diff --git a/internal/auth/codex/openai_auth.go b/internal/auth/codex/openai_auth.go
index c273acae..64bc00a6 100644
--- a/internal/auth/codex/openai_auth.go
+++ b/internal/auth/codex/openai_auth.go
@@ -276,6 +276,10 @@ func (o *CodexAuth) RefreshTokensWithRetry(ctx context.Context, refreshToken str
 		if err == nil {
 			return tokenData, nil
 		}
+		if isNonRetryableRefreshErr(err) {
+			log.Warnf("Token refresh attempt %d failed with non-retryable error: %v", attempt+1, err)
+			return nil, err
+		}
 
 		lastErr = err
 		log.Warnf("Token refresh attempt %d failed: %v", attempt+1, err)
@@ -284,6 +288,14 @@ func (o *CodexAuth) RefreshTokensWithRetry(ctx context.Context, refreshToken str
 	return nil, fmt.Errorf("token refresh failed after %d attempts: %w", maxRetries, lastErr)
 }
 
+func isNonRetryableRefreshErr(err error) bool {
+	if err == nil {
+		return false
+	}
+	raw := strings.ToLower(err.Error())
+	return strings.Contains(raw, "refresh_token_reused")
+}
+
 // UpdateTokenStorage updates an existing CodexTokenStorage with new token data.
 // This is typically called after a successful token refresh to persist the new credentials.
 func (o *CodexAuth) UpdateTokenStorage(storage *CodexTokenStorage, tokenData *CodexTokenData) {
diff --git a/internal/auth/codex/openai_auth_test.go b/internal/auth/codex/openai_auth_test.go
new file mode 100644
index 00000000..3327eb4a
--- /dev/null
+++ b/internal/auth/codex/openai_auth_test.go
@@ -0,0 +1,44 @@
+package codex
+
+import (
+	"context"
+	"io"
+	"net/http"
+	"strings"
+	"sync/atomic"
+	"testing"
+)
+
+type roundTripFunc func(*http.Request) (*http.Response, error)
+
+func (f roundTripFunc) RoundTrip(req *http.Request) (*http.Response, error) {
+	return f(req)
+}
+
+func TestRefreshTokensWithRetry_NonRetryableOnlyAttemptsOnce(t *testing.T) {
+	var calls int32
+	auth := &CodexAuth{
+		httpClient: &http.Client{
+			Transport: roundTripFunc(func(req *http.Request) (*http.Response, error) {
+				atomic.AddInt32(&calls, 1)
+				return &http.Response{
+					StatusCode: http.StatusBadRequest,
+					Body:       io.NopCloser(strings.NewReader(`{"error":"invalid_grant","code":"refresh_token_reused"}`)),
+					Header:     make(http.Header),
+					Request:    req,
+				}, nil
+			}),
+		},
+	}
+
+	_, err := auth.RefreshTokensWithRetry(context.Background(), "dummy_refresh_token", 3)
+	if err == nil {
+		t.Fatalf("expected error for non-retryable refresh failure")
+	}
+	if !strings.Contains(strings.ToLower(err.Error()), "refresh_token_reused") {
+		t.Fatalf("expected refresh_token_reused in error, got: %v", err)
+	}
+	if got := atomic.LoadInt32(&calls); got != 1 {
+		t.Fatalf("expected 1 refresh attempt, got %d", got)
+	}
+}