diff --git a/rag/flow/hierarchical_merger/schema.py b/rag/flow/hierarchical_merger/schema.py
index a4d99f914..65c2ffaa0 100644
--- a/rag/flow/hierarchical_merger/schema.py
+++ b/rag/flow/hierarchical_merger/schema.py
@@ -25,7 +25,7 @@ class HierarchicalMergerFromUpstream(BaseModel):
     file: dict | None = Field(default=None)
     chunks: list[dict[str, Any]] | None = Field(default=None)
 
-    output_format: Literal["json", "chunks"] | None = Field(default=None)
+    output_format: Literal["json", "markdown", "text", "html", "chunks"] | None = Field(default=None)
     json_result: list[dict[str, Any]] | None = Field(default=None, alias="json")
     markdown_result: str | None = Field(default=None, alias="markdown")
     text_result: str | None = Field(default=None, alias="text")