OpenAPI endpoint extractor

Flatten an OpenAPI 3.x or Swagger 2.x spec into a structured list of callable endpoints - one row per operation with method, path, operationId, summary, tags, parameters (name / in / required / type), JSON-body flag, and documented response codes. Send POST /api/openapi-extract with the required field spec 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 endpoints and stats.

Includes per-method and per-tag counts so an agent can pick what to call next without parsing the full spec. Output is sorted by path then method for stable, agent-friendly grouping. Pure CPU - deterministic, no network, no $ref dereferencing.

Category: Data conversion · Tags: openapi swagger extract endpoints api agent-readiness · Also found as: openapi-endpoint-extractor openapi-endpoints

TRY IN PLAYGROUND →

Parameters

Example request

curl -i -X POST https://agent402.tools/api/openapi-extract \
  -H "Content-Type: application/json" \
  -d '{"spec":{"openapi":"3.0.0","paths":{"/users":{"get":{"operationId":"listUsers","summary":"List users","tags":["users"],"parameters":[{"name":"limit","in":"query","required":false,"schema":{"type":"integer"}}],"responses":{"200":{"description":"ok"},"400":{"description":"bad"}}}},"/users/{id}":{"delete":{"operationId":"deleteUser","summary":"Delete user","tags":["users"],"parameters":[{"name":"id","in":"path","required":true,"schema":{"type":"string"}}],"responses":{"204":{"description":"gone"}}}}}}}'

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

Example response

{
  "endpoints": [
    {
      "method": "GET",
      "path": "/users",
      "operationId": "listUsers",
      "summary": "List users",
      "tags": [
        "users"
      ],
      "params": [
        {
          "name": "limit",
          "in": "query",
          "required": false,
          "type": "integer"
        }
      ],
      "hasJsonBody": false,
      "responses": [
        "200",
        "400"
      ]
    },
    {
      "method": "DELETE",
      "path": "/users/{id}",
      "operationId": "deleteUser",
      "summary": "Delete user",
      "tags": [
        "users"
      ],
      "params": [
        {
          "name": "id",
          "in": "path",
          "required": true,
          "type": "string"
        }
      ],
      "hasJsonBody": false,
      "responses": [
        "204"
      ]
    }
  ],
  "stats": {
    "total": 2,
    "byMethod": {
      "DELETE": 1,
      "GET": 1
    },
    "byTag": {
      "users": 2
    }
  }
}

From an MCP client

catalog.call {
  "slug": "openapi-extract",
  "params": {
    "spec": {
      "openapi": "3.0.0",
      "paths": {
        "/users": {
          "get": {
            "operationId": "listUsers",
            "summary": "List users",
            "tags": [
              "users"
            ],
            "parameters": [
              {
                "name": "limit",
                "in": "query",
                "required": false,
                "schema": {
                  "type": "integer"
                }
              }
            ],
            "responses": {
              "200": {
                "description": "ok"
              },
              "400": {
                "description": "bad"
              }
            }
          }
        },
        "/users/{id}": {
          "delete": {
            "operationId": "deleteUser",
            "summary": "Delete user",
            "tags": [
              "users"
            ],
            "parameters": [
              {
                "name": "id",
                "in": "path",
                "required": true,
                "schema": {
                  "type": "string"
                }
              }
            ],
            "responses": {
              "204": {
                "description": "gone"
              }
            }
          }
        }
      }
    }
  }
}

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

Errors and behavior

• spec is 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-extract 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-extract", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "spec": {
      "openapi": "3.0.0",
      "paths": {
        "/users": {
          "get": {
            "operationId": "listUsers",
            "summary": "List users",
            "tags": [
              "users"
            ],
            "parameters": [
              {
                "name": "limit",
                "in": "query",
                "required": false,
                "schema": {
                  "type": "integer"
                }
              }
            ],
            "responses": {
              "200": {
                "description": "ok"
              },
              "400": {
                "description": "bad"
              }
            }
          }
        },
        "/users/{id}": {
          "delete": {
            "operationId": "deleteUser",
            "summary": "Delete user",
            "tags": [
              "users"
            ],
            "parameters": [
              {
                "name": "id",
                "in": "path",
                "required": true,
                "schema": {
                  "type": "string"
                }
              }
            ],
            "responses": {
              "204": {
                "description": "gone"
              }
            }
          }
        }
      }
    }
  }),
});

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-extract")).json();
let n = 0;
while (lz(createHash("sha256").update(c.challenge + ":" + n).digest()) < c.difficulty) n++;
await fetch("https://agent402.tools/api/openapi-extract", { method: "POST", headers: { "X-Pow-Solution": c.token + ":" + n, "Content-Type": "application/json" }, body: JSON.stringify({"spec":{"openapi":"3.0.0","paths":{"/users":{"get":{"operationId":"listUsers","summary":"List users","tags":["users"],"parameters":[{"name":"limit","in":"query","required":false,"schema":{"type":"integer"}}],"responses":{"200":{"description":"ok"},"400":{"description":"bad"}}}},"/users/{id}":{"delete":{"operationId":"deleteUser","summary":"Delete user","tags":["users"],"parameters":[{"name":"id","in":"path","required":true,"schema":{"type":"string"}}],"responses":{"204":{"description":"gone"}}}}}}}) });

Part of these workflows

OpenAPI endpoint extractor is one step in this skill pack, each sold as a single call:

• API contract drift check - 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.

Related tools