Enhancement: tab-completion for magic commands

[thehighnotes]

Description

OI already imports readline and uses it for up-arrow history recall, but there is no tab-completion for magic commands. Users must remember the exact spelling of %save_message, %load_message, %verbose, etc. There are 12+ magic commands with no discoverability.

Suggested implementation

Add a readline completer that activates when input starts with %:

def _oi_completer(text, state):
    MAGIC_COMMANDS = [
        "%help", "%reset", "%undo", "%verbose", "%auto_run",
        "%save_message", "%load_message", "%tokens",
        "%info", "%jupyter", "%markdown", "%%",
    ]
    if text.startswith("%"):
        matches = [c for c in MAGIC_COMMANDS if c.startswith(text)]
    else:
        matches = []
    return matches[state] if state < len(matches) else None

Register in the existing readline try block in terminal_interface.py:

readline.set_completer(_oi_completer)
readline.set_completer_delims(" \t\n")
readline.parse_and_bind("tab: complete")

Behavior:

• % + Tab → shows all magic commands
• %re + Tab → completes to %reset
• Non-% input → no completion (preserves default behavior)
• Up-arrow history unaffected

Minimal change (~15 lines), no new dependencies.

Environment

• open-interpreter 0.4.3
• Python 3.10, Linux (readline available)