2.1.206 linux-x64 ships a Bun baseline build that segfaults on startup (glibc 2.41)

Summary

The linux-x64 native binary shipped in @anthropic-ai/claude-code@2.1.206 is a Bun 1.4.0 baseline build, and it segfaults (SIGSEGV, exit 139) on startup on Debian 13 (glibc 2.41). Even claude --version crashes 100% of the time.

2.1.205 on the exact same machine is fine (normal build, exit 0, no crash). This is a regression introduced in 2.1.206.

Environment

• OS: Debian GNU/Linux 13 (trixie)
• Kernel: 6.17.2
• glibc: 2.41
• CPU: Intel Core i5-9500 (supports sse4_2 avx avx2)
• Node: v20.20.2, npm: 11.12.1
• Install: npm i -g, prefix /usr
• Package: @anthropic-ai/claude-code@2.1.206, native dep @anthropic-ai/claude-code-linux-x64@2.1.206

Reproduction

$ claude --version
============================================================
Bun v1.4.0 (63bb0ca0d) Linux x64 (baseline)
Linux Kernel v6.17.2 | glibc v2.41
CPU: sse42 popcnt avx avx2
Args: "claude" "--version"
Features: jsc standalone_executable claude_code
Builtins: "bun:main"

panic(main thread): Segmentation fault at address 0x...
oh no: Bun has crashed. This indicates a bug in Bun, not your code.

Exit code 139 (SIGSEGV), reproducible 5/5 runs.

Diagnosis

The native binary at .../claude-code-linux-x64/claude reports itself as a Bun baseline build:

Bun v1.4.0 (63bb0ca0d) Linux x64 (baseline)

The CPU has avx2, so a baseline build should not have been shipped for this target, and the baseline build itself faults during runtime init on glibc 2.41.

Binary size also jumped: linux-x64 tgz went from ~79 MB (2.1.205) to a ~258 MB uncompressed binary (2.1.206), consistent with a different Bun build variant being packaged.

Version comparison on the same host

Same machine, same npm, --version run 5 times each:

| Version | Result |
|---------|--------|
| 2.1.205 | 5/5 exit 0, prints 2.1.205 (Claude Code), no crash |
| 2.1.206 | 5/5 exit 139 (SIGSEGV), Bun baseline crash banner |

Workaround

Pin to the last good release and disable auto-update (otherwise the updater pulls 2.1.206 again):

npm i -g @anthropic-ai/claude-code@2.1.205
# settings.json: "autoUpdates": false   (and/or DISABLE_AUTOUPDATER=1)

Expected

linux-x64 should ship the non-baseline Bun build for AVX2-capable CPUs (as 2.1.205 did), and/or the baseline build should not segfault on glibc 2.41.