**refactor(executor): simplify Gemini CLI execution and remove internal retry logic**

- Removed nested retry handling for 429 rate limit errors.
- Simplified request/response handling by cleaning redundant retry-related code.
- Eliminated `parseRetryDelay` function and max retry configuration logic.

sdk/cliproxy/auth/manager.go

@@ -62,6 +62,8 @@ type Result struct {
 	Model string
 	// Success marks whether the execution succeeded.
 	Success bool
+	// RetryAfter carries a provider supplied retry hint (e.g. 429 retryDelay).
+	RetryAfter *time.Duration
 	// Error describes the failure when Success is false.
 	Error *Error
 }
@@ -325,6 +327,9 @@ func (m *Manager) executeWithProvider(ctx context.Context, provider string, req
 			if errors.As(errExec, &se) && se != nil {
 				result.Error.HTTPStatus = se.StatusCode()
 			}
+			if ra := retryAfterFromError(errExec); ra != nil {
+				result.RetryAfter = ra
+			}
 			m.MarkResult(execCtx, result)
 			lastErr = errExec
 			continue
@@ -370,6 +375,9 @@ func (m *Manager) executeCountWithProvider(ctx context.Context, provider string,
 			if errors.As(errExec, &se) && se != nil {
 				result.Error.HTTPStatus = se.StatusCode()
 			}
+			if ra := retryAfterFromError(errExec); ra != nil {
+				result.RetryAfter = ra
+			}
 			m.MarkResult(execCtx, result)
 			lastErr = errExec
 			continue
@@ -415,6 +423,7 @@ func (m *Manager) executeStreamWithProvider(ctx context.Context, provider string
 				rerr.HTTPStatus = se.StatusCode()
 			}
 			result := Result{AuthID: auth.ID, Provider: provider, Model: req.Model, Success: false, Error: rerr}
+			result.RetryAfter = retryAfterFromError(errStream)
 			m.MarkResult(execCtx, result)
 			lastErr = errStream
 			continue
@@ -556,17 +565,23 @@ func (m *Manager) MarkResult(ctx context.Context, result Result) {
 					suspendReason = "payment_required"
 					shouldSuspendModel = true
 				case 429:
-					cooldown, nextLevel := nextQuotaCooldown(state.Quota.BackoffLevel)
 					var next time.Time
-					if cooldown > 0 {
-						next = now.Add(cooldown)
+					backoffLevel := state.Quota.BackoffLevel
+					if result.RetryAfter != nil {
+						next = now.Add(*result.RetryAfter)
+					} else {
+						cooldown, nextLevel := nextQuotaCooldown(backoffLevel)
+						if cooldown > 0 {
+							next = now.Add(cooldown)
+						}
+						backoffLevel = nextLevel
 					}
 					state.NextRetryAfter = next
 					state.Quota = QuotaState{
 						Exceeded:      true,
 						Reason:        "quota",
 						NextRecoverAt: next,
-						BackoffLevel:  nextLevel,
+						BackoffLevel:  backoffLevel,
 					}
 					suspendReason = "quota"
 					shouldSuspendModel = true
@@ -582,7 +597,7 @@ func (m *Manager) MarkResult(ctx context.Context, result Result) {
 				auth.UpdatedAt = now
 				updateAggregatedAvailability(auth, now)
 			} else {
-				applyAuthFailureState(auth, result.Error, now)
+				applyAuthFailureState(auth, result.Error, result.RetryAfter, now)
 			}
 		}
 
@@ -742,6 +757,25 @@ func cloneError(err *Error) *Error {
 	}
 }
 
+func retryAfterFromError(err error) *time.Duration {
+	if err == nil {
+		return nil
+	}
+	type retryAfterProvider interface {
+		RetryAfter() *time.Duration
+	}
+	rap, ok := err.(retryAfterProvider)
+	if !ok || rap == nil {
+		return nil
+	}
+	retryAfter := rap.RetryAfter()
+	if retryAfter == nil {
+		return nil
+	}
+	val := *retryAfter
+	return &val
+}
+
 func statusCodeFromResult(err *Error) int {
 	if err == nil {
 		return 0
@@ -749,7 +783,7 @@ func statusCodeFromResult(err *Error) int {
 	return err.StatusCode()
 }
 
-func applyAuthFailureState(auth *Auth, resultErr *Error, now time.Time) {
+func applyAuthFailureState(auth *Auth, resultErr *Error, retryAfter *time.Duration, now time.Time) {
 	if auth == nil {
 		return
 	}
@@ -774,13 +808,17 @@ func applyAuthFailureState(auth *Auth, resultErr *Error, now time.Time) {
 		auth.StatusMessage = "quota exhausted"
 		auth.Quota.Exceeded = true
 		auth.Quota.Reason = "quota"
-		cooldown, nextLevel := nextQuotaCooldown(auth.Quota.BackoffLevel)
 		var next time.Time
-		if cooldown > 0 {
-			next = now.Add(cooldown)
+		if retryAfter != nil {
+			next = now.Add(*retryAfter)
+		} else {
+			cooldown, nextLevel := nextQuotaCooldown(auth.Quota.BackoffLevel)
+			if cooldown > 0 {
+				next = now.Add(cooldown)
+			}
+			auth.Quota.BackoffLevel = nextLevel
 		}
 		auth.Quota.NextRecoverAt = next
-		auth.Quota.BackoffLevel = nextLevel
 		auth.NextRetryAfter = next
 	case 408, 500, 502, 503, 504:
 		auth.StatusMessage = "transient upstream error"