[Bug] Auto-update reports success with non-functional stub binary after postinstall link failure

Bug Description
Auto-update reports success while leaving a non-functional stub at bin/claude.exe

Environment

• Claude Code 2.1.222 → 2.1.228 (auto-update, path: npm-global)
• macOS Darwin 25.5.0, arm64
• node v22.23.1, npm 12.0.2
• Global root: ~/.local/lib/node_modules
• npm config get ignore-scripts → false; no omit in ~/.npmrc

What happened

Auto-update ran unattended and recorded success:

// ~/.claude/.last-update-result.json
{"timestamp":"2026-08-12T01:39:53.609Z","path":"npm-global","outcome":"success",
"status":"success","version_from":"2.1.222","version_to":"2.1.228","error_code":null}

The next claude invocation failed with:

Error: claude native binary not installed.
Either postinstall did not run (--ignore-scripts, some pnpm configs)
or the platform-native optional dependency was not downloaded (--omit=optional).

Both causes named in that message were false on this machine. ignore-scripts was false, and the platform dependency was downloaded correctly:

node_modules/@anthropic-ai/claude-code-darwin-arm64/claude 289298144 bytes ✅ Mach-O arm64
bin/claude.exe 500 bytes ❌ ASCII text

bin/claude.exe was a shell script that only prints the error above. ~/.local/bin/claude symlinks to it, so the CLI was unusable. The real binary sat one directory away, fully downloaded, correct version.

Root cause: postinstall's final link step (native package → bin/) did not run or silently failed, and the stub was left in place. The updater recorded outcome: success, error_code: null regardless.

Fix that worked

node ~/.local/lib/node_modules/@anthropic-ai/claude-code/install.cjs

bin/claude.exe became a hardlink to the real binary (link count 2, Mach-O arm64) and claude --version → 2.1.228 (Claude Code).

Two separate issues

1. Postinstall leaves a stub instead of linking a binary that is already present locally.
2. The updater cannot detect this. It reports success without verifying the resulting bin/ entry is executable — so the failure surfaces later, with a diagnostic pointing at two conditions that do not apply. A post-update check (file size, file type, or --version) would have caught it at 10:39 instead of at next use.

Environment Info

• Platform: darwin
• Terminal: Orca
• Version: 2.1.227
• Feedback ID: dcfb9221-aa47-46eb-ad17-69abd91db32d

Errors

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