AffixIO MCP (hosted)

Zero-knowledge proofs with post-quantum attestations for AI agents, without exposing personal data.

AffixIO is a hosted, remote MCP server. There is nothing to install or run locally: point your MCP client at the endpoint below and sign in with AffixIO Studio.


Endpoint	`https://www.affix-io.com/mcp/`
Transport	Streamable HTTP
Authentication	OAuth 2.1 with PKCE, dynamic client registration, sign in via AffixIO Studio
Scopes	`mcp:read`, `mcp:write`
Tools	102
Official MCP Registry	`com.affix-io/affixio`
Quickstart	https://www.affix-io.com/docs/quickstart/

Note: This repository contains listing material only (documentation, example client configuration, registry metadata and logo). AffixIO is a hosted service and its server source code is not published here or anywhere else.

What AffixIO does

Zero-knowledge proofs for AI agents. Prove a yes or no fact (for example "over 18", "road legal", "within spending limit") without handing the underlying personal data to the agent or the model.
ML-DSA-65 post-quantum attestations. Every decision comes back signed with ML-DSA-65 (FIPS 204). The public key is available for offline verification.
Single-use proof IDs. Proofs can be marked spent, so the same proof cannot be replayed.
Agent trust. Enrol an AI agent, verify its credential and check whether it may perform a specific action against a named resource before it acts.
Auditable receipts. Verification receipts are anchored in a Merkle audit tree with inclusion proofs.

Free proofs

AI agents: 150 free proofs
Humans: 100 free proofs
No card required

Connect

AffixIO uses OAuth. The first time your client connects it will open a browser window for you to sign in to AffixIO Studio and approve access. No API key needs to go in your config file.

Clients that support remote servers (Cursor, Windsurf, Raycast and most modern clients)

{
  "mcpServers": {
    "affixio": {
      "url": "https://www.affix-io.com/mcp/"
    }
  }
}

Cline

Add this to cline_mcp_settings.json (MCP Servers, Configure, Edit configuration):

{
  "mcpServers": {
    "affixio": {
      "type": "streamableHttp",
      "url": "https://www.affix-io.com/mcp/"
    }
  }
}

Step-by-step instructions for agents are in llms-install.md.

VS Code (GitHub Copilot)

.vscode/mcp.json:

{
  "servers": {
    "affixio": {
      "type": "http",
      "url": "https://www.affix-io.com/mcp/"
    }
  }
}

Claude Desktop

Add AffixIO as a custom connector with the URL https://www.affix-io.com/mcp/, or use the mcp-remote bridge below in claude_desktop_config.json.

Fallback for stdio-only clients (`mcp-remote`)

If your client only supports local stdio servers, use mcp-remote, which handles the OAuth sign-in for you:

{
  "mcpServers": {
    "affixio": {
      "command": "npx",
      "args": ["-y", "mcp-remote", "https://www.affix-io.com/mcp/"]
    }
  }
}

Ready-made files are in examples/.

Tools

The server currently exposes 102 tools. A selection, grouped by area:

Area	Example tools
Core verification	`affix_verify`, `affix_verify_policies`, `affix_verify_reason_codes`, `affix_verify_receipts`, `affix_aggregate_verify`, `affix_proof_ref_verify`
Zero-knowledge circuits	`affix_list_circuits`, `affix_witness_prepare`, `affix_circuit_prove`, `affix_circuit_verify`
Post-quantum attestation	`affix_attestation_public_key`
Single-use proofs	`affix_spent_status`, `affix_spent_revoke`
Agent trust	`affix_agent_trust_enrol`, `affix_agent_trust_verify`, `affix_agent_trust_authorise`, `affix_agent_trust_audit`, `affix_agent_trust_badge`
Delegation and gates	`affix_delegate_issue`, `affix_delegate_verify`, `affix_gate_verify`, `affix_gate_quorum_start`, `affix_gate_multifactor_start`
Merkle audit	`affix_merkle_root`, `affix_merkle_proof`, `affix_merkle_verify_proof`, `affix_merkle_audit`, `affix_merkle_audit_batch`
Tokens and carriers	`affix_token_issue`, `affix_token_verify`, `affix_list_carriers`
Document parsing	`affix_mrz_parse`, `affix_aamva_parse`
Agentic payments	`agentic_pay_catalogue`, `agentic_pay_reverify`, `agentic_pay_charge`
Privacy guard	`edge_reject_pii`, `edge_audit`
UK vehicles	`vehicle_lookup`, `vehicle_check_road_legal`, `vehicle_check_clean_air`, `vehicle_check_fleet`, `vehicle_prove_circuits`, `road_legal_check`, `clean_air_check`
Eligibility passes	`age_check`, `ticket_check`, `travel_check`, `rent_check`, `stay_check`, `finance_check`, `money_check`, `right_pass_check`, `clearance_check`, `alevel_check_offer`, `ballot_session`
Discovery	`tools_catalogue`, `tools_search`, `tools_detail`, `affix_health`

Ask your agent to call tools_catalogue or simply list the server's tools to see the full set.

Example prompts

"Use AffixIO to prove this user is over 18 without sharing their date of birth, and show me the attestation."
"Is vehicle registration AB12 CDE road legal right now? Return the signed proof."
"Enrol this agent with AffixIO agent trust and check it may run checkout against store:orders."
"Check whether proof ID xyz has already been spent."

Security and privacy

Authentication is OAuth 2.1 with PKCE. Tokens are issued per client and scoped to mcp:read and mcp:write.
Account, key, OAuth and webhook administration is not exposed through MCP.
A signature protects a payload; it does not by itself establish that a source is true. See the documentation for the evidence boundaries of each proof mode.

Contact

[email protected]

Licence

The documentation, example configuration and metadata in this repository are licensed under CC BY 4.0. The AffixIO service, its server software and the AffixIO name and logo are proprietary and are not covered by that licence.

AffixIO MCP (hosted)