[FEATURE] allow passing initial user query via command line argument

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

I often want to start claude with a system prompt + initial user prompt (so it automatically starts processing).
this is kind of like headless mode, except that i want to start claude and see what it does and then stay in interactive mode after its finished so i can continue conversing with it.

Proposed Solution

claude --user-prompt '.....' and claude runs this user prompt on startup.

Alternative Solutions

_No response_

Priority

Critical - Blocking my work

Feature Category

CLI commands and flags

Use Case Example

_No response_

Additional Context

_No response_