Bugfix/Tool Agent output message

[HenryHengZJ]

When using Anthropic, the output has the following format:

[
  {
    index: 0,
    type: 'text',
    text: 'Hello! How can I assist you today?'
  }
]

This causes error when we try to regex.

Fix: check if its array, if yes take the text from the first item