{
  "context": "This evaluation assesses how well the engineer uses Node.js child process APIs to execute external checker programs, handle their stdin/stdout communication, and implement proper timeout and error handling. The focus is on correctly spawning external processes, managing their I/O streams, and implementing a validation pipeline that follows the external checker protocol.",
  "type": "weighted_checklist",
  "checklist": [
    {
      "name": "External Process Execution",
      "description": "Uses Node.js child_process module (spawn, exec, or execFile) to execute external checker programs. Should properly handle the checker program path and spawn the process.",
      "max_score": 20
    },
    {
      "name": "Stdin/Stdout Communication",
      "description": "Implements proper stdin/stdout communication with checker processes by writing tool invocation JSON to stdin and reading validation decision JSON from stdout. Should use proper stream handling (e.g., process.stdin.write, process.stdout.on('data')).",
      "max_score": 25
    },
    {
      "name": "Timeout Implementation",
      "description": "Implements configurable timeout for checker execution using setTimeout, AbortController, or child process timeout options. Should properly terminate timed-out processes and treat timeout as 'allow' (fail-open).",
      "max_score": 20
    },
    {
      "name": "Error Handling",
      "description": "Handles checker process errors (exit codes, stderr, spawn errors) appropriately by treating errors as 'allow' decisions per the fail-open requirement. Should handle both process-level errors and invalid JSON responses.",
      "max_score": 15
    },
    {
      "name": "Sequential Checker Execution",
      "description": "Implements sequential checker execution that stops early when a checker blocks. Should use async/await or Promise chains to run checkers in order and short-circuit on first 'block' decision.",
      "max_score": 15
    },
    {
      "name": "JSON Parsing",
      "description": "Properly parses JSON input from checker stdout and constructs JSON to send to checker stdin. Should use JSON.parse and JSON.stringify correctly and handle parsing errors gracefully.",
      "max_score": 5
    }
  ]
}