[docs][evaluation] fix stale doc comment & clarify retry semantics

- ValidateOpenAPIEvalTargetClusterEnv doc comment matched the pre-narrowing
  behavior (claimed to validate a2a/custom_rpc); correct it to reflect that
  only custom_agent is validated now.
- record_data.go: note that the upload retry currently retries ALL errors
  indiscriminately (no transient/permanent distinction); suggest
  backoff.Permanent for non-transient errors if an error-code set is known later.

Comment-only, no behavior change.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: xueyizheng

backend/modules/evaluation/application/convertor/experiment/openapi.go

@@ -248,15 +248,16 @@ func IsSupportedOpenAPIEvalTargetType(t openapiEvalTarget.EvalTargetType) bool {
 	return err == nil
 }
 
-// ValidateOpenAPIEvalTargetClusterEnv validates the required cluster/env for
-// long-connection eval targets (custom_agent / a2a_agent / custom_rpc_server).
-// These are resolved to a live RPC/frontier client at run time, so a missing
-// cluster/env passes creation silently and only fails later with an opaque RPC
-// error. Rejecting it up front yields a clear param error with common values.
-//   - custom_agent / a2a_agent: both cluster and env are caller-supplied → required.
-//   - custom_rpc_server: cluster comes from the app config, only env is required.
+// ValidateOpenAPIEvalTargetClusterEnv validates the required cluster/env for the
+// long-connection custom_agent eval target. custom_agent is resolved to a live
+// RPC/frontier client at run time, so a missing cluster/env passes creation
+// silently and only fails later with an opaque RPC error; rejecting it up front
+// yields a clear param error with common values.
+//   - custom_agent: cluster and env are required, UNLESS an explicit AgentConnection
+//     (frontier direct-connect) is provided — direct-connect does not use cluster/env.
+//   - a2a_agent / custom_rpc_server: intentionally NOT validated for now.
 //
-// Returns nil when param/type is nil or the type is not a long-connection target.
+// Returns nil when param/type is nil or the type is not custom_agent.
 func ValidateOpenAPIEvalTargetClusterEnv(param *openapi.SubmitExperimentEvalTargetParam) error {
 	if param == nil || param.EvalTargetType == nil {
 		return nil

backend/modules/evaluation/infra/storage/record_data.go

@@ -247,6 +247,8 @@ func (s *RecordDataStorage) processContent(ctx context.Context, content *entity.
 	key := EvalRecordFieldKeyPrefix + uuid.New().String()
 	// ImageX/对象存储偶发单实例迁移会返回临时错误（如 201007 / bad gateway），系统会自动迁移恢复，重试即可成功。
 	// 这里做固定间隔的止血重试：最多 2 次重试（共 3 次尝试）、间隔 1.5s；每轮都重建 reader，避免上一轮已消费导致重传空内容。
+	// 注意：当前对所有 error 无差别重试，未区分瞬时/永久错误——权限、参数非法等确定性失败也会重试满 3 次（额外等 ~3s）后才返回。
+	// 若后续拿到可重试错误码集合，可在闭包内对非瞬时错误用 backoff.Permanent(err) 短路。
 	data := []byte(text)
 	if err := backoff.RetryWithMaxTimesAndInterval(ctx, 2, 1500*time.Millisecond, func() error {
 		return s.batchStorage.Upload(ctx, key, bytes.NewReader(data))