Orphograph MCP server

A single-file Model Context Protocol server that lets a Claude / Claude Code / Cursor / any-MCP-host instance anchor files to the Bitcoin chain via Orphograph without the file ever leaving the user's machine.

mcp-name: io.github.Orphograph/orphograph

• License: MIT
• Dependencies: Python ≥ 3.9 standard library only. No pip install required.
• Lines of code: ~310, single file.
• Protocol: MCP 2024-11-05 over stdio.

Install

Save the script anywhere:

curl -sSL https://orphograph.com/mcp/orphograph_mcp.py -o ~/bin/orphograph_mcp.py

Then register it with your MCP host.

Claude Desktop (~/Library/Application Support/Claude/claude_desktop_config.json)

{
  "mcpServers": {
    "orphograph": {
      "command": "python3",
      "args": ["/Users/YOU/bin/orphograph_mcp.py"],
      "env": {
        "ORPHO_API_KEY": ""
      }
    }
  }
}

Claude Code

claude mcp add orphograph python3 /Users/YOU/bin/orphograph_mcp.py

Or edit ~/.claude/settings.json and add the same mcpServers block.

Cursor (~/.cursor/mcp.json)

{
  "mcpServers": {
    "orphograph": {
      "command": "python3",
      "args": ["/Users/YOU/bin/orphograph_mcp.py"],
      "env": {
        "ORPHO_API_KEY": ""
      }
    }
  }
}

Tools exposed

Tool	Purpose	Auth
orphograph_anchor_file(path)	Hash a local file and register the fingerprint on Bitcoin.	Optional API key
orphograph_anchor_folder(path)	Hash a whole folder into an RFC-6962 Merkle tree and anchor one root covering every file.	Optional API key
orphograph_anchor_output(text, …)	Hash generated output (an agent result, a transcript) in-process and anchor it. Accepts an optional zk_proof.	Optional API key
orphograph_verify_receipt(receipt_id)	Look up what the office recorded for a receipt. A lookup — it does NOT consult the chain; run ots verify for that.	None
orphograph_verify_lineage(receipt_id)	Walk an edit-lineage chain back through its committed parents.	None
orphograph_list_vault(limit?)	List the subscriber's receipts.	API key required

Privacy contract

• The file body never leaves the device.
• The script computes SHA-256 + SHA-512 in-process and transmits only those fingerprints to https://orphograph.com/api/anchor.
• The script makes no network call until a tool is explicitly invoked by the host.
• File reads stream in 1 MB chunks; large files do not load into memory.

Configuration

Environment variable	Purpose
ORPHO_API_KEY	Optional. Issued from orphograph.com/account.html. Without it, the install is rate-limited to the free tier (3 anchors per 24 hours).
ORPHO_BASE_URL	Optional. Defaults to https://orphograph.com. Override for testing or self-hosted instances.

Tiers and limits

Tier	Cap	Price
Free	3 anchors / 24h	$0
Writer Pack	10 anchors, never expires	$19 one-time
Pack of Fifty	50 anchors, never expires	$29 one-time
Standing Order	Unrestricted anchoring	$9 / month

Verification

The MCP server only issues calls. Every receipt it produces can be checked without this office, in two independent steps:

1. Structure — the open-source verifier at github.com/Orphograph/Orphograph re-derives the hashes and checks the receipt offline. It makes no network calls of its own.
2. Chain — the OpenTimestamps client (ots verify) confirms the commitment actually landed in a Bitcoin block. The bundled verifier will invoke it for you when passed --ots.

Only step 2 consults Bitcoin.

Reporting issues

Open an issue at the public repo, or write to [email protected].