Doichain

Official13 tools

by neubuot · Python

Proof of existence, names and chain data of the Doichain blockchain for AI agents

MCP Server: io.github.neubuot/doichain

The MCP server io.github.neubuot/doichain provides “proof of existence” along with names and chain data for the Doichain blockchain, intended for use by AI agents. Its scope is described as supplying these blockchain-related datasets rather than performing unrelated tasks.

🛠️ Key Features

Proof of existence
Names data for Doichain
Chain data for Doichain blockchain
Designed for AI agents

🚀 Use Cases

Supplying existence proofs to AI agents
Retrieving and using Doichain names data
Accessing Doichain chain data for agent workflows

⚡ Developer Benefits

Clear, blockchain-focused data sources (proof, names, chain data)
Developer-visible purpose: “for AI agents” and Doichain context

⚠️ Limitations

Only Doichain blockchain “proof of existence, names and chain data” are described; other capabilities are not provided in the source data.

Topics

ai-agentsblockchainclaudedoichainllm-toolsmcpmcp-servermodel-context-protocolnamecoinnotaryproof-of-existencepythonstreamable-httptimestamping

Captured live from the server via tools/list.

get_chain_status

Current state of the Doichain network as seen by the node behind this server: block height, sync state, time of the last block, fork check, node version, peers, mempool size and whether public anchoring is available.

Parameters

No parameters.

Raw schema

{
  "type": "object",
  "properties": {},
  "title": "get_chain_statusArguments"
}

hash_text

Compute the SHA-256 digest of a short text (UTF-8) on the server, for example to anchor a statement or a message with anchor_proof. The text is sent to the server but not stored or logged. For files and for confidential texts compute the hash locally instead (sha256sum file, or Get-FileHash -Algorithm SHA256).

Parameters1

text

string

required

Text to hash, encoded as UTF-8 exactly as given (whitespace and line breaks count), at most 40,000 characters

Raw schema

{
  "type": "object",
  "properties": {
    "text": {
      "description": "Text to hash, encoded as UTF-8 exactly as given (whitespace and line breaks count), at most 40,000 characters",
      "maxLength": 40000,
      "title": "Text",
      "type": "string"
    }
  },
  "required": [
    "text"
  ],
  "title": "hash_textArguments"
}

check_proof

Check whether a SHA-256 hash is anchored on the Doichain (name poe/<sha256>) and since when. Returns status (confirmed, pending, expired, unknown) and at the top level block height, block time, transaction and links of the first anchoring, which is the proof time. If the name was updated later or registered again after it expired (possibly by someone else), that registration is reported separately in latest_registration with its own holder and record, which are not part of the original proof. A confirmed or expired proof shows that a document with exactly this hash existed no later than the block time, not who submitted it.

Parameters1

sha256

string

required

SHA-256 digest of the document, 64 hexadecimal characters (a sha256: or 0x prefix is accepted)

Raw schema

{
  "type": "object",
  "properties": {
    "sha256": {
      "description": "SHA-256 digest of the document, 64 hexadecimal characters (a sha256: or 0x prefix is accepted)",
      "maxLength": 100,
      "title": "Sha256",
      "type": "string"
    }
  },
  "required": [
    "sha256"
  ],
  "title": "check_proofArguments"
}

anchor_proof

Anchor a SHA-256 hash on the Doichain as a tamper-evident timestamp (proof of existence, name poe/<sha256>). Free for users, limited per IP address and day (see get_anchoring_quota). Confirms with the next block, usually within 10 minutes, then check_proof returns block height and time. If the hash is already anchored or pending, the existing proof is returned instead of creating a second one. If an earlier proof of the hash has expired, it stays valid and is returned with expired true. Nothing is registered unless reanchor_expired is true. Only the hash and the optional note and file name become public, never the document itself. The operator of this server pays for the name and holds it. The proof shows that a document with this hash existed no later than the block time, not who submitted it.

Parameters4

sha256	string	required	SHA-256 digest of the document, 64 hexadecimal characters, computed from the actual file. Never guess it and never send the document
note	any	optional	Optional public note (max 160 characters), stored on the blockchain forever. No personal data, no secrets
filename	any	optional	Optional public file name (max 80 characters), stored forever. Only set it when the user explicitly wants the name public
reanchor_expired	boolean	optional	Only set to true when an earlier proof of this hash has expired and the user explicitly wants an additional, later registration. The original anchoring stays the proof time. The new registration adds a later timestamp and replaces the public note and holder of the name. Default false

Raw schema

{
  "type": "object",
  "properties": {
    "sha256": {
      "description": "SHA-256 digest of the document, 64 hexadecimal characters, computed from the actual file. Never guess it and never send the document",
      "maxLength": 100,
      "title": "Sha256",
      "type": "string"
    },
    "note": {
      "anyOf": [
        {
          "maxLength": 160,
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "description": "Optional public note (max 160 characters), stored on the blockchain forever. No personal data, no secrets",
      "title": "Note"
    },
    "filename": {
      "anyOf": [
        {
          "maxLength": 80,
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "description": "Optional public file name (max 80 characters), stored forever. Only set it when the user explicitly wants the name public",
      "title": "Filename"
    },
    "reanchor_expired": {
      "default": false,
      "description": "Only set to true when an earlier proof of this hash has expired and the user explicitly wants an additional, later registration. The original anchoring stays the proof time. The new registration adds a later timestamp and replaces the public note and holder of the name. Default false",
      "title": "Reanchor Expired",
      "type": "boolean"
    }
  },
  "required": [
    "sha256"
  ],
  "title": "anchor_proofArguments"
}

get_anchoring_quota

How many proofs can still be anchored today (UTC day) within the free public quota for the caller's IP address. Hosted chat apps connect from their own servers, so their users share one quota. Callers that send their own API key in the X-API-Key header have no quota.

Parameters

No parameters.

Raw schema

{
  "type": "object",
  "properties": {},
  "title": "get_anchoring_quotaArguments"
}

lookup_name

Read the current value, owner address and expiry of a Doichain name. Unregistered names come back with exists false and status not_registered (the name is free). Expired names have status expired and the real expiry date.

Parameters1

name

string

required

Full name including namespace, for example poe/<sha256>, d/example or id/alice

Raw schema

{
  "type": "object",
  "properties": {
    "name": {
      "description": "Full name including namespace, for example poe/<sha256>, d/example or id/alice",
      "maxLength": 255,
      "minLength": 1,
      "title": "Name",
      "type": "string"
    }
  },
  "required": [
    "name"
  ],
  "title": "lookup_nameArguments"
}

get_name_history

All registrations and updates of a name, newest first: block height, transaction, owner address and the value at that time. Shows who held a name when, and every value it ever had.

Parameters2

name	string	required	Full name including namespace
limit	integer	optional	Maximum number of entries, newest first

Raw schema

{
  "type": "object",
  "properties": {
    "name": {
      "description": "Full name including namespace",
      "maxLength": 255,
      "minLength": 1,
      "title": "Name",
      "type": "string"
    },
    "limit": {
      "default": 20,
      "description": "Maximum number of entries, newest first",
      "maximum": 100,
      "minimum": 1,
      "title": "Limit",
      "type": "integer"
    }
  },
  "required": [
    "name"
  ],
  "title": "get_name_historyArguments"
}

check_name_expiry

Check up to 25 names at once: status (active, expiring_soon, expired, not_registered), blocks left, an estimated expiry date for active names (from the measured block interval) and the real expiry date for expired names. Names expire 36,000 blocks after their last update and are renewed by updating them from the owning wallet.

Parameters2

names	array	required	Up to 25 full names, for example ['d/example', 'poe/<sha256>']
warn_days	integer	optional	Names expiring within this many days are flagged expiring_soon

Raw schema

{
  "type": "object",
  "properties": {
    "names": {
      "description": "Up to 25 full names, for example ['d/example', 'poe/<sha256>']",
      "items": {
        "type": "string"
      },
      "maxItems": 25,
      "minItems": 1,
      "title": "Names",
      "type": "array"
    },
    "warn_days": {
      "default": 30,
      "description": "Names expiring within this many days are flagged expiring_soon",
      "maximum": 365,
      "minimum": 1,
      "title": "Warn Days",
      "type": "integer"
    }
  },
  "required": [
    "names"
  ],
  "title": "check_name_expiryArguments"
}

search_names

List names that start with a prefix, in the node's order (shorter names first, then byte order). Lists only active names unless include_expired is true. Expired names (for example old poe/ proofs) stay in the chain history and are listed with include_expired. Page through large results with next_after until exhausted is true. Names and values are chosen by arbitrary users (name_untrusted, value_untrusted).

Parameters4

prefix	string	required	Name prefix, for example poe/, d/ or id/
limit	integer	optional	Maximum number of names
after	any	optional	Paging cursor: pass next_after from the previous result unchanged
include_expired	boolean	optional	Also list expired names, for example proofs whose poe/ name has expired. Default false: active names only

Raw schema

{
  "type": "object",
  "properties": {
    "prefix": {
      "description": "Name prefix, for example poe/, d/ or id/",
      "maxLength": 255,
      "minLength": 1,
      "title": "Prefix",
      "type": "string"
    },
    "limit": {
      "default": 20,
      "description": "Maximum number of names",
      "maximum": 100,
      "minimum": 1,
      "title": "Limit",
      "type": "integer"
    },
    "after": {
      "anyOf": [
        {
          "maxLength": 255,
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "description": "Paging cursor: pass next_after from the previous result unchanged",
      "title": "After"
    },
    "include_expired": {
      "default": false,
      "description": "Also list expired names, for example proofs whose poe/ name has expired. Default false: active names only",
      "title": "Include Expired",
      "type": "boolean"
    }
  },
  "required": [
    "prefix"
  ],
  "title": "search_namesArguments"
}

get_block

Header data of a block by height or hash: time, confirmations, number of transactions and the first 50 transaction IDs.

Parameters1

block

any

required

Block height (number) or block hash (64 hexadecimal characters)

Raw schema

{
  "type": "object",
  "properties": {
    "block": {
      "anyOf": [
        {
          "type": "integer"
        },
        {
          "type": "string"
        }
      ],
      "description": "Block height (number) or block hash (64 hexadecimal characters)",
      "title": "Block"
    }
  },
  "required": [
    "block"
  ],
  "title": "get_blockArguments"
}

get_transaction

A transaction with confirmations, block time, outputs (amount in DOI and address) and any name operation (name_doi, name_update, ...) it contains.

Parameters1

txid

string

required

Transaction ID, 64 hexadecimal characters

Raw schema

{
  "type": "object",
  "properties": {
    "txid": {
      "description": "Transaction ID, 64 hexadecimal characters",
      "maxLength": 100,
      "title": "Txid",
      "type": "string"
    }
  },
  "required": [
    "txid"
  ],
  "title": "get_transactionArguments"
}

get_address

Confirmed and unconfirmed balance of a Doichain address in DOI, optionally with its most recent transactions. Invalid addresses return an error with the reason.

Parameters3

address	string	required	Doichain address (M... or N..., 6..., or bech32 dc1q...)
include_history	boolean	optional	Also return the most recent transactions
history_limit	integer	optional	Number of recent transactions when include_history is true

Raw schema

{
  "type": "object",
  "properties": {
    "address": {
      "description": "Doichain address (M... or N..., 6..., or bech32 dc1q...)",
      "maxLength": 100,
      "minLength": 20,
      "title": "Address",
      "type": "string"
    },
    "include_history": {
      "default": false,
      "description": "Also return the most recent transactions",
      "title": "Include History",
      "type": "boolean"
    },
    "history_limit": {
      "default": 10,
      "description": "Number of recent transactions when include_history is true",
      "maximum": 50,
      "minimum": 1,
      "title": "History Limit",
      "type": "integer"
    }
  },
  "required": [
    "address"
  ],
  "title": "get_addressArguments"
}

verify_message

Check whether a message was signed with the private key of a Doichain address (signmessage format). Only legacy addresses (M... or N...) can sign messages, bech32 addresses (dc1q...) are not supported. Useful to confirm that a statement really comes from the holder of an address.

Parameters3

address	string	required	Legacy Doichain address (M... or N...) that supposedly signed the message
message	string	required	The exact signed text
signature	string	required	Signature in Base64

Raw schema

{
  "type": "object",
  "properties": {
    "address": {
      "description": "Legacy Doichain address (M... or N...) that supposedly signed the message",
      "maxLength": 100,
      "minLength": 20,
      "title": "Address",
      "type": "string"
    },
    "message": {
      "description": "The exact signed text",
      "maxLength": 10000,
      "title": "Message",
      "type": "string"
    },
    "signature": {
      "description": "Signature in Base64",
      "maxLength": 200,
      "minLength": 20,
      "title": "Signature",
      "type": "string"
    }
  },
  "required": [
    "address",
    "message",
    "signature"
  ],
  "title": "verify_messageArguments"
}

README.md13 KBView on GitHub

Doichain MCP logo

Doichain MCP Server

Tamper-evident timestamps for your AI agent.
Prove that a document already existed at a given time: anchor its hash on the Doichain (proof of existence), verify proofs and read names, blocks and addresses.
One URL, no account, no API key, no installation.

Python 3.11+ MCP 2024-11-05 to 2026-07-28

Quick start · Tools · How it works · Limits · Security · Tool reference · Self-hosting · Deutsch

Endpoint: https://doi-api.sendlabs.de/mcp · Streamable HTTP · stateless · no authentication required

The Doichain is a public blockchain with a built-in name-value store (a Namecoin descendant, merge-mined with Bitcoin). This server makes it usable for any agent that speaks the Model Context Protocol: Claude, ChatGPT, Cursor, VS Code Copilot and many more. Ask your agent in plain language, it picks the right tool itself:

"Anchor the hash of offer-2026.pdf on the Doichain." "Did this contract already exist before October 1?" "Are d/example or id/alice about to expire?" "How is the Doichain doing right now?"

Opening the endpoint in a browser shows the landing page with setup instructions.

Quick start

Claude Code

bash

claude mcp add --scope user --transport http doichain https://doi-api.sendlabs.de/mcp

Check with claude mcp list. Without --scope user the server only applies to the current project.

Claude (web and desktop)

Open Customize → Connectors and click +.
Choose Add custom connector, name it Doichain and paste https://doi-api.sendlabs.de/mcp.
In a chat, enable it via + → Connectors.

Custom connectors also work on the free plan (one connector). On Team and Enterprise an owner adds it in the organization settings.

ChatGPT

Turn on Settings → Security and login → Developer mode, then create an app under Plugins → + with the URL above and authentication None. Developer mode is available on the web for Plus, Pro, Business, Enterprise and Education.

Cursor

~/.cursor/mcp.json (all projects) or .cursor/mcp.json (one project):

json

{
  "mcpServers": {
    "doichain": { "url": "https://doi-api.sendlabs.de/mcp" }
  }
}

VS Code (Copilot agent mode)

.vscode/mcp.json:

json

{
  "servers": {
    "doichain": { "type": "http", "url": "https://doi-api.sendlabs.de/mcp" }
  }
}

Any other client

Setting	Value
URL	`https://doi-api.sendlabs.de/mcp`
Transport	Streamable HTTP (`http` / `streamable-http`), stateless, JSON responses
Authentication	none, optionally your own key in the `X-API-Key` header
Protocol versions	2024-11-05, 2025-03-26, 2025-06-18, 2025-11-25, 2026-07-28

Try it without an AI client using the MCP Inspector: npx @modelcontextprotocol/inspector, choose Streamable HTTP and enter the URL. A small Python example is in examples/check_proof.py.

Tools

Tool	What it does	Access
`anchor_proof`	Anchor the SHA-256 of a document as a tamper-evident timestamp (proof of existence, name `poe/<sha256>`). Already anchored hashes return the existing proof. An expired hash is only registered again with `reanchor_expired: true`.	writes
`check_proof`	Is this hash anchored, since when, in which block? Always reports the first anchoring and shows a later registration of the name separately.	reads
`hash_text`	SHA-256 of a short text (up to 40,000 characters), computed on the server, nothing stored.	server-side
`get_anchoring_quota`	Proofs still available today for the caller's IP address.	reads
`lookup_name`	Current value, owner and expiry of a name such as `d/example` or `id/alice`.	reads
`get_name_history`	Every registration and update of a name, newest first.	reads
`check_name_expiry`	Up to 25 names at once: active, expiring soon, expired or free, with dates.	reads
`search_names`	Names by prefix (for example all `poe/` proofs), with paging. Expired names with `include_expired`.	reads
`get_chain_status`	Block height, sync state, last block, fork check, average block interval.	reads
`get_block`	A block by height or hash.	reads
`get_transaction`	A transaction with outputs, addresses and name operations.	reads
`get_address`	Balance of an address, optionally with recent transactions.	reads
`verify_message`	Check a message signed with a Doichain address (legacy `M…`/`N…` addresses).	reads

All tools return structured JSON (structuredContent) and carry MCP tool annotations. Only anchor_proof is not read-only. Parameters, return fields and examples: docs/tools.md.

How a proof of existence works

sequenceDiagram
    participant U as You
    participant A as AI agent
    participant M as Doichain MCP server
    participant D as Doichain
    U->>A: "Anchor offer-2026.pdf"
    A->>A: sha256sum offer-2026.pdf (the file never leaves your machine)
    A->>M: anchor_proof(sha256)
    M->>D: name_doi poe/<sha256> = {"v":1,"alg":"sha256",...}
    D-->>M: transaction id (pending)
    M-->>A: txid, verify URL
    Note over D: next block, usually within 10 minutes
    U->>A: "Did this document exist before October 1?"
    A->>M: check_proof(sha256)
    M->>D: name_show / name_history
    M-->>A: confirmed, block 433,335, 2026-09-25 23:21 UTC

Only the hash, and optionally a public note or file name, goes on chain. A SHA-256 cannot be turned back into the document. Anyone can verify a proof later with check_proof or on verifile.it, and changing a single byte of the document produces a different hash.

What a proof shows, and for how long:

The timestamp is permanent. The anchoring transaction and its block time stay in the blockchain history for good.
The name is not. poe/<sha256> stays active for 36,000 blocks (about 250 days at ten minutes per block). After that anyone can register it again, with their own note and address. check_proof keeps reporting the first anchoring as the proof time and shows a later registration separately in latest_registration. anchor_proof does not register an expired hash again unless you ask for it with reanchor_expired, and search_names lists expired proofs with include_expired.
Existence, not authorship. A proof shows that a document with this hash existed no later than the block time. It does not show who submitted it. The hosted endpoint registers the names from the operator's wallet, which pays for them and holds them.

Agents need access to the file to hash it (Claude Code, Cursor, VS Code). In a plain chat, Verifile is the easiest way: drop the file, it is hashed in the browser and anchored with one click.

Limits and quotas

Limit	Value
Anchoring	free for users, 10 proofs per IP address per UTC day, at most 200 per day for all users together
Requests	10 per second per IP address (burst 40), JSON-RPC error `-32000` with `Retry-After: 1` when exceeded
Request size	256 KB, `hash_text` up to 40,000 characters
Reading and checking	unlimited within the request rate

Hosted chat apps (Claude on the web, ChatGPT) connect from their providers' data centers, so all their users share the quota of those addresses. For regular anchoring use a client that connects from your own machine (Claude Code, Cursor, VS Code) or ask DOI Labs for an own key. Anchoring pauses automatically when the operating balance of the node wallet falls below a reserve, reading keeps working.

Security and privacy

Hashes only. The server accepts no files. hash_text sees a short text and forgets it immediately.
No wallet functions. The server cannot send coins, change names or call node RPCs. Its only write operation is anchor_proof, for which the REST API registers the name from the operator's wallet. It runs as a separate service under its own system user, without read access to the API's key file, and may only open local connections.
Prompt injection protection. Names and values written to the chain by strangers are returned in fields ending in _untrusted together with a notice, and the server instructions tell agents to treat them as data only.
DNS rebinding protection. Host and Origin headers are validated.
No tracking. No cookies, no third-party resources on the landing page. Like any web server, IP addresses appear in access logs and count toward the daily quota. Content is not stored.

Found a vulnerability? Please use private vulnerability reporting, see SECURITY.md.

Protocol behavior

Streamable HTTP in stateless mode with JSON responses, so any number of workers can serve requests without session affinity.
POST /mcp for all MCP messages. GET /mcp from a browser returns the landing page, any other GET or HEAD returns 405 with Allow: POST (there is no server-to-client SSE stream in stateless mode).
No JSON-RPC batches (removed from the protocol in 2025-06-18). No CORS, so clients running directly inside a web page are not supported.
GET /mcp/health for monitoring.

Architecture

code

AI agent ──HTTPS──▶ nginx ──▶ doichain-mcp (this repo, 127.0.0.1:8081)
                                  │  REST calls only, client IP passed on for the quota
                                  ▼
                          Doichain REST API (127.0.0.1:8080) ──▶ Doichain Core v31.1.6 + ElectrumX

The MCP server is a thin, stateless layer over the Doichain REST API (interactive docs), which runs next to a full Doichain Core node. See docs/self-hosting.md to run your own instance.

Development

bash

python -m venv .venv
. .venv/bin/activate          # Windows: .venv\Scripts\activate
pip install -e ".[dev]"
pytest -q                     # offline tests, the REST API is mocked
ruff check .

# run locally against the public REST API (reading works, anchoring needs your own key)

[![Doichain Seal](https://doi-api.sendlabs.de/seal/github/neubuot/doichain-mcp/seal.svg)](https://doi-api.sendlabs.de/seal/github/neubuot/doichain-mcp)
DOI_MCP_API_URL=https://doi-api.sendlabs.de python -m doichain_mcp
npx @modelcontextprotocol/inspector   # connect to http://127.0.0.1:8081/mcp

Releases follow semantic versioning. Pushing a tag vX.Y.Z runs the tests and publishes server.json to the official MCP Registry via GitHub Actions (OIDC, no secrets). The tag, server.json and pyproject.toml must carry the same version. See CONTRIBUTING.md and CHANGELOG.md.

Verifile: proof of existence by drag and drop, no upload
Doichain REST API: the HTTP interface behind this server, with a live playground
Doichain Core: the reference node
Doichain Explorer: blocks, transactions and names

License and operator

Install

Tools (13)

get_chain_statushash_textcheck_proofanchor_proofget_anchoring_quotalookup_nameget_name_historycheck_name_expiry

Remote endpoint

Streamable HTTP

Hosted server - connect over the network, no local install.

url

https://doi-api.sendlabs.de/mcp

Add to VS Code Add to Cursor

claude_desktop_config.json

json

{
  "mcpServers": {
    "doichain": {
      "command": "npx",
      "args": [
        "-y",
        "mcp-remote",
        "https://doi-api.sendlabs.de/mcp"
      ]
    }
  }
}

Desktop config is stdio-only; this bridges via mcp-remote. Native remote: Settings > Connectors.

MCP Server: io.github.neubuot/doichain

🛠️ Key Features

🚀 Use Cases

⚡ Developer Benefits

⚠️ Limitations

Topics

get_chain_status

hash_text

check_proof

anchor_proof

get_anchoring_quota

lookup_name

get_name_history

check_name_expiry

search_names

get_block

get_transaction

get_address

verify_message

Doichain MCP Server

Quick start

Claude Code

Claude (web and desktop)

ChatGPT

Cursor

VS Code (Copilot agent mode)

Any other client

Tools

How a proof of existence works

Limits and quotas

Security and privacy

Protocol behavior

Architecture

Development

Related

License and operator

Install

Remote endpoint

Related servers