Legacy Credential

Compatibility credential model for Level 1 implementations integrating with existing identity systems

Legacy Compatibility Credential

To facilitate integration with existing identity systems, MCP-I provides a Legacy Compatibility Credential model for Level 1 implementations.

Structure

{
  "@context": [
    "https://www.w3.org/2018/credentials/v1",
    "https://mcp-i.org/credentials/v1"
  ],
  "id": "urn:uuid:1a2b3c4d-5e6f-7g8h-9i0j-1k2l3m4n5o6p",
  "type": ["VerifiableCredential", "LegacyDelegationCredential"],
  "issuer": "did:example:idp456",
  "issuanceDate": "2025-04-20T14:25:10Z",
  "expirationDate": "2025-05-20T23:59:59Z",
  "credentialSubject": {
    "id": "did:example:agent101112",
    "scope": ["read:profile", "read:email"],
    "legacyIdentifier": {
      "type": "OAuth2Subject",
      "value": "user123@example.com",
      "issuer": "https://auth.example.com"
    }
  },
  "mappings": {
    "oauth": {
      "clientId": "client123",
      "scopes": ["profile", "email.read"]
    }
  },
  "proof": {
    "type": "Ed25519Signature2020",
    "created": "2025-04-20T14:25:10Z",
    "verificationMethod": "did:example:idp456#key-1",
    "proofPurpose": "assertionMethod",
    "proofValue": "zWaF5d8w93jWm..."
  }
}

Key Features

  • Legacy Identifier: Maps to existing identity systems like OAuth, OIDC, or LDAP
  • Mappings: Explicit mappings between MCP-I scopes and legacy authorization models
  • Limited Lifetime: Typically shorter expiration to manage security risk