revert(cli): default to NaiveReranker

Author: Zhe Yu

docs/cli.md

@@ -311,16 +311,11 @@ The JSON configuration file may hold the following values:
   guarantees the return of `n` documents, but with the risk of including too
   many less-relevant chunks that may affect the document selection. Default: 
   `-1` (any negative value means selecting documents based on all indexed chunks);
-- `reranker`: string, the reranking method to use. Currently supports
-  `CrossEncoderReranker` (default, using 
+- `reranker`: string, the reranking method to use. Currently supports `NaiveReranker` 
+  (sort chunks by the "distance" between the embedding vectors) and 
+  `CrossEncoderReranker` (using 
   [sentence-transformers cross-encoder](https://sbert.net/docs/package_reference/cross_encoder/cross_encoder.html)
-  ) and `NaiveReranker` (sort chunks by the "distance" between the embedding
-  vectors).
-  Note: If you're using a good embedding model (eg. a hosted service from OpenAI, or 
-  a LLM-based embedding model like 
-  [Qwen3-Embedding-0.6B](https://huggingface.co/Qwen/Qwen3-Embedding-0.6B)), you
-  may get better results if you use `NaiveReranker` here because a good embedding
-  model may understand texts better than a mediocre reranking model.
+  ).
 - `reranker_params`: dictionary, similar to `embedding_params`. The options
   passed to the reranker class constructor. For `CrossEncoderReranker`, these
   are the options passed to the 

src/vectorcode/cli_utils.py

@@ -100,7 +100,7 @@ class Config:
     overlap_ratio: float = 0.2
     query_multiplier: int = -1
     query_exclude: list[Union[str, os.PathLike]] = field(default_factory=list)
-    reranker: Optional[str] = "CrossEncoderReranker"
+    reranker: Optional[str] = "NaiveReranker"
     reranker_params: dict[str, Any] = field(default_factory=lambda: {})
     check_item: Optional[str] = None
     use_absolute_path: bool = False

tests/test_cli_utils.py

@@ -113,7 +113,7 @@ async def test_config_import_from_missing_keys():
     assert config.chunk_size == 2500
     assert config.overlap_ratio == 0.2
     assert config.query_multiplier == -1
-    assert config.reranker == "CrossEncoderReranker"
+    assert config.reranker == "NaiveReranker"
     assert config.reranker_params == {}
     assert config.db_settings is None