multi-agent coordination: Avoiding Agent Ping-Pong

# runtime/budget.py
from dataclasses import dataclass

@dataclass
class RunBudget:
    max_rounds: int = 4
    max_tokens: int = 200_000
    max_wall_s: int = 900
    tokens_used: int = 0
    rounds: int = 0

    def charge(self, tokens: int):
        self.tokens_used += tokens
        if self.tokens_used > self.max_tokens:
            raise RuntimeError("budget_tokens_exhausted")

    def tick_round(self):
        self.rounds += 1
        if self.rounds > self.max_rounds:
            raise RuntimeError("budget_rounds_exhausted")

def oscillating(history: list[str]) -> bool:
    if len(history) < 4:
        return False
    # ✅ same reject fingerprint twice in a row pair
    return history[-1] == history[-3] and history[-2] == history[-4]

// gates/human.ts
export type Gate = { kind: "continue" } | { kind: "human"; brief: string };

export function afterCritic(rounds: number, verdict: { decision: string; evidence: string[] }): Gate {
  if (verdict.decision === "ACCEPT") return { kind: "continue" };
  if (rounds >= 3) {
    return {
      kind: "human",
      brief: `Stuck after ${rounds} rounds.\nEvidence:\n- ${verdict.evidence.join("\n- ")}`,
    };
  }
  return { kind: "continue" };
}