[BUG] Cannot Create Multi-line Prompts in CLI

Preflight Checklist

• [x] I have searched existing issues 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?

# Bug Report: Cannot Create Multi-line Prompts in CLI

## Description
The Claude Code CLI does not support creating multi-line prompts interactively. Users cannot press Enter/Return to create a new line within their prompt, which significantly limits the ability to provide complex,
formatted instructions.

## Environment

• Platform: macOS (Darwin 24.6.0)
• Claude Code Version: [Please add version - run claude --version]

## Current Behavior
When typing a prompt in the Claude Code CLI, pressing Enter/Return immediately submits the prompt instead of creating a new line. This makes it impossible to:

• Format complex instructions across multiple lines
• Paste multi-line code or text
• Create structured prompts with proper formatting
• Provide context that requires paragraph breaks

## Expected Behavior
Users should be able to:

1. Press Enter/Return to create new lines within a prompt
2. Use a specific key combination (e.g., Shift+Enter or Ctrl+Enter) to submit the prompt
3. Or have a clear delimiter/command to indicate prompt completion

## Workarounds Currently Required
Users must resort to less intuitive methods:

• Using \n escape sequences in quoted strings
• Piping input from files: cat prompt.txt | claude
• Using heredoc syntax (if supported)
• Using echo with escape sequences: echo -e "line1\nline2" | claude

## Impact
This limitation reduces the usability of the CLI for:

• Complex debugging scenarios
• Code review requests
• Multi-step instructions
• Any use case requiring formatted input

## Suggested Solution
Implement one of the following:

1. Multi-line input mode: Enter key creates new lines, special key combo (Shift+Enter, Ctrl+D, etc.) submits
2. Visual indicator: Show when in multi-line mode with a continuation prompt (e.g., > for first line, ... for continuation)
3. Command flag: Add a flag like --multiline to enable multi-line input mode
4. Editor integration: Provide a --editor flag that opens the default text editor for composing prompts

## Additional Context
This is a common pattern in other CLI tools:

• Python REPL uses continuation prompts (>>> and ...)
• PostgreSQL CLI (psql) continues until semicolon
• Many modern CLIs use Ctrl+D or specific delimiters for multi-line input

What Should Happen?

shift+enter or enter should create a newline

Error Messages/Logs

Steps to Reproduce

press shift enter or ctrl enter or anything else. there is no way to add newlines in a prompt, so claude continues to do the wrong thing as it tries to follow partial directions.

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.0.5 (Claude Code)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

IntelliJ IDEA terminal

Additional Information

_No response_