# MCP Billing Spec v1

**An open standard for billing, metering, receipts, verification, and dispute resolution in MCP tool ecosystems.**

[![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)
[![Spec Version](https://img.shields.io/badge/spec-v1.0-blue)](https://noui.bot/specs/mcp-billing-v1)
[![Reference Implementation](https://img.shields.io/badge/implementation-live-green)](https://noui.bot/docs/bazaar)

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## Why This Exists

There are 10,000+ MCP servers but most are hobby-quality because developers can't earn from them. Multiple companies are building billing solutions independently with incompatible schemas. This fragmentation hurts everyone:

- **Agents** must learn different billing APIs per provider
- **Providers** can't switch billing platforms without rewriting integrations
- **Platforms** compete on implementation details instead of value

This spec creates a common language for MCP billing.

## Quick Start

**Want to monetize your MCP server?** → [Provider Quickstart Guide](https://noui.bot/docs/guides/provider-quickstart) (5 minutes)

**Want to use paid MCP tools?** → [Consumer Quickstart](https://noui.bot/docs/quickstart) (3 minutes)

**Want to implement the spec?** → Read [mcp-billing-v1.md](./mcp-billing-v1.md)

## What It Covers

| Section | Description |
|---------|-------------|
| **Meter Events** | Standard schema for recording tool invocations |
| **Signed Receipts** | HMAC-SHA256 tamper-proof proof of every call |
| **Pricing Declarations** | How providers declare per-call and per-token pricing |
| **Verification Levels** | 4-tier provider verification (unverified → email → domain → code) |
| **Dispute Resolution** | Filing, status flow, resolution types |
| **Trust Scores** | Composite scoring from verification + SLA + disputes |

## Read the Spec

📄 **[mcp-billing-v1.md](./mcp-billing-v1.md)** — The full specification

🌐 **[noui.bot/specs/mcp-billing-v1](https://noui.bot/specs/mcp-billing-v1)** — Web version

## Reference Implementation

The [Agent Bazaar](https://noui.bot) at noui.bot is the reference implementation:

- **API:** `https://noui.bot/api/v1` (v0.4.0)
- **Provider Guide:** [noui.bot/docs/guides/provider-quickstart](https://noui.bot/docs/guides/provider-quickstart)
- **SDK:** `npm install @forthebots/bazaar-sdk`
- **OpenAPI:** `https://noui.bot/api/openapi.json`
- **Source:** [github.com/TombStoneDash/noui-bot](https://github.com/TombStoneDash/noui-bot)

### Key Features

- **Per-call billing** with sub-cent precision ($0.001 minimum)
- **90% revenue share** for providers (10% platform fee)
- **Signed receipts** (HMAC-SHA256) on every transaction
- **Trust scores** with verified provider badges
- **Dispute resolution** with full status flow
- **Zero code changes** — proxy to existing MCP servers

## Competitive Landscape

See how Agent Bazaar compares to other approaches: [noui.bot/docs/compare](https://noui.bot/docs/compare)

| Platform | Status | Trust Layer | Open Standard |
|----------|--------|-------------|---------------|
| **Agent Bazaar** | Live | ✅ v0.4.0 | ✅ This spec |
| xpay | Live | ❌ | ❌ |
| TollBit | Pre-launch | ❌ | ❌ |
| MCP Hive | Pre-launch (Mar 8) | ❌ | ❌ |

## For Other Billing Providers

This spec is designed to be implementable by anyone — including our competitors. If you're building MCP billing (xpay, TollBit, MCP Hive, or something new), you can:

1. **Implement the receipt schema** — agents get consistent billing experiences regardless of provider
2. **Use the verification levels** — a shared trust vocabulary for the ecosystem
3. **Adopt the dispute schema** — standard resolution flow across platforms
4. **Reference this spec** — and contribute to making it better

We'd rather be the reference implementation of a universal standard than a walled garden.

## Contributing

- Open an issue for spec feedback, clarifications, or proposed changes
- PRs welcome for typos, examples, and additional appendices
- Major schema changes should go through an issue discussion first

## License & Patent Pledge

This specification is released under MIT. No contributor may assert patents against implementations of this specification. This commitment is irrevocable.

Copy it. Fork it. Implement it. That's the point.

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