fix(mcp): extract and elevate struct docstrings into root tool schema descriptions to restore semantic LLM visibility

server/src/tools.rs

@@ -55,7 +55,7 @@ pub struct DeleteRelationsTool {
     pub relations: Vec<crate::models::Relation>,
 }
 
-/// Read the entire knowledge graph.
+/// Read the entire knowledge graph. WARNING: For large graphs, use search_nodes instead to avoid context limits.
 #[derive(Debug, Deserialize, Serialize, JsonSchema)]
 pub struct ReadGraphTool {
     /// Optional namespace to restrict the read to.