Claude Code Write Tool Produces PowerShell UTF-8 Without BOM Caarsing UnexpectedToken Errors on Windows

What this error means

UnexpectedToken / ParserError in PowerShell when running .ps1 files created by Claude Code Write tool is a Claude Code failure pattern reported for developers trying to fix claude code write tool powershell utf-8 bom issue causing unexpectedtoken errors on windows. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.

Why this happens

Open issue on official anthropics/claude-code repo. Clear repro steps documented. Write tool creates .ps1 files without BOM, PowerShell 5.1 throws UnexpectedToken at Unicode characters. Affects Windows developers with non-ASCII content in scripts.

Common causes

• Claude Code’s Write tool creates .ps1 files as UTF-8 without BOM. PowerShell 5.1 on Windows interprets these as ANSI, causing ParserError at non-ASCII characters (emojis, em dash, umlauts). Affects Windows developers using Claude Code for automation scripts.
• Open issue on official anthropics/claude-code repo. Clear repro steps documented. Write tool creates .ps1 files without BOM, PowerShell 5.1 throws UnexpectedToken at Unicode characters. Affects Windows developers with non-ASCII content in scripts.

Quick fixes

1. Confirm the exact error signature matches UnexpectedToken / ParserError in PowerShell when running .ps1 files created by Claude Code Write tool.
2. Check the Claude Code account, local tool state, and provider configuration involved in the failing workflow.
3. Compare the failing environment with a known working setup, then change one configuration value at a time.

Platform/tool-specific checks

• Verify the command, editor, extension, or API client that produced the error.
• Compare local settings with CI, deployment, or editor-level settings when the error appears in only one environment.
• Avoid deleting credentials, local model data, or project settings until the failing scope is clear.

Step-by-step troubleshooting

1. Capture the exact error message and the command, editor action, or request that triggered it.
2. Check whether the failure is account/auth, quota/rate, model/provider, local runtime, or deployment configuration.
3. Review the source evidence below and compare it with your environment.
4. Apply one change at a time and rerun the smallest failing action.
5. Keep the working fix documented for the team or deployment environment.

How to prevent it

• Keep provider/tool configuration documented.
• Record non-secret diagnostics such as tool version, provider name, model name, and command path.
• Add a lightweight check before CI or production workflows depend on the tool.

Sources checked

• https://github.com/anthropics/claude-code/issues/58545

Evidence note: Open issue on official anthropics/claude-code repo. Clear repro steps documented. Write tool creates .ps1 files without BOM, PowerShell 5.1 throws UnexpectedToken at Unicode characters. Affects Windows developers with non-ASCII content in scripts.

Related errors

• Claude Code PowerShell encoding issue
• Claude Code Windows path error

FAQ

What should I check first?

Start with the exact UnexpectedToken / ParserError in PowerShell when running .ps1 files created by Claude Code Write tool text and the smallest action that reproduces it.

Can I ignore this error?

No. Treat it as a failed Claude Code workflow until the root cause is understood.

Is this guaranteed to have one fix?

No. The imported evidence supports the troubleshooting path above, but tool behavior can vary by account, plan, version, provider, and local configuration.

How do I know the fix worked?

Rerun the same command, editor action, or request. The fix is working when that action completes without UnexpectedToken / ParserError in PowerShell when running .ps1 files created by Claude Code Write tool.