MCP Verification Gate

{
  "name": "MCP Verification Gate",
  "description": "Checks whether an MCP server exists, publishes an agent card, discloses who pays it, and returns identical output for identical input. Free. Conformance and disclosure only; this gate does not verify that any price returned by a checked server is correct.",
  "url": "https://gate.horizonshield.dev/a2a",
  "version": "0.4.20",
  "capabilities": {
    "streaming": false,
    "pushNotifications": false,
    "extensions": [
      {
        "uri": "https://gate.horizonshield.dev/ext/conduct/v1",
        "description": "Who pays this agent, where its measured conduct record lives, and where to file a witness walk. The specification is served at the URI.",
        "required": false,
        "params": {
          "compensation": {
            "paid_by": "buyer",
            "referral_fee": false,
            "listing_fee": false,
            "success_fee_pct": 0,
            "disclosure_url": "https://shield.the-horizons-innovation.com/yakumo/plans/"
          },
          "measured_endpoints": [
            "https://gate.horizonshield.dev/mcp"
          ],
          "conduct_record": "https://gate.horizonshield.dev/history?endpoint=https%3A%2F%2Fgate.horizonshield.dev%2Fmcp",
          "verdict_recipe": "https://gate.horizonshield.dev/spec",
          "witness_intake": "https://ledger.horizonshield.dev/witness",
          "register": "https://gate.horizonshield.dev/register",
          "identity": {
            "kind": "did",
            "ref": "did:web:gate.horizonshield.dev"
          },
          "witness_policy": {
            "reciprocal": true
          },
          "witness_reply": {
            "transport": "a2a",
            "answers": "https://gate.horizonshield.dev/a2a",
            "request_schema": "nenrin-witness-request-v1",
            "reply_schema": "nenrin-witness-observation-v1",
            "key_url": "https://gate.horizonshield.dev/keys/witness.json",
            "surfaces": [
              "health.gate_commit",
              "agent-card.signature",
              "well-known.jwks",
              "well-known.openai-apps-challenge",
              "ext.conduct-v1.spec",
              "keys.agreement",
              "keys.witness",
              "keys.operator",
              "well-known.did"
            ],
            "note": "When drawn, this gate measures the listed public surfaces of the requested endpoint from its own vantage and returns one Ed25519-signed nenrin-witness-observation-v1 (the key served at key_url, conduct-v1.1 section 11.4). It refuses to witness itself (self_witness) and refuses non-public targets. reciprocal here means it answers a draw; it does not initiate an unprompted caller_card walk-back."
          },
          "rings": {
            "spec": "https://github.com/ogasurfproject-jpg/horizon-shield/blob/main/workers/hs-ledger/nenrin/NENRIN_SPEC_v1.md",
            "spec_sha256": "9ccba2e325fd2a555fcdb2dec519b8c6bf7a669064674846aea98ecfff824e3d",
            "base": "https://raw.githubusercontent.com/ogasurfproject-jpg/mcp-conduct-register/main/rings/",
            "path": "<slug>/<YYYY-MM>.json",
            "slug": "endpoint URL without https://, lower case, every run of characters outside [a-z0-9] replaced by one hyphen, hyphens trimmed at both ends",
            "ledger": "https://ledger.horizonshield.dev/ledger"
          }
        }
      },
      {
        "uri": "https://gate.horizonshield.dev/ext/legal-entity/v1",
        "description": "The legal entity that answers for this agent, declared inside the signed bytes. The specification is served at the URI.",
        "required": false,
        "params": {
          "registry": "JP",
          "scheme": "houjin-bango",
          "id": "7021001075279",
          "name": "The HORIZ音s Co., Ltd.",
          "lookup_url": "https://www.houjin-bangou.nta.go.jp/henkorireki-johoto.html?selHouzinNo=7021001075279"
        }
      }
    ]
  },
  "authentication": {
    "schemes": [
      "operator"
    ]
  },
  "defaultInputModes": [
    "text/plain"
  ],
  "defaultOutputModes": [
    "application/json",
    "text/plain"
  ],
  "skills": [
    {
      "id": "check",
      "name": "Conformance check",
      "description": "POST /check with an MCP endpoint URL, or call the check_conformance tool over MCP at /mcp. Returns a verdict with a recomputable SHA-256. Over A2A (SendMessage at /a2a), a text part carrying an MCP endpoint URL returns this gate's current register reading for it (the same bytes as GET /is-verified): verified true only on a full pass, null otherwise, never false.",
      "inputModes": [
        "text/plain",
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ],
      "tags": [
        "mcp",
        "verification",
        "conformance",
        "disclosure"
      ],
      "examples": [
        "Check https://example.com/mcp for conformance",
        "Does this server exist, publish an agent card, and return identical output for identical input?"
      ]
    },
    {
      "id": "verify",
      "name": "Verdict verification",
      "description": "Recompute the SHA-256 of a verdict this gate issued, so you do not have to trust the issuer. Available as the verify_verdict tool over MCP.",
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ],
      "tags": [
        "verification",
        "tamper-evident",
        "recomputable"
      ],
      "examples": [
        "Verify this verdict hashes to its own record_sha256",
        "Recompute the digest of a verdict returned by check"
      ]
    },
    {
      "id": "conditions",
      "name": "Verification conditions",
      "description": "Return the exact conditions this gate measures (MCP reachability, agent card, compensation disclosure, deterministic output) and how each verdict is recomputed. The get_conditions tool over MCP and GET /spec serve the same methodology.",
      "inputModes": [
        "text/plain"
      ],
      "outputModes": [
        "application/json"
      ],
      "tags": [
        "methodology",
        "transparency",
        "spec"
      ],
      "examples": [
        "What does this gate actually check?",
        "How is a verdict recomputed independently?"
      ]
    },
    {
      "id": "is-verified",
      "name": "Verification status",
      "description": "Report whether an endpoint's latest measurement passed all measured conditions. Returns true or null (state: verified, pending, held, watched, absent), never false. Available as the is_verified tool over MCP.",
      "inputModes": [
        "text/plain"
      ],
      "outputModes": [
        "application/json"
      ],
      "tags": [
        "verification",
        "status",
        "honest-null"
      ],
      "examples": [
        "Is https://example.com/mcp currently verified?",
        "What is this endpoint's latest state on the register?"
      ]
    },
    {
      "id": "lookup",
      "name": "Register lookup",
      "description": "Look up an endpoint's record on the public register: its latest verdict, state, and record SHA-256, with a recompute URL. Available as the lookup_server tool over MCP.",
      "inputModes": [
        "text/plain"
      ],
      "outputModes": [
        "application/json"
      ],
      "tags": [
        "register",
        "lookup",
        "recomputable"
      ],
      "examples": [
        "Look up the record for https://example.com/mcp",
        "Find the latest verdict hash for this endpoint"
      ]
    }
  ],
  "protocolVersion": "1.0",
  "preferredTransport": "JSONRPC"
}