When an agent uses subagents to implement code the files changes / lines written aren't counted correctly in the end

What version of the IDE extension are you using?

26.814.41407

What subscription do you have?

ChatGPT Pro 20x

Which IDE are you using?

VS Code

What platform is your computer?

Darwin 25.5.0 arm64 arm

What issue are you seeing?

When an agent uses subagents to implement code the files changes / lines written aren't counted correctly in the end

What steps can reproduce the bug?

Think of some random project / feature and get 5.6 Sol Ultra to build it and delegate work to subagents. When it finishes you will see that the lines reported in the end are only the ones the central agent wrote, not the subagents, thereby creating a misleading picture of the size of the implementation.

What is the expected behavior?

The expected behavior is to see all the lines changed by the agent AND the subagents combined, not just the central agent. It should equal the diff with what it had before the prompt was sent.

Additional information

No response

Reproduce the issue in the VS Code extension by asking an agent to delegate implementation to subagents, then compare the reported file and line counts with the final diff against the pre-prompt state. Trace the completion summary or usage-reporting entry point that produces those counts; done means the central agent and all subagent changes are included.