Summary
This is the reference MCP server for the Open Primitive Protocol, a spec for wrapping data in verifiable envelopes with provenance chains and Ed25519 signatures. The 33 tools connect to 30 US federal data domains across agencies like FDA, EPA, and USGS. Every response includes freshness timestamps, confidence scores, citations, and cryptographic proofs. You'd reach for this when you need Claude to pull authoritative government data with full audit trails, whether that's drug adverse events from FAERS, EPA air quality readings, or USGS earthquake reports. The protocol itself is MIT licensed and designed for any data provider to implement, but this server gives you immediate access to federal datasets with Level 3 conformance.
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Open Primitive Protocol (OPP)
The data layer of the agent internet.
OPP defines how data providers make their data agent-consumable, verifiable, and discoverable. Three components: provider manifest, response envelope, query interface.
The Problem
Agents get data naked. No provenance. No freshness guarantee. No confidence score. No way to verify the source. The agent internet is missing its data envelope.
The Protocol
| Component | What it does |
|---|---|
Manifest (/.well-known/opp.json) | Declares what data a provider serves, how fresh it is, how to verify it |
| Response Envelope | Every response carries domain, source, freshness, confidence, citation, Ed25519 signature |
| Query Interface | Standardized HTTP GET endpoints with predictable parameters |
Conformance Levels
- Level 1 (Basic): Manifest + envelope with domain/source/freshness
- Level 2 (Cited): Level 1 + confidence scores + citations
- Level 3 (Verified): Level 2 + Ed25519 cryptographic proof
Reference Implementation
Live at api.openprimitive.com. 16 US federal data domains across 11 agencies. Level 3 compliant — every response is signed.
curl https://api.openprimitive.com/v1/drugs?name=aspirin
# Returns OPP envelope with proof.type: "DataIntegrityProof"
Quick Start
Use data from an OPP provider:
const res = await fetch('https://api.openprimitive.com/v1/drugs?name=aspirin');
const data = await res.json();
console.log(data.citations.statement);
// "According to FDA FAERS, aspirin has 601,477 reported adverse events"
Implement OPP for your own data:
// 1. Create /.well-known/opp.json (see spec)
// 2. Wrap responses in the OPP envelope
// 3. Optionally sign with Ed25519
Specification
Full spec: openprimitive.com/protocol.html
Detailed spec: api.openprimitive.com/spec.html
SDK
sdk/opp-client.js— Client library for consuming OPP providerssdk/opp-provider.js— Helper for implementing OPPsdk/opp-validator.js— Validate OPP conformance
MCP Server
13 tools for Claude, Cursor, and MCP-compatible agents:
npx open-primitive-mcp
Links
License
MIT
Featured
Keep your Mac awake while Claude Code and 40+ AI agents run. Sleeps when they're idle.
One time payment $9 →Integrate web data into your AI product. One API to scrape website & brand data.
Get API Key Now →Agent, run crypto. Access onchain data & trade routes via 1inch.
Install now →On Capafy, your Skill runs online 24/7 as an agent product, and you get paid every time someone uses it.
Start earning →Categories
Registryactive
Packageopen-primitive-mcp
TransportSTDIO
UpdatedApr 18, 2026
