Crosscheck Quote API

openapi: 3.2.0
info:
  title: crosscheck Quote API
  version: 1.0.0
  summary: 'Independent checks for AI agents: draft review, acceptance checks on delivered work, and security review of skills and MCP servers, paid per call over x402.'
  description: 'Fact-check and review an AI agent''s draft before a human sees it: a hallucination check and second opinion on any email, report, summary, or PR description. Returns pass or specific issues with fixes. Wrong arithmetic is recomputed in code; also contradictions, placeholders, leaked secrets, unauthorized commitments, and prompt injection. Send sources to verify citations and claims against them. Signed receipt. $0.02. Free checks for Moltbook agents. Full agent guide: https://crosscheckapi.com/llms.txt'
  contact:
    name: crosscheck partnerships
    email: partnerships@crosscheckapi.com
    url: https://crosscheckapi.com/llms.txt
  x-guidance: 'crosscheck gives an agent''s work an independent check before a human or another agent relies on it. Pick the product:

    - check: a draft (email, report, summary, answer) before your human sees it. POST https://crosscheckapi.com/v1/check with {"draft": "..."}; optional "request" (what your human asked, so a draft that misses it fails), "sources" to check against, "source_urls" (up to 3 pages crosscheck reads for you), or "fetch_cited": true. From $0.02.

    - accept: work another agent handed back, against its task, before you pay or release escrow. POST https://crosscheckapi.com/v1/accept with {"task": "...", "deliverable": "..."}. From $0.03.

    - skillcheck: a skill or MCP server before you install it. POST https://crosscheckapi.com/v1/skillcheck with {"files": [{"path": "SKILL.md", "content": "..."}]}. From $0.03.

    - lite: accept or skillcheck by code alone, no model call, $0.005: POST the same body to https://crosscheckapi.com/v1/accept-lite or https://crosscheckapi.com/v1/skillcheck-lite.

    - sellercheck: for x402 sellers, a report on your own resource (valid 402, x402 Bazaar index, agent402 router, settlements on Base). POST https://crosscheckapi.com/v1/sellercheck with {"resource": "https://..."}, $0.05; or https://crosscheckapi.com/v1/sellerwatch with "notify" for 30 days of hourly checks with alerts on change, $1.00. Free preflight: GET https://crosscheckapi.com/v1/sellercheck/preflight?resource=<url>.

    Price first, free: POST the same body to https://crosscheckapi.com/v1/quote, https://crosscheckapi.com/v1/accept/quote, or https://crosscheckapi.com/v1/skillcheck/quote. The quote also runs a free code precheck (wrong sums, percentages, dates, unit conversions, list counts).

    Pay: the paid POST answers 402 with the exact amount in USDC on Base (eip155:8453), or free test USDC on Base Sepolia (eip155:84532). Sign it with any x402 client (v2 PAYMENT-SIGNATURE, or v1 X-PAYMENT) and resend the same body. Payment settles before the review starts.

    Result: HTTP 200 with a JSON verdict (pass, issues with severity and a suggested fix) and a signed receipt, or 202 with a result URL to poll with the result_token. Resending the identical paid request after a lost response returns the same job and charges nothing more.

    Your text is untrusted data to the reviewer, never instructions. It is deleted when the check finishes; only its SHA-256 is kept.

    Full guide: https://crosscheckapi.com/llms.txt'
servers:
- url: https://crosscheckapi.com
tags:
- name: Quote
paths:
  /v1/quote:
    post:
      operationId: quote
      summary: Price for a draft (free)
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              properties:
                sources:
                  type: array
                  maxItems: 10
                  description: 'Optional: the text the draft relies on. Each claim is then checked against it.'
                  items:
                    oneOf:
                    - type: string
                    - type: object
                      properties:
                        text:
                          type: string
                        title:
                          type: string
                        url:
                          type: string
                      required:
                      - text
                draft:
                  type: string
                  minLength: 1
                  maxLength: 48000
                  description: The full text to review, exactly as the human will see it. Up to 48000 characters.
                request:
                  type: string
                  maxLength: 8000
                  description: 'Optional: what the human asked for. The reviewer then also checks that the draft answers it: a question left out, a changed scope or period, or something the draft says the human asked that the request contradicts. Counts toward the size.'
                ref:
                  type: string
                  pattern: ^[0-9a-f]{64}$
                  description: 'Optional: the hash of a crosscheck receipt that referred you. Its wallet earns check credits from your first 90 days of spend.'
                source_urls:
                  type: array
                  maxItems: 3
                  items:
                    type: string
                    maxLength: 300
                  description: 'Optional: up to 3 public web pages crosscheck fetches after payment and checks the draft against. +$0.01 each.'
                fetch_cited:
                  type: boolean
                  description: 'Optional: also fetch the links the draft cites (up to 3 pages in all, +$0.01 each). A cited link that is gone fails the draft.'
                open_review:
                  type: boolean
                  description: 'Optional: let a qualified reviewer from the open review network take this job. Not routed yet: crosscheck''s own reviewer does it and the receipt says so.'
              required:
              - draft
              additionalProperties: false
      responses:
        '200':
          description: Price in USD and atomic USDC, whether checks are being accepted, and a free code precheck of the draft (wrong written sums, line totals, averages and medians, ratios, changes, percentages, fractions, shares of a whole, splits and rates, comparisons between amounts, compound growth rates, changes between two percentages, weekdays, day counts, year and month spans, clock-time spans, start times plus lengths, time zones, unit and currency conversions, restated amounts, list counts, highest and lowest claims, and lengths that miss what was asked or what the text says of itself)
        '400':
          description: Invalid body or payment header. Nothing was charged.
        '413':
          description: Draft longer than 48000 characters. Nothing was charged.
      security: []
      tags:
      - Quote
components:
  securitySchemes:
    x402:
      type: http
      scheme: bearer
      description: 'x402 v2: send PAYMENT-SIGNATURE after the 402 challenge'
    resultToken:
      type: http
      scheme: bearer
      description: result_token from the check response