Add back intro detail to filters.md

Author: halter73

docs/concepts/filters.md

@@ -9,8 +9,8 @@ uid: filters
 
 The MCP Server provides two levels of filters for intercepting and modifying request processing:
 
-1. **Message Filters** - Low-level filters (`AddIncomingFilter`, `AddOutgoingFilter`) configured via `WithMessageFilters(...)`.
-2. **Request-Specific Filters** - Handler-level filters (e.g., `AddListToolsFilter`, `AddCallToolFilter`) configured via `WithRequestFilters(...)`.
+1. **Message Filters** - Low-level filters (`AddIncomingFilter`, `AddOutgoingFilter`) configured via `WithMessageFilters(...)` that intercept all JSON-RPC messages before routing.
+2. **Request-Specific Filters** - Handler-level filters (e.g., `AddListToolsFilter`, `AddCallToolFilter`) configured via `WithRequestFilters(...)` that target specific MCP operations.
 
 The filters are stored in `McpServerOptions.Filters` and applied during server configuration.