Per-call billing and metering proxy for MCP tool servers.
MCP Billing Spec v1
An open standard for billing, metering, receipts, verification, and dispute resolution in MCP tool ecosystems.
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 (5 minutes)
Want to use paid MCP tools? → Consumer Quickstart (3 minutes)
Want to implement the spec? → Read 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 — The full specification
🌐 noui.bot/specs/mcp-billing-v1 — Web version
Reference Implementation
The Agent Bazaar at noui.bot is the reference implementation:
- API:
https://noui.bot/api/v1(v0.4.0) - Provider Guide: 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
Key Features
- Per-call billing with sub-cent precision ($0.001 minimum)
- 82% revenue share for providers (18% 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
| 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:
- Implement the receipt schema — agents get consistent billing experiences regardless of provider
- Use the verification levels — a shared trust vocabulary for the ecosystem
- Adopt the dispute schema — standard resolution flow across platforms
- 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.
Built by TombStone Dash LLC · San Diego, CA One human, one AI. The void is open.
Configuration
{"mcpServers": {"agent-bazaar": {"command": "npx", "args": ["@forthebots/bazaar-sdk"]}}}