Agent tool internal output (agentId, file paths, instructions) exposed in mobile UI

Bug Description

When using Claude Code via mobile (Google Remote Control / VSCode mobile), the Agent tool's internal output is displayed directly to the user in the UI. This includes information explicitly marked as "internal ID - do not mention to user".

What is shown

• agentId (internal tracking ID)
• output_file path (local filesystem path with full absolute path)
• Internal instructions ("Do not duplicate this agent's work...", "Do not mention to user")
• System metadata that should be hidden from end users

Expected behavior

The Agent tool's raw launch confirmation should be invisible to the user. Only the agent's final result/summary should be displayed.

Steps to reproduce

1. Open Claude Code on mobile via Google Remote Control
2. Trigger any task that launches a background Agent (subagent)
3. Observe the raw agent launch output displayed in a modal/popup titled "Agent" > "Saida"

Screenshot

The popup shows the full raw output including:

Async agent launched successfully.
agentId: a370e11ea8f2d7745 (internal ID - do not mention to user. Use to resume later if needed.)
The agent is working in the background. You will be notified automatically when it completes.
Do not duplicate this agent's work - avoid working with the same files or topics it is using.
output_file: C:\Users\vitoo\AppData\Local\Temp\claude\...\tasks\a370e11ea8f2d7745.output
If asked, you can check progress before completion by using Read or Bash tail on the output file.

Environment

• Claude Code VSCode Extension (mobile access via Google Remote Control)
• Windows 10 Pro 10.0.19045 host
• Claude Opus 4.6