream error text.
+ * checkFallbackError's rule lookup normally passes only the structured
+ * error ({code, type} — message stripped by the combo callers), which is
+ * enough for header/status/code rules but blind to body-text markers like
+ * agentrouter's "额度不足". Providers in this set get the raw error text as
+ * the match body instead. EXCLUSIVE allowlist by owner decision (2026-08-13):
+ * adding a provider here is an explicit opt-in — the default path for every
+ * other provider must remain byte-for-byte unchanged.
+ */
+const FULL_TEXT_RULE_PROVIDERS = new Set(["agentrouter"]);
+
+/**
+ * Resolve the body handed to getProviderErrorRuleMatch inside
+ * checkFallbackError: full error text for FULL_TEXT_RULE_PROVIDERS,
+ * the structured error for everyone else.
+ */
+export function resolveRuleMatchBody(
+  provider: string | null | undefined,
+  structuredError: unknown,
+  errorText: string | null | undefined
+): unknown {
+  if (provider && FULL_TEXT_RULE_PROVIDERS.has(provider.toLowerCase()) && errorText) {
+    return errorText;
+  }
+  return structuredError ?? null;
+}
+
 /**
  * Returns the first matching rule for a provider, or null if none match.
  * Callers use this to (a) classify the reason and (b) decide whether to
diff --git a/open-sse/services/accountFallback.ts b/open-sse/services/accountFallback.ts
index d8175272c9..0f2c43a28f 100644
--- a/open-sse/services/accountFallback.ts
+++ b/open-sse/services/accountFallback.ts
@@ -14,7 +14,7 @@ import {
   serviceSupervisorCooldown,
   isNimFunctionDegraded,
 } from "../config/errorConfig.ts";
-import { getProviderErrorRuleMatch } from "../config/providerErrorRules.ts";
+import { getProviderErrorRuleMatch, resolveRuleMatchBody } from "../config/providerErrorRules.ts";
 import * as rot from "./rotationConfig.ts";
 import { getPassthroughProviders, getProviderCategory } from "../config/providerRegistry.ts";
 import {
@@ -1727,7 +1727,12 @@ export function checkFallbackError(
       // specific configured reasons (e.g. 503 → SERVER_ERROR would be
       // shadowed by 503 → MODEL_CAPACITY).
       const providerMatch = provider
-        ? getProviderErrorRuleMatch(provider, status, headers, structuredError ?? null)
+        ? getProviderErrorRuleMatch(
+            provider,
+            status,
+            headers,
+            resolveRuleMatchBody(provider, structuredError ?? null, errorStr)
+          )
         : null;
       const reason = providerMatch
         ? providerMatch.reason
@@ -1760,7 +1765,12 @@ export function checkFallbackError(
     // generic zero-cooldown default. Mirror the backoff branch above so
     // provider rules win on cooldown/reason regardless of `backoff`.
     const providerMatch = provider
-      ? getProviderErrorRuleMatch(provider, status, headers, structuredError ?? null)
+      ? getProviderErrorRuleMatch(
+          provider,
+          status,
+          headers,
+          resolveRuleMatchBody(provider, structuredError ?? null, errorStr)
+        )
       : null;
     const cooldownMs = providerMatch?.cooldownMs ?? configuredRule.cooldownMs ?? 0;
     return {
diff --git a/tests/unit/agentrouter-error-rules.test.ts b/tests/unit/agentrouter-error-rules.test.ts
index 0923f3e83d..d9cecd78fd 100644
--- a/tests/unit/agentrouter-error-rules.test.ts
+++ b/tests/unit/agentrouter-error-rules.test.ts
@@ -58,15 +58,29 @@ test("A5: classifyError integration — quota text wins over the 403→AUTH_ERRO
   assert.equal(reason, RateLimitReason.QUOTA_EXHAUSTED);
 });
 
-test("A6: guard — restated quota error is retryable, never terminal", () => {
+test("A6: guard — restated quota error is retryable, never terminal, and now actually classified as quota_exhausted", () => {
+  // Status 429 (post-restatement) reaches checkFallbackError's provider-rule
+  // lookup. resolveRuleMatchBody() hands agentrouter the full error text
+  // (instead of just the stripped {code, type} structuredError every other
+  // provider gets), so the "额度不足" rule actually fires here — this is the
+  // production path the restatement hook (Task 2) feeds into.
   const result = checkFallbackError(429, "用户额度不足", 0, null, "agentrouter", null);
   assert.equal(result.shouldFallback, true);
+  assert.equal(result.reason, "quota_exhausted");
   assert.ok(!result.permanent, "quota misstatus must never be permanent");
   assert.ok(!result.creditsExhausted, "must not trip CREDITS_EXHAUSTED_SIGNALS");
   assert.ok(result.cooldownMs > 0, "must carry a real cooldown");
 });
 
 test("A7: guard — raw 403 quota (hook bypassed) is still not account-deactivation", () => {
+  // A raw (pre-restatement) 403 never actually reaches the agentrouter provider
+  // rules in production: checkFallbackError's apikey-category FORBIDDEN branch
+  // (status === 403 && getProviderCategory(provider) === "apikey") returns
+  // EARLY via resolveApiKeyForbiddenFallback before the provider-rule lookup
+  // is ever consulted. In the real pipeline, chatCore's upstreamStatusRestatement
+  // hook (Task 2) already converts 403→429 before checkFallbackError ever sees
+  // it, so this early-return path is what a hook-bypassed raw 403 hits — and it
+  // must still not be misclassified as permanent account deactivation.
   const result = checkFallbackError(403, "用户额度不足", 0, null, "agentrouter", null);
   assert.equal(result.shouldFallback, true);
   assert.ok(!result.permanent);
@@ -76,3 +90,39 @@ test("A8: plain agentrouter 403 (no quota text) keeps the default apikey auth pa
   const match = getProviderErrorRuleMatch("agentrouter", 403, {}, "Invalid API key");
   assert.equal(match, null);
 });
+
+test("A9: resolveRuleMatchBody hands full text ONLY to allowlisted providers", async () => {
+  const { resolveRuleMatchBody } = await import(
+    "../../open-sse/config/providerErrorRules.ts"
+  );
+  const structured = { code: "rate_limited", type: "requests" };
+  assert.equal(resolveRuleMatchBody("agentrouter", structured, "用户额度不足"), "用户额度不足");
+  assert.equal(resolveRuleMatchBody("opencode", structured, "monthly usage limit reached"), structured);
+  assert.equal(resolveRuleMatchBody("openrouter", null, "some error text"), null);
+  assert.equal(resolveRuleMatchBody("agentrouter", structured, ""), structured);
+});
+
+test("A10: other providers' checkFallbackError behavior is unchanged (exclusivity)", () => {
+  // opencode's body-text rule ("organization_quota_exceeded") must still NOT
+  // fire through checkFallbackError — the allowlist is agentrouter-only, so
+  // opencode keeps getting only the stripped structuredError as the match
+  // body (null here, since no structuredError arg is passed), same as before
+  // this fix. Baseline captured on the pre-fix code with this exact input:
+  //   { shouldFallback: true, cooldownMs: 3000, baseCooldownMs: 3000,
+  //     newBackoffLevel: 1, usedUpstreamRetryHint: false,
+  //     reason: "rate_limit_exceeded" }
+  // i.e. it falls through to the generic 429 configured rule, NOT the
+  // opencode-quota-exhausted-body provider rule — asserting `reason` here is
+  // exactly what proves the allowlist didn't leak to opencode.
+  const result = checkFallbackError(
+    429,
+    '{"error":{"message":"organization_quota_exceeded"}}',
+    0,
+    null,
+    "opencode",
+    null
+  );
+  assert.ok(result.shouldFallback);
+  assert.equal(result.reason, "rate_limit_exceeded");
+  assert.equal(result.cooldownMs, 3000);
+});