lang

/npc:lang — set preferred language

Read the argument:

• auto → remove the language key so the plugin auto-detects from system preferences on each event
• <code> where <code> is a 2-letter lowercase ISO 639-1 code (e.g. en, ru) → set language
• Anything else → print Language must be a 2-letter ISO code (e.g., en, ru). and stop

Validate <code> against ^[a-z]{2}$. If invalid, print: Language must be a 2-letter ISO code (e.g., en, ru). and stop.

Set language (lang <code>)

python3 -c "
import json, os
cfg_path = os.environ.get('NPC_CONFIG', os.path.expanduser('~/.claude/npc.json'))
try:
    with open(cfg_path) as f: c = json.load(f)
except Exception: c = {}
c['language'] = '<code>'
os.makedirs(os.path.dirname(cfg_path), exist_ok=True)
with open(cfg_path, 'w') as f: json.dump(c, f, indent=2)
print('done')
"

Confirm: Language set to <code>.

Note: the plugin does not validate the code against the active theme. If the theme does not support <code>, it falls back to the theme's defaultLanguage at runtime.

Reset language (lang auto)

python3 -c "
import json, os
cfg_path = os.environ.get('NPC_CONFIG', os.path.expanduser('~/.claude/npc.json'))
try:
    with open(cfg_path) as f: c = json.load(f)
except Exception: c = {}
c.pop('language', None)
os.makedirs(os.path.dirname(cfg_path), exist_ok=True)
with open(cfg_path, 'w') as f: json.dump(c, f, indent=2)
print('done')
"

Confirm: Language set to auto-detect.