Shift+Enter is interpreted as Enter, making it impossible to properly format input question .

Environment

• Platform (select one):
• [x] Anthropic API
• [ ] AWS Bedrock
• [ ] Google Vertex AI
• [ ] Other: <!-- specify -->
• Claude CLI version: 1.0.17
• Operating System: Windows 11, Ubuntu WSL 2
• Terminal: bash

Bug Description

Shift+Enter does not work to create multi-line input in Claude Code CLI, making it
difficult to enter complex questions, code snippets, or detailed instructions that
require multiple lines.

Steps to Reproduce

1. Open Claude Code CLI
2. Start typing a message in the input prompt
3. Press Shift+Enter to attempt to add a new line
4. The question is submitted even though Enter was not pressed. Shift+Enter is interpreted as Enter.

Expected Behavior

Shift+Enter should allow users to create multi-line input, similar to other chat
interfaces and development tools, enabling entry of formatted questions, code blocks,
and detailed instructions.

Actual Behavior

Shift+Enter is interpreted as Enter, causing questions to be prematurely submitted and making it impossible to paste example text into the question.

Additional Context

This significantly impacts developer workflow when trying to ask questions about code,
provide multi-line examples, or give detailed instructions. The limitation makes users
consider using alternative tools, every single one of which allows multi-line input.