docs: update README.md

Author: seratch

README.md

@@ -10,7 +10,7 @@ The OpenAI Agents SDK is a lightweight yet powerful framework for building multi
 ### Core concepts:
 
 1. [**Agents**](https://openai.github.io/openai-agents-python/agents): LLMs configured with instructions, tools, guardrails, and handoffs
-1. [**Agents as tools / Handoffs**](https://openai.github.io/openai-agents-python/handoffs/): Delegating to other agents for specific tasks
+1. **[Agents as tools](https://openai.github.io/openai-agents-python/tools/#agents-as-tools) / [Handoffs](https://openai.github.io/openai-agents-python/handoffs/)**: Delegating to other agents for specific tasks
 1. [**Tools**](https://openai.github.io/openai-agents-python/tools/): Various Tools let agents take actions (functions, MCP, hosted tools)
 1. [**Guardrails**](https://openai.github.io/openai-agents-python/guardrails/): Configurable safety checks for input and output validation
 1. [**Human in the loop**](https://openai.github.io/openai-agents-python/human_in_the_loop/): Built-in mechanisms for involving humans across agent runs