OpenAPI operation search

Search operations in an OpenAPI 3.x or Swagger 2.x spec against a free-text query. Send POST /api/openapi-search with the required fields spec and query and pay $0.001 per call over x402 or MPP, or call it free by solving a proof-of-work challenge. It returns a JSON object with total and results.

Tokenizes the query (lowercase, alphanumeric runs), scores each operation by which fields the tokens match - operationId +3, path +3, tags +2, summary +2, description +1 per matched token - and returns ranked results with a `matches` array naming the contributing fields. Sort: score descending, then path ascending for stability. Limit defaults to 10 (max 100). Pure CPU - deterministic, no network, no $ref dereferencing.

Category: Data conversion · Tags: openapi swagger search ranking api agent-readiness

TRY IN PLAYGROUND →

Parameters

Example request

curl -i -X POST https://agent402.tools/api/openapi-search \
  -H "Content-Type: application/json" \
  -d '{"spec":{"paths":{"/users/{id}/avatar":{"put":{"operationId":"uploadUserAvatar","summary":"Upload user avatar","tags":["users"],"responses":{"200":{}}}},"/users/{id}":{"get":{"operationId":"getUser","summary":"Get a user","tags":["users"],"responses":{"200":{}}}},"/posts":{"get":{"operationId":"listPosts","summary":"List posts","tags":["posts"],"responses":{"200":{}}}}}},"query":"user avatar"}'

Without payment this returns HTTP 402 Payment Required with the exact price for openapi-search; any x402 v2 or MPP client pays it and retries.

Example response

{
  "total": 2,
  "results": [
    {
      "method": "PUT",
      "path": "/users/{id}/avatar",
      "operationId": "uploadUserAvatar",
      "summary": "Upload user avatar",
      "tags": [
        "users"
      ],
      "score": 18,
      "matches": [
        "operationId",
        "path",
        "summary",
        "tags"
      ]
    },
    {
      "method": "GET",
      "path": "/users/{id}",
      "operationId": "getUser",
      "summary": "Get a user",
      "tags": [
        "users"
      ],
      "score": 10,
      "matches": [
        "operationId",
        "path",
        "summary",
        "tags"
      ]
    }
  ]
}

From an MCP client

catalog.call {
  "slug": "openapi-search",
  "params": {
    "spec": {
      "paths": {
        "/users/{id}/avatar": {
          "put": {
            "operationId": "uploadUserAvatar",
            "summary": "Upload user avatar",
            "tags": [
              "users"
            ],
            "responses": {
              "200": {}
            }
          }
        },
        "/users/{id}": {
          "get": {
            "operationId": "getUser",
            "summary": "Get a user",
            "tags": [
              "users"
            ],
            "responses": {
              "200": {}
            }
          }
        },
        "/posts": {
          "get": {
            "operationId": "listPosts",
            "summary": "List posts",
            "tags": [
              "posts"
            ],
            "responses": {
              "200": {}
            }
          }
        }
      }
    },
    "query": "user avatar"
  }
}

On the hosted connector at https://agent402.tools/mcp, catalog.call runs openapi-search free (rate-limited, no wallet). Local install: npx -y agent402-mcp.

Errors and behavior

• spec and query are required. An input the tool rejects returns an HTTP 4xx whose body carries error, tool, expected, required and example, so the caller can correct it.
• A paid call that ends in any status of 400 or above is not charged over x402, MPP or a prepaid credits key: settlement is cancelled when the tool fails. The exception is a Tempo push credential, a transfer the buyer sent before the call: it settles before the tool runs, so if the tool then fails the payment is recorded as a refund owed to the paying wallet.
• Free tier: no outbound network call leaves the server for this tool, so proof-of-work (16 leading zero bits of sha256) pays for it.
• A GET or HEAD to /api/openapi-search returns the same 402 quote, so the price can be read without a body.
• An Idempotency-Key header makes a retried paid call replay the first 200 instead of charging again (an answer larger than 1 MB is not replayed).

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";

const client = new x402Client();
client.setSpendControls?.(false); // keep your own spending ceiling in code
registerExactEvmScheme(client, { signer: privateKeyToAccount(KEY) });
const payFetch = wrapFetchWithPayment(fetch, client);

const res = await payFetch("https://agent402.tools/api/openapi-search", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "spec": {
      "paths": {
        "/users/{id}/avatar": {
          "put": {
            "operationId": "uploadUserAvatar",
            "summary": "Upload user avatar",
            "tags": [
              "users"
            ],
            "responses": {
              "200": {}
            }
          }
        },
        "/users/{id}": {
          "get": {
            "operationId": "getUser",
            "summary": "Get a user",
            "tags": [
              "users"
            ],
            "responses": {
              "200": {}
            }
          }
        },
        "/posts": {
          "get": {
            "operationId": "listPosts",
            "summary": "List posts",
            "tags": [
              "posts"
            ],
            "responses": {
              "200": {}
            }
          }
        }
      }
    },
    "query": "user avatar"
  }),
});

No wallet? Pay with compute

Fetch a challenge, solve the sha256 puzzle (16 leading zero bits, a fraction of a second of CPU), and resend with the X-Pow-Solution header:

import { createHash } from "node:crypto";
const lz = (b) => { let t = 0; for (const x of b) { if (!x) { t += 8; continue; } t += Math.clz32(x) - 24; break; } return t; };
const c = await (await fetch("https://agent402.tools/api/pow/challenge?slug=openapi-search")).json();
let n = 0;
while (lz(createHash("sha256").update(c.challenge + ":" + n).digest()) < c.difficulty) n++;
await fetch("https://agent402.tools/api/openapi-search", { method: "POST", headers: { "X-Pow-Solution": c.token + ":" + n, "Content-Type": "application/json" }, body: JSON.stringify({"spec":{"paths":{"/users/{id}/avatar":{"put":{"operationId":"uploadUserAvatar","summary":"Upload user avatar","tags":["users"],"responses":{"200":{}}}},"/users/{id}":{"get":{"operationId":"getUser","summary":"Get a user","tags":["users"],"responses":{"200":{}}}},"/posts":{"get":{"operationId":"listPosts","summary":"List posts","tags":["posts"],"responses":{"200":{}}}}}},"query":"user avatar"}) });

Related tools