Skill: API contract drift check

Bundled execution of the API contract drift check workflow - The 'did this API contract change in a way that breaks our integration?' workflow. Diff two OpenAPI snapshots structurally, lint the new one for agent-readiness regressions, extract the endpoint surface for inventory comparison, validate a known-good payload against the new contract, and summarize security-relevant changes. Six tools, one go/no-go answer on whether the upstream API broke us. One x402 payment runs 6 underlying tools (openapi-diff, openapi-lint, openapi-extract, openapi-required-params, openapi-validate-payload, openapi-security-summary); partial-success per step.

TRY IN PLAYGROUND →

Input

Example output

{
  "pack": "schema-evolution",
  "args": {
    "oldSpec": "{\"openapi\":\"3.0.3\",\"info\":{\"title\":\"Orders API\",\"version\":\"1.0.0\"},\"paths\":{\"/v1/orders\":{\"post\":{\"operationId\":\"createOrder\",\"requestBody\":{\"required\":true,\"content\":{\"application/json\":{\"schema\":{\"type\":\"object\",\"required\":[\"customerId\"],\"properties\":{\"customerId\":{\"type\":\"string\"},\"currency\":{\"type\":\"string\"}}}}}},\"responses\":{\"201\":{\"description\":\"created\"}}}}}}",
    "newSpec": "{\"openapi\":\"3.0.3\",\"info\":{\"title\":\"Orders API\",\"version\":\"1.1.0\"},\"paths\":{\"/v1/orders\":{\"post\":{\"operationId\":\"createOrder\",\"requestBody\":{\"required\":true,\"content\":{\"application/json\":{\"schema\":{\"type\":\"object\",\"required\":[\"customerId\",\"currency\"],\"properties\":{\"customerId\":{\"type\":\"string\"},\"currency\":{\"type\":\"string\"}}}}}},\"responses\":{\"201\":{\"description\":\"created\"}}}}}}"
  },
  "steps": [
    {
      "slug": "openapi-diff",
      "ok": true,
      "result": {}
    },
    {
      "slug": "openapi-lint",
      "ok": true,
      "result": {}
    },
    {
      "slug": "openapi-extract",
      "ok": true,
      "result": {}
    },
    {
      "slug": "openapi-required-params",
      "ok": true,
      "result": {}
    },
    {
      "slug": "openapi-validate-payload",
      "ok": true,
      "result": {}
    },
    {
      "slug": "openapi-security-summary",
      "ok": true,
      "result": {}
    }
  ],
  "summary": "6/6 steps succeeded"
}

Try it - see the 402 challenge (free)

curl -i -X POST https://agent402.tools/api/skill/schema-evolution \
  -H "Content-Type: application/json" \
  -d '{"oldSpec":"{\"openapi\":\"3.0.3\",\"info\":{\"title\":\"Orders API\",\"version\":\"1.0.0\"},\"paths\":{\"/v1/orders\":{\"post\":{\"operationId\":\"createOrder\",\"requestBody\":{\"required\":true,\"content\":{\"application/json\":{\"schema\":{\"type\":\"object\",\"required\":[\"customerId\"],\"properties\":{\"customerId\":{\"type\":\"string\"},\"currency\":{\"type\":\"string\"}}}}}},\"responses\":{\"201\":{\"description\":\"created\"}}}}}}","newSpec":"{\"openapi\":\"3.0.3\",\"info\":{\"title\":\"Orders API\",\"version\":\"1.1.0\"},\"paths\":{\"/v1/orders\":{\"post\":{\"operationId\":\"createOrder\",\"requestBody\":{\"required\":true,\"content\":{\"application/json\":{\"schema\":{\"type\":\"object\",\"required\":[\"customerId\",\"currency\"],\"properties\":{\"customerId\":{\"type\":\"string\"},\"currency\":{\"type\":\"string\"}}}}}},\"responses\":{\"201\":{\"description\":\"created\"}}}}}}"}'

The response is HTTP 402 Payment Required with exact payment requirements. Any x402 v2 client pays automatically and retries:

Paid call (JavaScript agent)

import { wrapFetchWithPayment } from "@x402/fetch";
import { x402Client } from "@x402/core/client";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";
import { metaTitle, metaDescription } from "./seo-meta.js";

const client = new x402Client();
client.setSpendControls?.(false); // @x402/core 2.23+ refuses anything over $1 or off the pegged-asset list by default; keep your own ceiling in code instead
registerExactEvmScheme(client, { signer: privateKeyToAccount(KEY) });
const payFetch = wrapFetchWithPayment(fetch, client);

const res = await payFetch("https://agent402.tools/api/skill/schema-evolution", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "oldSpec": "{\"openapi\":\"3.0.3\",\"info\":{\"title\":\"Orders API\",\"version\":\"1.0.0\"},\"paths\":{\"/v1/orders\":{\"post\":{\"operationId\":\"createOrder\",\"requestBody\":{\"required\":true,\"content\":{\"application/json\":{\"schema\":{\"type\":\"object\",\"required\":[\"customerId\"],\"properties\":{\"customerId\":{\"type\":\"string\"},\"currency\":{\"type\":\"string\"}}}}}},\"responses\":{\"201\":{\"description\":\"created\"}}}}}}",
    "newSpec": "{\"openapi\":\"3.0.3\",\"info\":{\"title\":\"Orders API\",\"version\":\"1.1.0\"},\"paths\":{\"/v1/orders\":{\"post\":{\"operationId\":\"createOrder\",\"requestBody\":{\"required\":true,\"content\":{\"application/json\":{\"schema\":{\"type\":\"object\",\"required\":[\"customerId\",\"currency\"],\"properties\":{\"customerId\":{\"type\":\"string\"},\"currency\":{\"type\":\"string\"}}}}}},\"responses\":{\"201\":{\"description\":\"created\"}}}}}}"
  }),
});

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