Bash tool silently promotes long-running commands to background without warning

Summary

Commands expected to run synchronously (e.g. npx jest --watchAll=false) are automatically promoted to background tasks, returning a background task ID instead of output. No warning is given before the promotion occurs.

Environment

• Claude Code CLI: 2.1.160
• OS: Windows 11

Steps to reproduce

1. Run a Jest or Maven command via Bash tool without run_in_background: true
2. Observe: command is silently promoted to background, returns task ID instead of output

Expected

Synchronous calls run synchronously. If a command is too long, warn before backgrounding it.

Impact

Forces polling loops or guesswork about when results will be available.