[Bug] Random text insertion in agent harness under high concurrent load (20+ agents)

Bug Description
Issue: Random "hello" text insertions in agent harness when running 20+ Claude Code Terminal CLI agents simultaneously on Mac Details: • Occurs consistently when running more than 20 agents concurrently • Below 20 agents, everything works fine • Random "hello" strings appear inserted into the main agent harness • Ruled out tmux and external causes • Only happens under high agent load • Agents otherwise function correctly, but the crosstalk is concerning Environment: Claude Code Terminal CLI (not SDK or direct API calls), macOS Reproducibility: Consistently replicable at 20+ concurrent agents This appears to be a multi-agent isolation or resource contention issue that becomes apparent at scale.

Environment Info

• Platform: darwin
• Terminal: vscode
• Version: 2.1.183
• Feedback ID: 86d357f7-e17d-41e4-926a-2614fffc1e3c

Errors

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