change_type: enhancement
component: gen-ai
note: |
  Add tool definitions and execution details for Single and Multi-Agent systems
  - Add 'gen_ai.tool.definitions' attribute to 'invoke_agent' span
  - Add 'gen_ai.tool.definitions' attribute to 'attributes.gen_ai.inference.client' attribute group.
  - Add 'gen_ai.tool.call.arguments' and 'gen_ai.tool.call.result' attributes to 'execute_tool' span.

issues: [2444, 591]