毎度のことながら

Add your own ruleで以下を設定する。
{
"description": "ctrl + B in Codex",
"manipulators": [
{
"conditions": [
{
"bundle_identifiers": [
"^com\\.openai\\.codex$"
],
"type": "frontmost_application_if"
}
],
"from": {
"key_code": "b",
"modifiers": { "mandatory": ["control"] }
},
"to": [{ "key_code": "left_arrow" }],
"type": "basic"
}
]
}