KG-NINJA MCP API

openapi: 3.2.0
info:
  title: Agent Verification Utility MCP API
  version: 0.4.3
  description: A deterministic, x402-paid JSON evidence verification service for external agents. The service attests that declared checks were executed; it does not attest real-world truth.
  license:
    name: UNLICENSED
servers:
- url: /
  description: Relative to the current deployment origin
security: []
tags:
- name: MCP
  description: Stateless MCP Streamable HTTP transport
paths:
  /server.json:
    get:
      operationId: getMcpRegistryServer
      summary: Get the official MCP Registry publication document
      description: Remote-server metadata using the official MCP Registry server.json schema. The publication namespace is derived from the configured public domain.
      tags:
      - MCP
      responses:
        '200':
          description: MCP Registry remote server document
          content:
            application/json:
              schema:
                type: object
  /mcp/server.json:
    get:
      operationId: getMcpRegistryServerAlias
      summary: Get the MCP Registry publication document beside the MCP endpoint
      tags:
      - MCP
      responses:
        '200':
          description: The same MCP Registry document as /server.json
          content:
            application/json:
              schema:
                type: object
  /.well-known/mcp-registry-auth:
    get:
      operationId: getMcpRegistryHttpProof
      summary: Get the optional MCP Registry HTTP domain-ownership proof
      description: Returns 404 until an operator generates a registry key and deploys its public proof. Private key material is never served.
      tags:
      - MCP
      responses:
        '200':
          description: MCP Registry public proof record
          content:
            text/plain:
              schema:
                type: string
        '404':
          description: Registry proof is not configured
  /docs/mcp-x402-interoperability:
    get:
      operationId: getMcpX402InteroperabilityGuide
      summary: Read the MCP and x402 interoperability guide
      tags:
      - MCP
      responses:
        '200':
          $ref: '#/components/responses/KnowledgeDocument'
  /webmcp.js:
    get:
      operationId: getWebMcpBridge
      summary: Get the feature-detected browser WebMCP bridge
      tags:
      - MCP
      responses:
        '200':
          description: Same-origin JavaScript bridge from WebMCP to the live MCP endpoint
          content:
            text/javascript:
              schema:
                type: string
  /mcp/server-card:
    get:
      operationId: getCurrentMcpServerCard
      summary: Get the current experimental MCP Server Card
      description: Publishes the experimental MCP Server Card v1 document next to the Streamable HTTP endpoint. Tool inventory remains authoritative at runtime through tools/list.
      tags:
      - MCP
      responses:
        '200':
          description: Experimental MCP Server Card
          headers:
            ETag:
              schema:
                type: string
              description: Strong SHA-256 entity tag; If-None-Match is supported.
          content:
            application/mcp-server-card+json:
              schema:
                type: object
                required:
                - $schema
                - name
                - description
                - version
                - remotes
                properties:
                  $schema:
                    type: string
                    const: https://static.modelcontextprotocol.io/schemas/v1/server-card.schema.json
                  name:
                    type: string
                    const: dev.kgninja/agent-verification-utility
                  title:
                    type: string
                  description:
                    type: string
                    maxLength: 100
                  version:
                    type: string
                  websiteUrl:
                    type: string
                    format: uri
                  icons:
                    type: array
                    items:
                      type: object
                      additionalProperties: true
                  remotes:
                    type: array
                    minItems: 1
                    items:
                      type: object
                      additionalProperties: true
                  _meta:
                    type: object
                    additionalProperties: true
                additionalProperties: true
        '304':
          description: Not modified
  /mcp:
    post:
      operationId: mcpStreamableHttp
      summary: Stateless MCP SDK v2 Streamable HTTP endpoint
      description: Exposes free discovery, revenue-goal, and quote tools plus the paid verify_evidence tool. The paid MCP tool uses x402 metadata and shares the audited POST /verify-evidence settlement and D1 ledger path.
      tags:
      - MCP
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              additionalProperties: true
      responses:
        '200':
          description: MCP protocol response
          content:
            application/json:
              schema:
                type: object
                additionalProperties: true
            text/event-stream:
              schema:
                type: string
        '400':
          $ref: '#/components/responses/BadRequest'
        '429':
          $ref: '#/components/responses/RateLimited'
        '503':
          $ref: '#/components/responses/Unavailable'
components:
  responses:
    BadRequest:
      description: Malformed request
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ErrorResponse'
    RateLimited:
      description: Rate limit exceeded
      headers:
        Retry-After:
          schema:
            type: integer
            minimum: 1
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ErrorResponse'
    KnowledgeDocument:
      description: Technical documentation with HTML and agent-optimized Markdown representations
      headers:
        Vary:
          schema:
            type: string
            const: Accept
        ETag:
          schema:
            type: string
        X-Markdown-Tokens:
          description: Approximate token count on the Markdown representation
          schema:
            type: integer
            minimum: 1
      content:
        text/html:
          schema:
            type: string
        text/markdown:
          schema:
            type: string
    Unavailable:
      description: Kill switch, maintenance, budget exhaustion, facilitator outage, or unavailable cost basis
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ErrorResponse'
  schemas:
    PaidVerificationBinding:
      type: object
      description: The immutable spend binding. quoted/payment_required have no paid receipt or refusal; refused has a refusal reason and no paid receipt; delivered has a paid receipt and no refusal reason, including when deterministic verification outcome is fail.
      additionalProperties: false
      required:
      - schema_version
      - binding_digest
      - precheck_receipt_digest
      - request_hash
      - evidence_digest
      - policy_version
      - price_cap_atomic
      - quoted_amount_atomic
      - network
      - asset
      - pay_to
      - quote_id
      - expires_at
      - discovery_survived
      - state
      - paid_receipt_id
      - refusal_reason
      properties:
        schema_version:
          type: string
          const: agent-economy/paid-verification-binding/1.0
        binding_digest:
          $ref: '#/components/schemas/Sha256Digest'
        precheck_receipt_digest:
          $ref: '#/components/schemas/Sha256Digest'
        request_hash:
          $ref: '#/components/schemas/Sha256Digest'
        evidence_digest:
          $ref: '#/components/schemas/Sha256Digest'
        policy_version:
          type: string
          const: agent-economy/precheck-policy/2.0
        price_cap_atomic:
          type: string
          maxLength: 16
          pattern: ^[1-9][0-9]*$
        quoted_amount_atomic:
          type: string
          maxLength: 16
          pattern: ^[1-9][0-9]*$
        network:
          type: string
          enum:
          - eip155:84532
          - eip155:8453
        asset:
          type: string
          pattern: ^0x[a-fA-F0-9]{40}$
        pay_to:
          type: string
          pattern: ^0x[a-fA-F0-9]{40}$
        quote_id:
          type: string
          pattern: ^qte_[A-Za-z0-9_-]+$
        expires_at:
          type: string
          format: date-time
        discovery_survived:
          type: boolean
          const: true
        state:
          type: string
          enum:
          - quoted
          - payment_required
          - delivered
          - refused
        paid_receipt_id:
          oneOf:
          - type: string
            pattern: ^rcpt_[A-Za-z0-9_-]+$
          - type: 'null'
        refusal_reason:
          oneOf:
          - type: string
            pattern: ^[A-Z0-9_]+$
          - type: 'null'
      oneOf:
      - properties:
          state:
            enum:
            - quoted
            - payment_required
          paid_receipt_id:
            type: 'null'
          refusal_reason:
            type: 'null'
      - properties:
          state:
            const: delivered
          paid_receipt_id:
            type: string
            pattern: ^rcpt_[A-Za-z0-9_-]+$
          refusal_reason:
            type: 'null'
      - properties:
          state:
            const: refused
          paid_receipt_id:
            type: 'null'
          refusal_reason:
            type: string
            pattern: ^[A-Z0-9_]+$
    Sha256Digest:
      type: string
      pattern: ^sha256:[a-f0-9]{64}$
    ErrorResponse:
      type: object
      additionalProperties: false
      required:
      - error
      properties:
        error:
          type: object
          additionalProperties: false
          required:
          - code
          - message
          - request_id
          - retryable
          properties:
            code:
              type: string
              pattern: ^[A-Z0-9_]+$
            message:
              type: string
            request_id:
              type: string
            retryable:
              type: boolean
            details:
              type: object
              properties:
                paid_verification_binding:
                  $ref: '#/components/schemas/RefusedPaidVerificationBinding'
              additionalProperties: true
    RefusedPaidVerificationBinding:
      allOf:
      - $ref: '#/components/schemas/PaidVerificationBinding'
      - properties:
          state:
            const: refused
  securitySchemes:
    agentRegistration:
      type: http
      scheme: bearer
      bearerFormat: signed anonymous registration receipt
      description: Optional 15-minute service-local receipt used only to inspect its own registration claim. It grants no API access and does not authorize payment.