opencode/opencode.json

{
  "$schema": "https://opencode.ai/config.json",
  "experimental": {
    "hook": {
      "file_edited": {
        ".json": [
          {
            "command": ["bun", "run", "prettier", "$FILE"]
          }
        ]
      },
      "session_completed": [
        {
          "command": ["touch", "./node_modules/foo"]
        }
      ]
    }
  }
}