[BUG] Claude Code 2.1.263 crashes with Bun segmentation fault on Windows 11 — reproducible on trivial prompts

### Preflight Checklist

- [x] I have searched [existing issues](https://github.com/anthropics/claude-code/issues?q=is%3Aissue%20state%3Aopen%20label%3Abug) and this hasn't been reported yet
- [x] This is a single bug report (please file separate reports for different bugs)
- [x] I am using the latest version of Claude Code

### What's Wrong?

Claude Code repeatedly crashes with a Bun runtime segmentation fault when running inside the Antigravity IDE (VS Code-based) on Windows 11. The crash is not tied to any specific action — it has occurred on session startup and on the simplest possible prompt ("hi"), with no complex tool calls or file operations involved.

### What Should Happen?

Claude Code should respond to prompts and run normally without the underlying Bun runtime crashing.

### Error Messages/Logs

```shell
panic(main thread): Segmentation fault at address 0x0
oh no: Bun has crashed. This indicates a bug in Bun, not your code.
https://bun.report/1.4.1/w_183c373bmgggkQugogCizu1fuimgeA2AE

panic(main thread): Segmentation fault at address 0xE8
oh no: Bun has crashed. This indicates a bug in Bun, not your code.
https://bun.report/1.4.1/w_183c373bmgggkQugogC8lmgeA2AwO

panic(main thread): Segmentation fault at address 0xFFFFFFFFFFFFFFFF
oh no: Bun has crashed. This indicates a bug in Bun, not your code.
https://bun.report/1.4.1/w_183c373bmgggkQugogCg3v6dw1zn+DA2DD

panic(main thread): Segmentation fault at address 0x2
oh no: Bun has crashed. This indicates a bug in Bun, not your code.
https://bun.report/1.4.1/w_183c373bmgggkQugogCizu1fuimgeA2AE

panic(main thread): Segmentation fault at address 0x0
oh no: Bun has crashed. This indicates a bug in Bun, not your code.
https://bun.report/1.4.1/w_183c373bmgggkQugogCizu1fuimgeA2AA
```

### Steps to Reproduce

1. Open Antigravity IDE (VS Code-based) on Windows 11 with Claude Code 2.1.263 installed.
2. Open a standard git project (branch master).
3. Send any prompt in the Claude Code chat panel, including trivial ones like "hi".
4. Claude Code process exits with code 3; Bun panics with a segmentation fault.

Note: Crash occurs inconsistently at different points — sometimes on session startup before any prompt is sent, sometimes after a simple "hi" prompt. Memory addresses in the crash vary each time (0x0, 0xE8, 0xFFFFFFFFFFFFFFFF, 0x2), suggesting memory corruption rather than one deterministic trigger.

### Claude Model

None

### Is this a regression?

Yes, this worked in a previous version

### Last Working Version

2.1.111

### Claude Code Version

2.1.263

### Platform

Other

### Operating System

Windows

### Terminal/Shell

VS Code integrated terminal

### Additional Information

Running inside Antigravity IDE (Google's VS Code-based fork), not standard VS Code.

Already ruled out:
- Not caused by git extensions.worktreeConfig setting — removed it, crash persisted.
- Not caused by a specific plugin — disabled claude-mem@thedotmack, crash still occurred on a plain "hi" prompt with no plugin hooks logged before the crash.
- Even Antigravity's built-in feedback/crash-reporter dialog failed to submit, because the same Bun crash interrupted the reporting process itself mid-send.

Note: A closely related issue (#50640, "Claude Code v2.1.112+ crashes with Segmentation Fault (0xc0000005) on Windows 11") was reported in April 2026 for the same v2.1.112+ native-binary regression and closed as "not planned." This report demonstrates the same underlying crash pattern persists 5 months later on v2.1.263, suggesting it was not actually resolved.

Start by reproducing the crash from the Claude Code chat panel using the listed Windows 11 and Antigravity IDE steps, then inspect the supplied Bun crash-report URLs and compare versions 2.1.111 and 2.1.263. Done means Claude Code remains running and responds to trivial prompts without a Bun segmentation fault.

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