MCPF Initialize Response - Expected Format

Request Format

curl -X POST http://localhost:8787/mcp \
  -H "Content-Type: application/json" \
  -H "Accept: application/json, text/event-stream" \
  -d '{
    "jsonrpc": "2.0",
    "method": "initialize",
    "params": {
      "protocolVersion": "2025-03-26",
      "capabilities": {},
      "clientInfo": {
        "name": "test-client",
        "version": "1.0"
      }
    },
    "id": 1
  }'

Response Format (SSE Stream)

The server returns Server-Sent Events (SSE) format:

event: message
data: {JSON_RESPONSE}

Complete JSON Response Structure

{
  "result": {
    "protocolVersion": "2025-03-26",
    "capabilities": {
      "tools": {
        "listChanged": true
      }
    },
    "serverInfo": {
      "name": "kisc-arch-kultura-valodu-mcp",
      "version": "0.2.0"
    },
    "_meta": {
      "identity": {
        "id": "did:web:llm.kis.gov.lv",
        "service": {
          "mcp": "https://llm.kis.gov.lv/mcp"
        },
        "keys": {
          "jwks_uri": "https://llm.kis.gov.lv/.well-known/jwks.json"
        }
      },
      "mcpf": {
        "version": "0.1",
        "spec": {
          "repository": "https://github.com/MCPTrustFramework/MCPF-specification"
        },
        "entrypoint": {
          "type": "manifest",
          "url": "https://llm.kis.gov.lv/.well-known/mcp/manifest.json"
        },
        "artifacts": {
          "trust_registry": "https://llm.kis.gov.lv/.well-known/mcp-trust-registry.json",
          "credential": "https://veritrust.vc/portal/mcp/credentials/aec9930b-9139-4b33-ac6f-ad3bd3d91da0.json"
        }
      },
      "trust": {
        "verifications": [
          {
            "verifier": "did:web:veritrust.vc",
            "type": [
              "VerifiableCredential",
              "MCPServerVerification"
            ],
            "credential": "https://veritrust.vc/portal/mcp/credentials/aec9930b-9139-4b33-ac6f-ad3bd3d91da0.json",
            "covers": "did:web:llm.kis.gov.lv",
            "proof_hint": {
              "verificationMethod": "did:web:veritrust.vc#key-1",
              "created": "2026-01-29T10:12:41Z"
            }
          }
        ]
      }
    }
  },
  "jsonrpc": "2.0",
  "id": 1
}

MCPF Layer 1: Session-Level Trust Metadata

The _meta field contains three key sections:

1. Identity

{
  "id": "did:web:llm.kis.gov.lv",
  "service": {
    "mcp": "https://llm.kis.gov.lv/mcp"
  },
  "keys": {
    "jwks_uri": "https://llm.kis.gov.lv/.well-known/jwks.json"
  }
}

Purpose: Establishes the server's decentralized identity (DID) and key material location.

2. MCPF Metadata

{
  "version": "0.1",
  "spec": {
    "repository": "https://github.com/MCPTrustFramework/MCPF-specification"
  },
  "entrypoint": {
    "type": "manifest",
    "url": "https://llm.kis.gov.lv/.well-known/mcp/manifest.json"
  },
  "artifacts": {
    "trust_registry": "https://llm.kis.gov.lv/.well-known/mcp-trust-registry.json",
    "credential": "https://veritrust.vc/portal/mcp/credentials/aec9930b-9139-4b33-ac6f-ad3bd3d91da0.json"
  }
}

Purpose: Links to MCPF specification and trust artifacts for agent discovery.

3. Trust Verifications

{
  "verifications": [
    {
      "verifier": "did:web:veritrust.vc",
      "type": ["VerifiableCredential", "MCPServerVerification"],
      "credential": "https://veritrust.vc/portal/mcp/credentials/aec9930b-9139-4b33-ac6f-ad3bd3d91da0.json",
      "covers": "did:web:llm.kis.gov.lv",
      "proof_hint": {
        "verificationMethod": "did:web:veritrust.vc#key-1",
        "created": "2026-01-29T10:12:41Z"
      }
    }
  ]
}

Purpose: Documents third-party verification by VeriTrust credential service.

Verification Steps

An MCPF-aware agent should:

Extract DID from _meta.identity.id
Resolve DID document at https://llm.kis.gov.lv/.well-known/did.json
Fetch verification credential from VeriTrust
Verify credential signature using VeriTrust's public key
Check credential subject matches server DID
Optionally fetch trust registry and manifest for additional context

Test with jq

Extract specific fields:

# Get the DID
curl ... | grep '^data:' | sed 's/^data: //' | jq -r '.result._meta.identity.id'
# Output: did:web:llm.kis.gov.lv

# Get MCPF version
curl ... | grep '^data:' | sed 's/^data: //' | jq -r '.result._meta.mcpf.version'
# Output: 0.1

# Get verifier DID
curl ... | grep '^data:' | sed 's/^data: //' | jq -r '.result._meta.trust.verifications[0].verifier'
# Output: did:web:veritrust.vc

# Get credential URL
curl ... | grep '^data:' | sed 's/^data: //' | jq -r '.result._meta.trust.verifications[0].credential'
# Output: https://veritrust.vc/portal/mcp/credentials/aec9930b-9139-4b33-ac6f-ad3bd3d91da0.json

Notes

The _meta field is in addition to standard MCP initialize response fields
Backward compatible: non-MCPF clients ignore _meta
Layer 1 (session-level) + Layer 2 (per-response attestations) = Dual-layer trust
Session ID returned in Mcp-Session-Id response header (not shown in JSON)

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