Blankas MCP

Blankas enables AI agents to create, sign, and verify cryptographically verifiable agreements. It allows agents to issue numbered blank forms, co-sign terms, and verify signatures using Ed25519 keys, ensuring both parties have identical proof of what was agreed without revealing private keys.

Endpoint and access

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Community listingStreamable HTTPNo sign-inEndpoint checked 2026-11-01Published by sirsinatoriai-png

MCP endpoint (Streamable HTTP)

https://pvl.app.n8n.cloud/mcp/blankas-mcp

Vendor documentation

What you can do with it

Issue a blank agreement form between two AI agents
Co-sign deal terms and exchange signatures
Verify the validity of a signed agreement document
Mark a deal hash with a signed timestamped receipt

Source and maintenance

Community listingRegistry 0.1.0

mcp-registry: io.github.sirsinatoriai-png/blankas@0.1.0 Project website

Protocol and capabilities

Server: Blankas_MCP 0.1.0
MCP protocol: 2025-06-18
Tools: 6 advertised
Resources: Not advertised
Resource templates: Not advertised
Prompts: Not advertised

Server-advertised capabilities

{
  "tools": {}
}

Server-provided instructions

Untrusted server output shown for inspection. It is not Koskamo guidance and is excluded from knowledge search.

Blankas issues numbered, issuer-signed blank forms for deals between two AI agents. Flow: 1) blankas_issue with both parties public keys; 2) both parties fill the same content (form agent-deal-v1, see blankas_spec) and each signs the deal hash with its own Ed25519 key on its own side; 3) blankas_verify the completed document. Optional: blankas_mark registers a timestamped mark that contains only the hash. To sign without writing code, run the local Blankas signer MCP server, which keeps keys on the agent's own machine: uvx --from git+https://github.com/sirsinatoriai-png/Blankas blankas-mcp. Blankas never holds money and never needs private keys.

Tools

6 advertised

blankas_marks

Advertised by the server during the last successful anonymous check.

Look up timestamped proofs (marks) of an agreement between AI agents by blank ID.

blankas_marks input schema

{
  "type": "object",
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "required": [
    "blank_id"
  ],
  "properties": {
    "blank_id": {
      "type": "string",
      "description": "Blank ID, for example BLK-000001-7afb11"
    }
  },
  "additionalProperties": true
}

blankas_mark

Advertised by the server during the last successful anonymous check.

Timestamp proof that both AI agents signed an agreement: registers only the deal hash, never the terms. Kept 72 hours.

blankas_mark input schema

{
  "type": "object",
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "required": [
    "blank",
    "deal_hash",
    "signatures"
  ],
  "properties": {
    "blank": {
      "description": "The issued blank object exactly as returned by blankas_issue"
    },
    "deal_hash": {
      "type": "string",
      "description": "Deal hash: 64-character lowercase hex SHA-256"
    },
    "signatures": {
      "description": "Object with Ed25519 signatures a and b over the deal hash, base64url"
    }
  },
  "additionalProperties": true
}

blankas_verify

Advertised by the server during the last successful anonymous check.

Verify a co-signed agreement between AI agents. The document parameter must be the complete JSON object {blank, content, deal_hash, signatures}, not text. Checks the issuer signature, the terms and both party signatures; use it as proof of agreement or dispute evidence. Free. To look up timestamped marks by blank ID, use blankas_marks instead.

blankas_verify input schema

{
  "type": "object",
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "required": [
    "document"
  ],
  "properties": {
    "document": {
      "description": "The complete JSON object {blank, content, deal_hash, signatures}, not text"
    }
  },
  "additionalProperties": true
}

blankas_issue

Advertised by the server during the last successful anonymous check.

Start a verifiable agreement between two AI agents: issues a numbered, issuer-signed blank form for a deal, contract, order or service terms. Both parties then sign the same terms with their own keys, so each holds proof of agreement. Uses one free blank. Never send private keys.

blankas_issue input schema

{
  "type": "object",
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "required": [
    "party_a",
    "party_b"
  ],
  "properties": {
    "party_a": {
      "description": "Public keys of party A: object with sign (Ed25519) and box (X25519), each 32 raw bytes as base64url without padding"
    },
    "party_b": {
      "description": "Public keys of party B in the same format as party_a, different from party A"
    }
  },
  "additionalProperties": true
}

blankas_spec

Advertised by the server during the last successful anonymous check.

How to make a verifiable, co-signed agreement (contract) between two AI agents with Blankas: form fields, canonical JSON, deal hash and Ed25519 signing rules.

blankas_spec input schema

{
  "type": "object",
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "properties": {},
  "additionalProperties": true
}

blankas_info

Advertised by the server during the last successful anonymous check.

Status of Blankas, a free service for verifiable agreements between AI agents: issuer public key, free blanks left, links to the spec and to the local signer. Call this first.

blankas_info input schema

{
  "type": "object",
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "properties": {},
  "additionalProperties": true
}

Prompts

Not advertised

No prompt definitions available.

Resources

Not advertised

No resource definitions available.

30-day availability

Aggregated from read-only remote checks; this is not a tool-execution or security guarantee.

Successful checks: 1 of 1 (100%)
Average latency: 1270 ms
95th percentile latency: 1270 ms

Maintenance history

Public check and source-refresh events. Editorial and ownership records remain private.

Nov 1, 2026, 8:40 AM UTC · probe · passed · 1270 ms · metadata changed · 6 tool(s)

Connect from your client

Each snippet registers the same endpoint; pick the client you use.

This server is operated by the named third party. Listing and endpoint checks are not an endorsement or a security audit. Review the operator's permissions, terms, and data handling before connecting. How listings are checked and corrected.

Claude Code

Run this once in a terminal. It registers the remote server. Use --scope project to write .mcp.json for the repo.

Claude Code configuration

claude mcp add --transport http blankas-mcp https://pvl.app.n8n.cloud/mcp/blankas-mcp

Codex

Run this once. Codex stores MCP servers in ~/.codex/config.toml (or .codex/config.toml in a trusted project).

Codex configuration

codex mcp add blankas-mcp --url https://pvl.app.n8n.cloud/mcp/blankas-mcp

Cursor

Merge this server into .cursor/mcp.json in your project, then enable blankas-mcp in your MCP settings.

Cursor configuration

{
  "mcpServers": {
    "blankas-mcp": {
      "url": "https://pvl.app.n8n.cloud/mcp/blankas-mcp"
    }
  }
}

Cline

Merge this into cline_mcp_settings.json (Cline → MCP Servers → Configure).

Cline configuration

{
  "mcpServers": {
    "blankas-mcp": {
      "type": "streamableHttp",
      "url": "https://pvl.app.n8n.cloud/mcp/blankas-mcp",
      "disabled": false
    }
  }
}

VS Code

Merge this server into .vscode/mcp.json. Use MCP: List Servers to start blankas-mcp and inspect its tools.

VS Code configuration

{
  "servers": {
    "blankas-mcp": {
      "type": "http",
      "url": "https://pvl.app.n8n.cloud/mcp/blankas-mcp"
    }
  }
}

Gemini CLI

Run this once. It writes .gemini/settings.json in the current project; pass --scope user for ~/.gemini/settings.json.

Gemini CLI configuration

gemini mcp add --transport http blankas-mcp https://pvl.app.n8n.cloud/mcp/blankas-mcp

Claude Desktop

Merge this into claude_desktop_config.json (macOS: ~/Library/Application Support/Claude/, Windows: %APPDATA%\Claude\), then restart Claude Desktop.

Claude Desktop configuration

{
  "mcpServers": {
    "blankas-mcp": {
      "url": "https://pvl.app.n8n.cloud/mcp/blankas-mcp"
    }
  }
}

Windsurf

Merge this into ~/.codeium/windsurf/mcp_config.json, then refresh MCP in Cascade. Windsurf remote servers use serverUrl, not url.

Windsurf configuration

{
  "mcpServers": {
    "blankas-mcp": {
      "serverUrl": "https://pvl.app.n8n.cloud/mcp/blankas-mcp"
    }
  }
}

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