diff --git a/admin/app/controllers/benchmark_controller.ts b/admin/app/controllers/benchmark_controller.ts
index 144bb54c..714c61a8 100644
--- a/admin/app/controllers/benchmark_controller.ts
+++ b/admin/app/controllers/benchmark_controller.ts
@@ -184,9 +184,22 @@ export default class BenchmarkController {
       // Pass through the status code from the service if available, otherwise default to 400
       const statusCode = (error as any).statusCode || 400
       logger.error({ err: error }, '[BenchmarkController] Benchmark submit failed')
+
+      // Surface a clear, actionable reason to the UI instead of a generic failure.
+      // The rate limiter (429) is the most common cause, so name it explicitly;
+      // otherwise pass through the underlying detail (repository error or a service
+      // validation message) and fall back to a safe generic only when we have none.
+      let errorMessage: string
+      if (statusCode === 429) {
+        errorMessage = 'You can only submit one benchmark per hour. Please wait a bit and try again.'
+      } else {
+        errorMessage =
+          (error as any).detail || (error as any).message || 'Failed to submit benchmark results.'
+      }
+
       return response.status(statusCode).send({
         success: false,
-        error: 'Failed to submit benchmark results.',
+        error: errorMessage,
       })
     }
   }
diff --git a/admin/app/services/benchmark_service.ts b/admin/app/services/benchmark_service.ts
index 03d1f1b9..0a6239ae 100644
--- a/admin/app/services/benchmark_service.ts
+++ b/admin/app/services/benchmark_service.ts
@@ -299,9 +299,11 @@ export class BenchmarkService {
       const statusCode = error.response?.status
       logger.error(`Failed to submit benchmark to repository: ${detail} (Status: ${statusCode})`)
       
-      // Create an error with the status code attached for proper handling upstream
+      // Create an error with the status code and raw detail attached for proper
+      // handling upstream (the controller surfaces `detail` as the user-facing reason).
       const err: any = new Error(`Failed to submit benchmark: ${detail}`)
       err.statusCode = statusCode
+      err.detail = detail
       throw err
     }
   }