ask-tty

stdin support for Claude Code

The built-in Bash tool does not support stdin. Two tools solve this:

1. InteractiveBash (MCP tool) — when you know the input

Use when you already have the stdin content (e.g., piping "y" to a prompt, feeding a heredoc).

InteractiveBash(command: "apt install -y nginx", stdin: "y\n")
InteractiveBash(command: "cat > /tmp/config.json", stdin: '{"key":"value"}')

2. ask-tty (CLI + hook) — when you need to ask the user

Use when you need input from the user (passwords, confirmations you can't decide).

Flow

1. Run the command with ask-tty using run_in_background: true
2. Tell the user what input is needed and to type res:<their input>
3. When you see the user's res: message, immediately use TaskOutput to check the background task

sudo

echo $(~/bin/ask-tty "sudo password" --sensitive) | sudo -S <command>

Then tell the user: "Type res:yourpassword"

ssh password

sshpass -p "$(~/bin/ask-tty "SSH password for user@host" --sensitive)" ssh user@host <command>

y/N confirmation (when user must decide)

ANSWER=$(~/bin/ask-tty "Proceed? (y/N)")
echo "$ANSWER" | <command>

Then tell the user: "Type res:y or res:n"

When to use which

Scenario	Tool
You know the input (y/n, config, heredoc)	InteractiveBash
User must provide input (password, decision)	ask-tty
sudo with password	ask-tty (password stays hidden)
sudo with NOPASSWD	regular Bash tool

When the user types res: or tty:

The hook has delivered the input to the background ask-tty process. Immediately:

1. Do NOT repeat, display, or reference the content after res: / tty:
2. Reply only: "Received."
3. Use TaskOutput with the background task ID to check the result
4. Report the command output to the user

Important

• Always use run_in_background: true for Bash tool calls containing ask-tty
• Always use --sensitive for passwords
• Always use full path ~/bin/ask-tty
• Never repeat, echo, or reference the content after res: / tty:
• Never read ~/.cache/ask-tty/response directly
• If ask-tty fails (timeout, config missing), inform the user and do not retry