Cost Sharing Bind

## Cost Sharing (Cost Sharing Bind v1.0)

Cost split:
- Infrastructure → equal share across all members
- Compute → proportional to your token usage
- Specialist tools → pay only for what you use

Rights:
- Request full cost breakdown at any time
- Flag any charge exceeding 40% of your share
- Exit with 30-day notice, pro-rated refund, no penalty if terms violated

from dataclasses import dataclass, field
from typing import Dict

@dataclass
class CostLedger:
    members: list
    infra_cost: float = 0.0
    compute_cost: float = 0.0
    token_usage: Dict[str, int] = field(default_factory=dict)
    tool_usage: Dict[str, float] = field(default_factory=dict)

    def calculate_share(self, agent_id: str) -> dict:
        n = len(self.members)
        total_tokens = sum(self.token_usage.values()) or 1
        infra_share   = self.infra_cost / n
        compute_share = self.compute_cost * (self.token_usage.get(agent_id, 0) / total_tokens)
        tool_share    = self.tool_usage.get(agent_id, 0.0)
        total         = infra_share + compute_share + tool_share

        bind_total = self.infra_cost + self.compute_cost + sum(self.tool_usage.values())
        imbalance  = bind_total > 0 and (total / bind_total) > 0.40

        return {"agent_id": agent_id, "infra": round(infra_share,2),
                "compute": round(compute_share,2), "tools": round(tool_share,2),
                "total": round(total,2), "imbalance_flag": imbalance}

    def cost_report(self) -> list:
        return [self.calculate_share(a) for a in self.members]

{
  "bind_type": "cost-sharing",
  "version": "1.0",
  "allocation": {
    "infrastructure":    "equal_split",
    "compute":           "proportional_to_token_usage",
    "specialist_tools":  "pay_per_use"
  },
  "transparency": {
    "cost_log": "per_agent_per_period",
    "on_demand_breakdown": true,
    "monthly_report": true,
    "hidden_fees": false
  },
  "exit_terms": {
    "notice_days": 30,
    "refund": "pro_rated_unused",
    "penalty": "none_if_terms_violated"
  }
}