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io.github.Syronius/cryptair-mcp-server

Tamper-evident attestation tools for AI agents — on-chain receipts on Hedera Hashgraph mainnet.

Open source Open in the app JSON README (API)

About

Tamper-evident attestation tools for AI agents — on-chain receipts on Hedera Hashgraph mainnet.

Details

Kind
MCP servers
Topic
No topic detected
Publisher
syronius
Origin
official
Category
ferramentas
Transport
local
Version
0.1.1
Last push
2026-05-08T20:37:17Z
Repository state
ativo
Language
JavaScript
License
MIT
Added
2026-08-29 03:02:16
Updated
2026-08-29 03:02:16
Origin id
io.github.Syronius/cryptair-mcp-server

README

# Cryptair MCP Server

Cryptographic attestation for AI agents, exposed as native [MCP](https://modelcontextprotocol.io) tools.

Lets any MCP-capable agent (Claude Desktop, Cursor, Cline, Windsurf, Zed, …) prove agreements, certify documents, and verify counterparty claims with on-chain receipts on [Hedera Hashgraph](https://hedera.com). Works zero-config out of the box: agents can self-register and start using attestation immediately, with no email verification or human-in-the-loop signup.

## What It Does

Cryptair lets two agents (or an agent and a human) prove they agreed on the same digital artifact at a specific moment. Every confirmed agreement is written as a SHA-256 hash to Hedera Hashgraph, producing a permanent, third-party-verifiable receipt.

This MCP server exposes six tools that map cleanly to how agents think:

| Tool | When to call |
|------|--------------|
| `certify_document` | "I want to prove this file existed at this moment." |
| `verify_document` | "Has this document been attested before? Is it tampered?" |
| `initiate_attestation` | "I want my counterparty to confirm they have the same document I do." |
| `submit_attestation` | "I received an attestation link from someone — confirm I have the matching file." |
| `check_attestation` | "What's the status of this attestation session?" |
| `register_agent` | "Create a Cryptair account for me so I can authenticate." |

## Install

```bash
npm install -g @cryptair/mcp-server
```

Or run directly via `npx` (no install needed):

```bash
npx -y @cryptair/mcp-server
```

## Configuration

### Claude Desktop

Edit `~/Library/Application Support/Claude/claude_desktop_config.json` (macOS) or `%APPDATA%\Claude\claude_desktop_config.json` (Windows):

```json
{
  "mcpServers": {
    "cryptair": {
      "command": "npx",
      "args": ["-y", "@cryptair/mcp-server"]
    }
  }
}
```

### Cursor

Edit `~/.cursor/mcp.json`:

```json
{
  "mcpServers": {
    "cryptair": {
      "command": "npx",
      "args": ["-y", "@cryptair/mcp-server"]
    }
  }
}
```

### Cline / Windsurf / Zed

All MCP-capable clients use the same config shape. Point them at `npx -y @cryptair/mcp-server`.

### Optional: Pre-configure Credentials

If you already have a Cryptair API key, you can supply it via env so the agent skips registration:

```json
{
  "mcpServers": {
    "cryptair": {
      "command": "npx",
      "args": ["-y", "@cryptair/mcp-server"],
      "env": {
        "CRYPTAIR_API_KEY": "ctr_live_..."
      }
    }
  }
}
```

Otherwise, the agent will call `register_agent` the first time it needs authentication, and the API key is silently stored at `~/.cryptair/credentials.json` for future use.

## Example Agent Prompts

After installing, try prompts like:

> "Certify the contents of `~/Documents/proposal-v3.pdf` so we have a timestamped receipt."

> "Send `~/Documents/contract.pdf` to Acme Corp and get them to formally acknowledge receipt — generate the link."

> "Acme sent me this Cryptair link: `https://www.cryptair.io/attest/abc...?token=xyz`. Confirm `~/Downloads/contract.pdf` matches what they sent."

> "What's the status of attestation session `abc-123`?"

The agent will pick the right tool and handle credential bootstrapping automatically.

## How Attestation Works

**Single-party (`certify_document`)**

1. The MCP server hashes the file locally with SHA-256.
2. The hash is sent to Cryptair, which writes it to a Hedera Consensus Service topic.
3. You get back a Hedera transaction ID, consensus timestamp, and a public certificate URL.
4. Anyone can verify by re-hashing the file and calling `verify_document` — the file content never has to leave your machine.

**Two-party (`initiate_attestation` + `submit_attestation`)**

1. Agent A initiates with a document hash and counterparty name. Cryptair returns a shareable URL.
2. Agent A sends the URL to Agent B via any channel (email, Slack, etc.).
3. Agent B opens the URL and submits the file *they* have. Their MCP server hashes it locally.
4. Cryptair compares hashes server-side:
   - **Match** → both parties' agreement is written to Hedera. Permanent record.
   - **Mismatch** → tamper event is written to Hedera. Both parties are notified.

Agent B does **not** need a Cryptair account to participate. If Agent B supplies an email when submitting, an account is auto-provisioned for them and the API key is silently persisted by their MCP server — so they can initiate their own attestations later without any signup friction.

## Why MCP, Not Skills

This server is cross-vendor by design. Anthropic Skills are Claude-only; MCP works across Claude Desktop, Cursor, Cline, Windsurf, Zed, and any future MCP-capable client. One install, every agent ecosystem.

## Environment Variables

| Variable | Purpose | Default |
|---------|---------|---------|
| `CRYPTAIR_API_KEY` | Pre-configured API key. Skips `register_agent`. | (none) |
| `CRYPTAIR_EMAIL` | Email used for `submit_attestation` auto-provisioning if omitted from the call. | (none) |
| `CRYPTAIR_BASE_URL` | API base URL. Override for self-hosted or staging. | `https://www.cryptair.io` |

## Development

```bash
git clone https://github.com/Syronius/cryptair-mcp-server
cd mcp-server
npm install
npm run build
npm start
```

The server speaks JSON-RPC over stdio. To test manually, send `tools/list` to confirm all six tools are registered.

## Free Tier & Pricing

The Cryptair free tier currently lets every account originate a small number of attestations per month. Counterparty completion (`submit_attestation`) is always free. Heavy users can top up with prepaid credits — see [cryptair.io/pricing](https://www.cryptair.io) for details.

## License

MIT

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