[BUG] Claude CLI returns empty output with large stdin input in headless mode

[geomna]

Preflight Checklist

• I have searched existing issues and this hasn't been reported yet
• This is a single bug report (please file separate reports for different bugs)
• I am using the latest version of Claude Code

What's Wrong?

Claude CLI in headless mode (-p flag) returns empty output when processing large stdin input (~7000+ characters), while smaller inputs (~2500 characters) work correctly.

What Should Happen?

Claude CLI should process large text input and return analysis results.

Error Messages/Logs

- Command exits with return code 0 (success)
- Empty stdout output (0 characters)
- No stderr errors
- `--verbose` flag provides no additional information

Steps to Reproduce

1. Create a test file with ~7000 characters of content
2. Run: cat testfile.txt | claude -p --verbose --append-system-prompt "Analyze this content" --output-format text
3. Observe empty output despite successful exit code

Claude Model

Not sure / Multiple models

Is this a regression?

I don't know

Last Working Version

No response

Claude Code Version

1.0.108

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Non-interactive/CI environment

Additional Information

Test Results

• Input size ~2350 characters: Returns expected output (1904 characters)
• Input size ~6986 characters: Returns empty output (0 characters)
• Both cases: exit code 0, no stderr errors

Impact
This prevents using Claude CLI for processing large documents, code reviews, or batch text analysis in automated workflows.

[github-actions]

Found 3 possible duplicate issues:

1. [BUG] CLI streaming files silently hangs and fails when token limit is exceeded #4869
2. [BUG] Input buffer becomes unusable with large prompts #7226
3. [BUG] Raw mode is not supported on the current process.stdin cat <filename> | claude with several options #6609

This issue will be automatically closed as a duplicate in 3 days.

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🤖 Generated with Claude Code

[baojiliu]

Same issues here 😅

[geomna]

Same issues here 😅

I found workaround by storing data in tmp file and telling in short prompt to read that file. Probably its better way to put large bunch of information.

[marwin1991]

Same problem here, I tried @geomna workaround but it does not help

What i have discovered is that:

claude --verbose -d --print "/doctor" 

returns empty, everything starts from / returns empty.

My prompt is Perform code review and give output to the console using instruction from .claude/commands/code-review.md

But when i run it local, everything works, but on docker image, there is empty response

[marwin1991]

I am wondering, maybe it is a problem with proxy blocking streaming?

[github-actions]

This issue has been inactive for 30 days. If the issue is still occurring, please comment to let us know. Otherwise, this issue will be automatically closed in 30 days for housekeeping purposes.

[github-actions]

This issue has been automatically closed due to 60 days of inactivity. If you're still experiencing this issue, please open a new issue with updated information.