diff --git a/apps/daemon/src/run-failure-classification.ts b/apps/daemon/src/run-failure-classification.ts
index dd833aa7ebe..629ecdbb7e6 100644
--- a/apps/daemon/src/run-failure-classification.ts
+++ b/apps/daemon/src/run-failure-classification.ts
@@ -128,7 +128,7 @@ function inferFailureStageFromEvents(
   return fallback;
 }
 
-function collectFailureText(input: RunFailureClassificationInput): string {
+function collectFailureParts(input: RunFailureClassificationInput): string[] {
   const parts: string[] = [];
   const statusError = readString(input.status.error);
   if (statusError) parts.push(statusError);
@@ -143,12 +143,56 @@ function collectFailureText(input: RunFailureClassificationInput): string {
       parts.push(...eventStderrText(rec.data));
     }
   }
-  return parts.join('\n');
+  return parts;
 }
 
-function isHardQuotaText(text: string): boolean {
-  return /\b(session limit|usage limit|limit reached|quota|billing (?:hard )?limit|insufficient[ _-]?(?:quota|credit|credits|funds)|exceeded your current quota|out of credits|no payment method|requires more credits|can only afford)\b|DAILY_LIMIT_EXCEEDED|用户额度不足|额度不足|预扣费额度失败/i
-    .test(text);
+function collectFailureText(input: RunFailureClassificationInput): string {
+  return collectFailureParts(input).join('\n');
+}
+
+// A bare `quota` alternative used to live in the alternation below, which made
+// this matcher fire on our *own* generic empty-output fallback (server.ts:
+// "...then try re-authenticating the agent, checking quota, or switching
+// models."). The quota branch is evaluated before `isEmptyOutputText`, so every
+// output-less run — for any reason — was reported as an exhausted quota, and
+// run-retry-policy suppresses retries outright on `hard_quota`. That is the
+// misclassification behind #6143: third-party API runs failed permanently while
+// the provider still had quota.
+//
+// So `quota` on its own is not a signal; it needs a corroborating word. This
+// mirrors the detector that already got it right —
+// integrations/vela-errors.ts requires one of wallet/balance/credit/billing/funds
+// alongside `quota`. Phrases that are unambiguous on their own (session limit,
+// insufficient quota, exceeded your current quota…) keep matching directly.
+//
+// Evaluated per collected fragment, never over the joined text. `collectFailureText`
+// concatenates up to 24 unrelated messages with '\n', so whole-text corroboration
+// would let *any* fragment mentioning a plan or payment vouch for a bare `quota`
+// sitting in a different one — which is precisely how the empty-output fallback
+// would find its way back to `hard_quota`. Fragment scope also keeps the `\s+`
+// in the adjacency patterns below from bridging two messages across the join.
+function isHardQuotaFragment(text: string): boolean {
+  if (/\b(session limit|usage limit|limit reached|billing (?:hard )?limit|insufficient[ _-]?(?:quota|credit|credits|funds)|exceeded your current quota|out of credits|no payment method|requires more credits|can only afford)\b|DAILY_LIMIT_EXCEEDED|用户额度不足|额度不足|预扣费额度失败/i
+    .test(text)) {
+    return true;
+  }
+  // `quota` next to an exhaustion word is unambiguous on its own — no wallet or
+  // balance needed. `quota exhausted` is a real upstream payload in this repo
+  // (tests/byok-tools.test.ts: `status_msg: 'quota exhausted'`); requiring
+  // corroboration for it would turn a terminal failure into a retry candidate
+  // (and under RATE_LIMITED, a retryable `rate_limit_429`), which is the exact
+  // inverse of the misclassification this function is being fixed for.
+  if (/\bquota\s+(?:exceeded|exhausted|depleted|reached|used\s+up)\b/i.test(text)
+    || /\b(?:exceeded|exhausted|out\s+of|ran\s+out\s+of|no\s+remaining)\s+(?:\w+\s+){0,3}quota\b/i
+      .test(text)) {
+    return true;
+  }
+  return /\bquota\b/i.test(text) &&
+    /\b(wallet|balance|credits?|billing|funds?|payment|plan)\b/i.test(text);
+}
+
+function isHardQuotaText(parts: string[]): boolean {
+  return parts.some(isHardQuotaFragment);
 }
 
 // A transient, retryable rate limit (distinct from a hard quota). vela/upstream
@@ -636,7 +680,8 @@ export function classifyRunFailure(
   }
 
   const errorCode = normalizeCode(input.errorCode ?? input.status.errorCode);
-  const text = collectFailureText(input);
+  const parts = collectFailureParts(input);
+  const text = parts.join('\n');
   const retryableHint = latestRetryable(input.events);
   const amrFailure = classifyAmrAccountFailure(text);
   const byokOpenCodeProviderNotFound = isByokOpenCodeProviderNotFoundText(
@@ -810,8 +855,8 @@ export function classifyRunFailure(
     );
   }
 
-  if (errorCode === 'RATE_LIMITED' || serviceFailure === 'RATE_LIMITED' || isHardQuotaText(text) || isRateLimitText(text)) {
-    const hardQuota = isHardQuotaText(text);
+  const hardQuota = isHardQuotaText(parts);
+  if (errorCode === 'RATE_LIMITED' || serviceFailure === 'RATE_LIMITED' || hardQuota || isRateLimitText(text)) {
     const workspaceCredits = isWorkspaceCreditsText(text);
     const retryable = hardQuota ? false : (retryableHint ?? true);
     return classification(
diff --git a/apps/daemon/tests/run-failure-classification.test.ts b/apps/daemon/tests/run-failure-classification.test.ts
index 86a20bae2c6..8af837b2226 100644
--- a/apps/daemon/tests/run-failure-classification.test.ts
+++ b/apps/daemon/tests/run-failure-classification.test.ts
@@ -333,6 +333,125 @@ describe('classifyRunFailure', () => {
     });
   });
 
+  // Refs #6143. The daemon's own generic empty-output fallback (server.ts) ends
+  // with "...then try re-authenticating the agent, checking quota, or switching
+  // models." `isHardQuotaText` used to carry a bare `quota` alternative, so the
+  // daemon read its own message back and concluded the user was out of quota.
+  //
+  // That is not cosmetic: run-retry-policy suppresses retries outright on
+  // `hard_quota`, which is why the reporter saw every third-party-API run fail
+  // permanently while the provider itself had quota left.
+  const EMPTY_OUTPUT_FALLBACK =
+    'Agent completed without producing any output. The model or provider may ' +
+    'have returned an empty response. Check the agent logs for upstream ' +
+    'errors, then try re-authenticating the agent, checking quota, or ' +
+    'switching models.';
+
+  it('does not read its own empty-output fallback as a hard quota', () => {
+    expect(classify('AGENT_EXECUTION_FAILED', EMPTY_OUTPUT_FALLBACK)).toMatchObject({
+      failure_category: 'empty_output',
+      failure_detail: 'empty_output',
+    });
+  });
+
+  it('does not let an unrelated fragment corroborate the fallback back into a hard quota', () => {
+    // `collectFailureText` joins up to 24 unrelated messages with '\n'. If the
+    // corroboration rule is applied to that joined string, any *other* fragment
+    // mentioning a plan or a payment vouches for the bare `quota` sitting in the
+    // empty-output fallback — and the run is suppressed from retrying again.
+    // Corroboration has to hold within a single collected fragment.
+    for (const unrelated of [
+      'Switched to the fallback plan for this workspace.',
+      'Your payment details were updated 3 days ago.',
+      'Restored session from the previous billing period snapshot.',
+    ]) {
+      expect(
+        classify('AGENT_EXECUTION_FAILED', EMPTY_OUTPUT_FALLBACK, [
+          errorEvent('AGENT_EXECUTION_FAILED', EMPTY_OUTPUT_FALLBACK),
+          errorEvent('AGENT_EXECUTION_FAILED', unrelated),
+        ]),
+        unrelated,
+      ).toMatchObject({
+        failure_category: 'empty_output',
+        failure_detail: 'empty_output',
+      });
+    }
+
+    // Same boundary for the exhaustion collocations: `\s+` matches the '\n' the
+    // fragments are joined with, so a message ending in `quota` must not pair up
+    // with the next message starting in `exceeded`.
+    expect(
+      classify('AGENT_EXECUTION_FAILED', EMPTY_OUTPUT_FALLBACK, [
+        errorEvent('AGENT_EXECUTION_FAILED', 'Reported usage against the quota'),
+        errorEvent('AGENT_EXECUTION_FAILED', 'exceeded the configured step budget'),
+      ]),
+    ).toMatchObject({
+      failure_category: 'empty_output',
+      failure_detail: 'empty_output',
+    });
+
+    // …while a fragment that corroborates *itself* still classifies, even when
+    // it arrives alongside the fallback.
+    expect(
+      classify('AGENT_EXECUTION_FAILED', EMPTY_OUTPUT_FALLBACK, [
+        errorEvent('AGENT_EXECUTION_FAILED', EMPTY_OUTPUT_FALLBACK),
+        errorEvent(
+          'AGENT_EXECUTION_FAILED',
+          'You exceeded your current quota, please check your plan and billing details.',
+        ),
+      ]),
+    ).toMatchObject({
+      failure_category: 'rate_limit',
+      failure_detail: 'hard_quota',
+      retryable: false,
+    });
+  });
+
+  it('still treats a real quota exhaustion as a hard quota', () => {
+    // The word `quota` alone must not be the trigger, but a corroborated quota
+    // message still has to classify — otherwise this fix trades one silent
+    // misclassification for another.
+    for (const text of [
+      'You exceeded your current quota, please check your plan and billing details.',
+      'Insufficient quota for the current billing period.',
+    ]) {
+      expect(classify('AGENT_EXECUTION_FAILED', text), text).toMatchObject({
+        failure_category: 'rate_limit',
+        failure_detail: 'hard_quota',
+        retryable: false,
+      });
+    }
+    // Explicit exhaustion collocations must survive the corroboration rule.
+    // `quota exhausted` is a real upstream payload in this repo
+    // (tests/byok-tools.test.ts: `status_msg: 'quota exhausted'`), and dropping
+    // it would turn a terminal quota failure into a retry candidate — the exact
+    // inverse of the bug this PR fixes.
+    for (const text of [
+      'quota exhausted',
+      'quota exceeded',
+      'Quota depleted for this account.',
+      'You have exceeded your monthly quota.',
+      'HTTP 429: out of quota',
+    ]) {
+      expect(classify('AGENT_EXECUTION_FAILED', text), text).toMatchObject({
+        failure_detail: 'hard_quota',
+        retryable: false,
+      });
+      // With RATE_LIMITED the stakes are higher: without the phrase match this
+      // becomes a retryable rate_limit_429 and the suppression contract breaks.
+      expect(classify('RATE_LIMITED', text), `RATE_LIMITED ${text}`).toMatchObject({
+        failure_detail: 'hard_quota',
+        retryable: false,
+      });
+    }
+    // The Chinese vela pre-charge text has its own, more specific detail and
+    // must keep it — it is routed before the quota branch.
+    expect(classify('AGENT_EXECUTION_FAILED', '用户额度不足')).toMatchObject({
+      failure_detail: 'amr_insufficient_balance',
+      retryable: false,
+    });
+  });
+
   it('maps upstream failures to retry guidance', () => {
     expect(classify('UPSTREAM_UNAVAILABLE', 'HTTP 503 upstream unavailable')).toMatchObject({
       failure_category: 'upstream_unavailable',