Bug Description

When voice.record_key is set to an empty string ("") in ~/.hermes/config.yaml, the interactive REPL (hermes) crashes immediately after the welcome banner with:

Error: Invalid key:

The crash occurs during prompt_toolkit keybinding registration in cli.py:run(). _voice_key is derived from load_config().get("voice", {}).get("record_key", "ctrl+b"), but .get() only fires the default when the key is absent — not when it is present with value "". The empty string propagates to kb.add(""), which raises ValueError("Invalid key: ") from prompt_toolkit/key_binding/key_bindings.py:455.

This bubbles up through cli.run() → cli.main() → cmd_chat() where it's caught by except ValueError as e: print(f"Error: {e}"). The error message looks like an API key authentication failure but is actually a keyboard-binding registration error.

Steps to Reproduce

1. Set voice.record_key: "" in ~/.hermes/config.yaml
2. Run hermes (interactive REPL)
3. Observe: banner displays → "Welcome to Hermes Agent!" → tip → Error: Invalid key: → crash

Expected Behavior

An empty record_key should fall back to the default "ctrl+b" (or at minimum produce a clear error message indicating the config key is invalid, not an API key error).

Actual Behavior

REPL crashes with misleading "Invalid key" error that appears to be an API authentication failure. One-shot mode (hermes chat -q "test") works fine because it doesn't register prompt_toolkit keybindings. TUI also works because it has a separate code path.

Root Cause

In cli.py, three locations read voice.record_key via load_config().get("voice", {}).get("record_key", "ctrl+b"):

• Line ~8579: voice mode activation display
• Line ~8649: voice mode status display
• Line ~10564: REPL keybinding registration (@kb.add(_voice_key))

The .get("record_key", "ctrl+b") default only applies when the key is absent from the config dict. When record_key: "" is explicitly set (e.g., intentionally for hands-free VAD mode per docs), the empty string is used directly, causing the crash at line ~10564.

Proposed Fix

Add a guard after reading _raw_key:

_raw_key = load_config().get("voice", {}).get("record_key", "ctrl+b")
if not _raw_key:          # catches "" as well as None/missing
    _raw_key = "ctrl+b"
_voice_key = _raw_key.lower().replace("ctrl+", "c-").replace("alt+", "a-")

Apply at all three sites.

Related

• #11387: voice.record_key: alt+* crashes startup — same class of bug (invalid key format → prompt_toolkit ValueError) but different root cause.

Environment

• OS: macOS
• Hermes version: git-installed (HEAD: 026a5e47d)
• Python: 3.11