Claude Code terminal exits immediately on Synology NAS (kernel 4.4.x)

Description

Claude Code interactive terminal mode exits immediately after displaying the UI on Synology NAS devices. No error message is shown, exit code is 0.

Environment

• Device: Synology DS420+ (geminilake architecture)
• DSM Version: 7.x
• Kernel: 4.4.302+ (x86_64)
• Claude Code Version: 2.0.50

Behavior

• claude - Shows UI briefly, exits immediately with code 0
• claude --version - Works
• claude --help - Works
• claude -p "prompt" - Works (non-interactive mode)
• VSCode extension - Works perfectly

Testing Performed

1. Synology DS420+ (kernel 4.4.302): Interactive mode fails
2. Second Synology NAS (kernel 4.4.x): Interactive mode fails
3. Ubuntu 25.04 (kernel 6.14.0): Interactive mode works

Probable Cause

The Bun runtime requires Linux kernel 5.1+ for io_uring support. Synology DSM 7.x uses kernel 4.4.x on most NAS models (geminilake, apollolake, broadwell, etc.), which predates io_uring.

While Bun documentation mentions fallbacks for older kernels, the interactive TUI appears to require io_uring for terminal input handling.

Additional Issue

Synology mounts /tmp with noexec, which also causes issues. Workaround: export TMPDIR="$HOME/.tmp" in shell config.

Feature Request

Consider one of:

1. Graceful error message when kernel is incompatible instead of silent exit
2. Fallback mechanism for older kernels (if feasible)
3. Node.js-based alternative for systems without io_uring support

Workarounds

Users on Synology can use:

• VSCode extension (works perfectly)
• Non-interactive mode: claude -p "your question"
• SSH to a machine with kernel 5.1+