Cryptair MCP Server

Name: Cryptair MCP Server
Author: Syronius

by Syroniusversion 0.1.1i★ –iRuns on your computer

Registry nameio.github.Syronius/cryptair-mcp-server

Install

Overview

Description from the maker (original English)

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

PopNx MCP’s three pillars

These three are never merged into one score: opinions, measurements and popularity are different things.

User voiceiNo reviews yetReviews open together with accounts in a later step
Our basic checksi1 of 1 passedChecked from public information; code not scanned yet
UsageiNot measured yet★ –

What you can do with it

We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.

Connection: Runs on your computer
Transport: stdio
Category: Other
You need to fill in: CRYPTAIR_API_KEY

Install

Pick the AI app you use, then copy the settings.

Before you install

Basic checks: 1 of 1 passed
Runs on your computer with your user’s permissions (files, network, apps).
You fill in yourself: CRYPTAIR_API_KEY, CRYPTAIR_EMAIL, CRYPTAIR_BASE_URL

Values marked secret are keys to your account. Never share them or paste them into a chat.

You need

npmNode.js installed (for the npx command)

Which app do you use?

ClaudeClaude CodeCursorVS CodeChatGPT

Pick your app above. We remember it, so next time the button says “Install in …”.

Open Claude Desktop → Settings → Developer → Edit Config, and paste this into claude_desktop_config.json

{
  "mcpServers": {
    "cryptair": {
      "command": "npx",
      "args": [
        "-y",
        "@cryptair/mcp-server"
      ],
      "env": {
        "CRYPTAIR_API_KEY": "your-value",
        "CRYPTAIR_EMAIL": "your-value",
        "CRYPTAIR_BASE_URL": "your-value"
      }
    }
  }
}

Run this in your terminal

claude mcp add cryptair --env CRYPTAIR_API_KEY=your-value --env CRYPTAIR_EMAIL=your-value --env CRYPTAIR_BASE_URL=your-value -- npx -y @cryptair/mcp-server

Fill in the empty values before running it.

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

{
  "mcpServers": {
    "cryptair": {
      "command": "npx",
      "args": [
        "-y",
        "@cryptair/mcp-server"
      ],
      "env": {
        "CRYPTAIR_API_KEY": "your-value",
        "CRYPTAIR_EMAIL": "your-value",
        "CRYPTAIR_BASE_URL": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "cryptair": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "@cryptair/mcp-server"
      ],
      "env": {
        "CRYPTAIR_API_KEY": "your-value",
        "CRYPTAIR_EMAIL": "your-value",
        "CRYPTAIR_BASE_URL": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

This one runs on your computer, and ChatGPT can only connect to servers on the internet. Pick another app.

Your choice stays on this device in a cookie; no account needed.

Values you fill in

CRYPTAIR_API_KEY secret env
Optional. Pre-configured Cryptair API key. If unset, the agent can call register_agent at runtime to self-register and the key is silently stored at ~/.cryptair/credentials.json.
CRYPTAIR_EMAIL env
Optional. Email used as fallback when submit_attestation auto-provisions a counterparty account.
CRYPTAIR_BASE_URL env
Optional. Override the API base URL for self-hosted or staging environments. Defaults to https://www.cryptair.io.

These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

What it can do

Runs on your computer; the tool list appears in your AI app after you install it.

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 7, 2026

✓ Pass
Maker matches the repo
The registry name was verified with the GitHub account Syronius, which owns the repo
… Not checked yet
Still maintained
We have not read this repo from GitHub yet
… Not checked yet
Has a licence
We have not read this repo from GitHub yet
– Not applicable
Endpoint responds
This one runs on your computer; there is no internet endpoint
– Not applicable
Sign-in with OAuth
Runs on your computer and uses local settings instead
… Not checked yet
No hidden instructions in tool descriptions
Runs on your computer; we can only read tool lists from internet endpoints

Compared with others in Otheri

More stars than 0% of the other 32683 servers in this category
Published to the registry more recently than 8% of the other 32683 servers in this category
Basic checks equal to or better than 100% of the other 32683 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Common questions

Is Cryptair MCP Server safe?

It passed 1 of 1 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.

What keys or codes does it need?

You need to fill in: CRYPTAIR_API_KEY

Does it run on my computer or in the cloud?

It runs on your computer. Your AI app starts it when needed, and data does not pass through the maker’s servers (unless it calls an online service itself).

Is it still maintained?

The GitHub repo last changed –, and the latest version (0.1.1) reached the registry 6 months ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. You also need Node.js on your computer.

What can I use instead?

In the same category: Spec Driven Development, Remote Desktop Commander, MCP Server Autocad Lisp Helper

Alternatives

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README from the maker

Open the README

Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.

Cryptair MCP Server

Cryptographic attestation for AI agents, exposed as native MCP 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. 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

npm install -g @cryptair/mcp-server

Or run directly via npx (no install needed):

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):

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

Cursor

Edit ~/.cursor/mcp.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:

"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`)

The MCP server hashes the file locally with SHA-256.
The hash is sent to Cryptair, which writes it to a Hedera Consensus Service topic.
You get back a Hedera transaction ID, consensus timestamp, and a public certificate URL.
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`)

Agent A initiates with a document hash and counterparty name. Cryptair returns a shareable URL.
Agent A sends the URL to Agent B via any channel (email, Slack, etc.).
Agent B opens the URL and submits the file *they* have. Their MCP server hashes it locally.
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

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 for details.

License

MIT

Cryptair MCP Server

Overview

PopNx MCP’s three pillars

What you can do with it

Install

Before you install

Values you fill in

What it can do

Basic checksi

Maker matches the repo

Still maintained

Has a licence

Endpoint responds

Sign-in with OAuth

No hidden instructions in tool descriptions

Compared with others in Otheri

Common questions

Alternatives

Spec Driven Development

Remote Desktop Commander

MCP Server Autocad Lisp Helper

README from the maker

Cryptair MCP Server

What It Does

Install

Configuration

Claude Desktop

Cursor

Cline / Windsurf / Zed

Optional: Pre-configure Credentials

Example Agent Prompts

How Attestation Works

Why MCP, Not Skills

Environment Variables

Development

Free Tier & Pricing

License