Consistent Bun crash: 'directory mismatch for tsconfig.json' — Claude Code process exits with code 1

[pyalavarthi-fliptrx]

Description

claude-code-action consistently crashes on startup with Internal error: directory mismatch for directory tsconfig.json before Claude makes any API call. The Bun runtime exits with code 1 immediately after SDK initialization.

Error

SDK execution error: 53 | new Anthropic({ apiKey, dangerouslyAllowBrowser: true });
error: Claude Code process exited with code 1
Internal error: directory mismatch for directory "/home/runner/work/_actions/anthropics/claude-code-action/657fb7c9c986158a19624b357bcbc8c6deb83598/tsconfig.json", fd 4. You don't need to do anything, but this indicates a bug.

Environment

• Runner: ubuntu-24.04 (image 20260406.80.1) and ubuntu-22.04 (image 20260406.82.1) — both crash
• Bun: 1.3.6+d530ed993 (installed by the action via oven-sh/setup-bun)
• Claude Code: 2.1.98 (native build, installed by the action)
• Action versions tested: @v1 (v1.0.92), @v1.0.90, @v1.0.89, pinned SHA 657fb7c9c986158a19624b357bcbc8c6deb83598
• All crash identically.

What Works vs What Doesn't

Time	Runner Image	Action Version	Result
April 9, 21:15 UTC	ubuntu-24.04, 20260406.80.1	@v1 (resolved to 657fb7c)	Success — full run completed
April 9, 22:22 UTC	ubuntu-24.04, 20260406.80.1	@v1 (resolved to 657fb7c)	Success — full run completed
April 9, 23:03 UTC	ubuntu-24.04, 20260406.80.1	@v1	Failure — tsconfig crash
April 10, 03:07-03:28 UTC	ubuntu-24.04/22.04	@v1.0.90, @v1.0.89, pinned SHA	All fail — tsconfig crash
April 10, 07:01 UTC	ubuntu-24.04, 20260406.80.1	pinned SHA 657fb7c	Failure — tsconfig crash

The same action SHA that succeeded at 22:22 UTC crashes at 23:03 UTC on the same runner image version. No workflow changes between the runs.

Reproduction

Minimal workflow:

name: Test
on: workflow_dispatch
jobs:
  test:
    runs-on: ubuntu-24.04
    steps:
      - uses: actions/checkout@v4
      - uses: anthropics/claude-code-action@v1
        with:
          anthropic_api_key: ${{ secrets.ANTHROPIC_API_KEY }}
          prompt: "Say hello"
          claude_args: "--model claude-sonnet-4-6 --max-turns 1"
          github_token: ${{ secrets.GITHUB_TOKEN }}

Failed Run Links

• https://github.com/FliptRx/fliptrx-requirements/actions/runs/24224823332
• https://github.com/FliptRx/fliptrx-requirements/actions/runs/24224713945
• https://github.com/FliptRx/fliptrx-requirements/actions/runs/24224649730
• https://github.com/FliptRx/fliptrx-requirements/actions/runs/24224440732

Analysis

The crash occurs in the Bun runtime's file descriptor handling (fd 4) when resolving tsconfig.json. It's not version-specific (tested 3 versions + pinned SHA) and not runner-OS-specific (tested ubuntu-22.04 and ubuntu-24.04). The error message itself says "You don't need to do anything, but this indicates a bug" — it appears to be a known Bun issue that became consistently reproducible after ~23:00 UTC on April 9, 2026.

The same error appears as a non-fatal warning in some successful runs (e.g., in the post-step cleanup), but in the failing runs it crashes the main Claude Code process before any API call is made.

[pyalavarthi-fliptrx]

Update: Further testing confirms this is a Claude Code 2.1.98 bug, not a Bun version or action version issue.

We tested:

• Pre-installing Bun 1.2.12 (verified via bun --revision = 1.2.12+32a47ae45) — still crashes
• Clearing ~/.bun/install/cache and ~/.claude before the action — still crashes
• ubuntu-22.04 and ubuntu-24.04 — both crash

The crash happens at new Anthropic({ apiKey, dangerouslyAllowBrowser: true }) inside Claude Code's startup, before any API call is made. Claude Code version: 2.1.98 (native build).

The directory mismatch for tsconfig.json error appears to be a symptom of Claude Code's internal Bun-based runtime, not the system Bun installation. The action's embedded Bun binary or Claude Code's native build may have a corrupted file descriptor table.

The same Claude Code version (2.1.98) worked on April 9 22:22 UTC and crashes on April 9 23:03 UTC onwards. No code changes between the runs.

[FredericOdermatt]

I've got the same issue. Can confirm as mentioned above, not fixed when pinning claude-code-action to either v1.0.91 or v1.0.90

I had the last successful run at around 11:30 UTC today