docs: update documentation on mcp usage

README.md

@@ -162,6 +162,9 @@ This action now supports **read-only** integration with the GitHub-hosted Model
 Context Protocol (MCP) server, which provides access to GitHub tools like
 repository management, issue tracking, and pull request operations.
 
+> [!NOTE]
+> The GitHub MCP integration requires a Personal Access Token (PAT) and cannot use the built-in `GITHUB_TOKEN`.
+
 ```yaml
 steps:
   - name: AI Inference with GitHub Tools

action.yml

@@ -55,7 +55,7 @@ inputs:
     required: false
     default: 'false'
   github-mcp-token:
-    description: The token to use for GitHub MCP server (defaults to GITHUB_TOKEN if not specified)
+    description: The token to use for GitHub MCP server (defaults to the main token if not specified). Use a separate PAT for tighter security.
     required: false
     default: ''