fix typo

docs/core_docs/docs/tutorials/agents.mdx

@@ -100,7 +100,7 @@ console.log(retrieverResult[0]);
 */
 ```
 
-Now that we have populated our index that we will bo doing retrieval over, we can easily turn it into a tool (the format needed for an agent to properly use it):
+Now that we have populated our index that we will be doing retrieval over, we can easily turn it into a tool (the format needed for an agent to properly use it):
 
 ```typescript
 import { createRetrieverTool } from "langchain/tools/retriever";