#!/usr/bin/env python3 """Bounded, receipt-producing queue loop for an agent CLI. Queue rows are JSON objects with an ``id`` and ``objective``. The loop skips completed IDs, passes one item at a time to an agent command, runs an external verification command, and persists every attempt as JSONL state. The script edits nothing itself. Run it in a branch, worktree, or sandbox that matches the permissions described in each queue item. """ from __future__ import annotations import argparse import datetime as dt import json import os import shlex import subprocess import sys from pathlib import Path from typing import Any def load_jsonl(path: Path) -> list[dict[str, Any]]: rows: list[dict[str, Any]] = [] seen_ids: set[str] = set() for number, line in enumerate(path.read_text(encoding="utf-8").splitlines(), start=1): if not line.strip(): continue try: row = json.loads(line) except json.JSONDecodeError as error: raise ValueError(f"{path}:{number}: invalid JSON: {error}") from error if not isinstance(row, dict) or not isinstance(row.get("id"), str) or not row["id"].strip(): raise ValueError(f"{path}:{number}: each row needs a non-empty string 'id'") if not isinstance(row.get("objective"), str) or not row["objective"].strip(): raise ValueError(f"{path}:{number}: each row needs a non-empty string 'objective'") if row["id"] in seen_ids: raise ValueError(f"{path}:{number}: duplicate item id {row['id']!r}") seen_ids.add(row["id"]) rows.append(row) return rows def completed_ids(state_path: Path) -> set[str]: if not state_path.exists(): return set() completed: set[str] = set() for number, line in enumerate(state_path.read_text(encoding="utf-8").splitlines(), start=1): if not line.strip(): continue try: row = json.loads(line) except json.JSONDecodeError as error: raise ValueError(f"{state_path}:{number}: invalid JSON: {error}") from error if not isinstance(row, dict) or not isinstance(row.get("id"), str): raise ValueError(f"{state_path}:{number}: each receipt needs a string 'id'") if row.get("status") == "completed": completed.add(row["id"]) return completed def append_receipt(state_path: Path, receipt: dict[str, Any]) -> None: state_path.parent.mkdir(parents=True, exist_ok=True) with state_path.open("a", encoding="utf-8") as handle: handle.write(json.dumps(receipt, ensure_ascii=True, sort_keys=True) + "\n") def utc_now() -> str: return dt.datetime.now(dt.timezone.utc).isoformat(timespec="seconds") def command_argv(command: str, *, item_id: str) -> list[str]: return [argument.replace("{id}", item_id) for argument in shlex.split(command)] def main() -> int: parser = argparse.ArgumentParser(description=__doc__) parser.add_argument("--queue", type=Path, required=True, help="JSONL work queue") parser.add_argument("--state", type=Path, default=Path("QUEUE_PROGRESS.jsonl"), help="durable JSONL receipt log") parser.add_argument("--agent-command", help="agent CLI; the item prompt is appended as one argument") parser.add_argument("--verify-command", help="deterministic command; {id} expands to the current item ID") parser.add_argument("--max-items", type=int, default=5, help="maximum unprocessed items per run") parser.add_argument("--max-retries", type=int, default=2, help="agent attempts per item") parser.add_argument("--command-timeout", type=int, default=900, help="seconds allowed for each agent or verifier command") parser.add_argument("--dry-run", action="store_true", help="validate and display pending work without invoking commands") args = parser.parse_args() if args.max_items < 1 or args.max_retries < 1 or args.command_timeout < 1: parser.error("--max-items, --max-retries, and --command-timeout must be positive") if not args.dry_run and (not args.agent_command or not args.verify_command): parser.error("--agent-command and --verify-command are required unless --dry-run is used") try: queue = load_jsonl(args.queue) done = completed_ids(args.state) except (OSError, ValueError) as error: print(error, file=sys.stderr) return 3 pending = [item for item in queue if item["id"] not in done][: args.max_items] if args.dry_run: print(json.dumps({"queue_items": len(queue), "completed": len(done), "pending_this_run": pending}, indent=2)) return 0 if not pending: print("[queue] no pending work") return 0 agent_argv = command_argv(args.agent_command, item_id="") for item in pending: item_id = item["id"] print(f"[queue] processing {item_id}", file=sys.stderr) for attempt in range(1, args.max_retries + 1): prompt = "\n".join( [ "You are one bounded worker inside a durable work-queue loop.", "", "Work item:", json.dumps(item, indent=2, ensure_ascii=True), "", f"Attempt: {attempt} of {args.max_retries}", f"Command timeout: {args.command_timeout} seconds", f"State log: {args.state}", "", "Rules:", "- Read repository instructions and prior receipts before acting.", "- Stay inside the permissions and scope named by the item.", "- Make the smallest change that satisfies the objective.", "- Do not decide that the item is complete; an external command verifies it.", "- Leave enough evidence for a human to review the attempt.", ] ) try: agent_result = subprocess.run([*agent_argv, prompt], check=False, timeout=args.command_timeout) verify_argv = command_argv(args.verify_command, item_id=item_id) verify_env = {**os.environ, "LOOP_ITEM_ID": item_id} verify_result = subprocess.run(verify_argv, check=False, env=verify_env, timeout=args.command_timeout) except subprocess.TimeoutExpired: append_receipt( args.state, { "id": item_id, "attempt": attempt, "status": "retry", "reason": f"agent or verifier exceeded {args.command_timeout}s timeout", "timestamp": utc_now(), }, ) print( f"[queue] {item_id}: command exceeded {args.command_timeout}s timeout", file=sys.stderr, ) continue except OSError as error: append_receipt( args.state, { "id": item_id, "attempt": attempt, "status": "escalated", "reason": f"command could not start: {error}", "timestamp": utc_now(), }, ) print(f"[queue] {item_id}: command could not start: {error}", file=sys.stderr) return 3 status = "completed" if agent_result.returncode == 0 and verify_result.returncode == 0 else "retry" append_receipt( args.state, { "id": item_id, "attempt": attempt, "status": status, "agent_exit": agent_result.returncode, "verify_exit": verify_result.returncode, "timestamp": utc_now(), }, ) if status == "completed": print(f"[queue] {item_id}: verified", file=sys.stderr) break else: append_receipt( args.state, { "id": item_id, "attempt": args.max_retries, "status": "escalated", "reason": "retry budget exhausted", "timestamp": utc_now(), }, ) print(f"[queue] {item_id}: retry budget exhausted; escalating", file=sys.stderr) return 2 return 0 if __name__ == "__main__": raise SystemExit(main())