refactor: Use same default_k value in MCP as for Cognee (#1977)

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Set default top_k value for MCP to be the same as the Cognee default
top_k value

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- [ ] Performance improvement
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<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **Improvements**
* Search operations now return 10 results by default instead of 5,
providing more comprehensive search results.

* **Style**
* Minor internal formatting cleanup in the client path with no
user-visible behavior changes.

<sub>✏️ Tip: You can customize this high-level summary in your review
settings.</sub>
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

cognee-mcp/src/cognee_client.py

@@ -192,9 +192,7 @@ class CogneeClient:
 
             with redirect_stdout(sys.stderr):
                 results = await self.cognee.search(
-                    query_type=SearchType[query_type.upper()],
-                    query_text=query_text,
-                    top_k=top_k
+                    query_type=SearchType[query_type.upper()], query_text=query_text, top_k=top_k
                 )
                 return results
 

cognee-mcp/src/server.py

@@ -316,7 +316,7 @@ async def save_interaction(data: str) -> list:
 
 
 @mcp.tool()
-async def search(search_query: str, search_type: str, top_k: int = 5) -> list:
+async def search(search_query: str, search_type: str, top_k: int = 10) -> list:
     """
     Search and query the knowledge graph for insights, information, and connections.
 
@@ -390,7 +390,7 @@ async def search(search_query: str, search_type: str, top_k: int = 5) -> list:
         The search_type is case-insensitive and will be converted to uppercase.
 
     top_k : int, optional
-        Maximum number of results to return (default: 5).
+        Maximum number of results to return (default: 10).
         Controls the amount of context retrieved from the knowledge graph.
         - Lower values (3-5): Faster, more focused results
         - Higher values (10-20): More comprehensive, but slower and more context-heavy