MCP Integration Kit
The MCP integration kit provides everything needed to add verifiable interaction evidence to MCP tool responses.
What you get
- Receipt attachment via
_metafields in JSON-RPC responses - Receipt extraction and integrity verification at the client side
- 5 built-in MCP tools via
@peac/mcp-server: verify, inspect, decode, issue, create bundle - Compatible with Claude Desktop, Cursor, Continue.dev, and any MCP client
Quick start
Terminal
# Try the MCP server immediately
npx -y @peac/mcp-server --help
# Or install the mapping package for custom integration
pnpm add @peac/mappings-mcp
Key concepts
Evidence carrier placement: Receipts travel in _meta using two reserved keys:
| Key | Value | Purpose |
|---|---|---|
org.peacprotocol/receipt_ref | sha256:<hex> | Content-addressable receipt reference |
org.peacprotocol/receipt_jws | Compact JWS | The signed receipt |
Transport limits: 64 KB embed limit for MCP/JSON-RPC responses.
Integrity: receipt_ref = sha256(receipt_jws) verified at extraction time.
Resources
MCP Registry
PEAC MCP Server is published and discoverable on the official MCP Registry as io.github.peacprotocol/peac.