OpenAPI spec redactor

Shrink an OpenAPI 3.x or Swagger 2.x document for LLM context by stripping verbose meta-fields (examples, descriptions, summaries, tags, externalDocs, deprecated). Send POST /api/openapi-redact 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 spec, sizeBefore, sizeAfter and removed.

Categories are explicit; default is `["examples", "descriptions"]`. User-defined property names under `properties: { ... }` are protected - only the meta-field `example` keyword inside a property schema is removed, not a user property literally named "example". Returns the redacted spec plus `sizeBefore`/`sizeAfter` (JSON byte length) and per-category removal counts so callers can see how much context they saved. Pure CPU - deterministic, no network.

Category: Data conversion · Tags: openapi swagger redact shrink llm-context api · Also found as: openapi-spec-redactor openapi-redactor

TRY IN PLAYGROUND →

Parameters

Example request

curl -i -X POST https://agent402.tools/api/openapi-redact \
  -H "Content-Type: application/json" \
  -d '{"spec":{"openapi":"3.0.0","info":{"title":"Demo","version":"1.0.0","description":"An example API"},"paths":{"/users":{"get":{"summary":"List users","description":"Returns all users.","parameters":[{"name":"limit","in":"query","description":"Max results","schema":{"type":"integer","example":10}}],"responses":{"200":{"description":"ok"}}}}}},"strip":["examples","descriptions"]}'

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

Example response

{
  "spec": {
    "openapi": "3.0.0",
    "info": {
      "title": "Demo",
      "version": "1.0.0"
    },
    "paths": {
      "/users": {
        "get": {
          "summary": "List users",
          "parameters": [
            {
              "name": "limit",
              "in": "query",
              "schema": {
                "type": "integer"
              }
            }
          ],
          "responses": {
            "200": {}
          }
        }
      }
    }
  },
  "sizeBefore": 334,
  "sizeAfter": 209,
  "removed": {
    "examples": 1,
    "descriptions": 4
  }
}

From an MCP client

catalog.call {
  "slug": "openapi-redact",
  "params": {
    "spec": {
      "openapi": "3.0.0",
      "info": {
        "title": "Demo",
        "version": "1.0.0",
        "description": "An example API"
      },
      "paths": {
        "/users": {
          "get": {
            "summary": "List users",
            "description": "Returns all users.",
            "parameters": [
              {
                "name": "limit",
                "in": "query",
                "description": "Max results",
                "schema": {
                  "type": "integer",
                  "example": 10
                }
              }
            ],
            "responses": {
              "200": {
                "description": "ok"
              }
            }
          }
        }
      }
    },
    "strip": [
      "examples",
      "descriptions"
    ]
  }
}

On the hosted connector at https://agent402.tools/mcp, catalog.call runs openapi-redact 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-redact 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-redact", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "spec": {
      "openapi": "3.0.0",
      "info": {
        "title": "Demo",
        "version": "1.0.0",
        "description": "An example API"
      },
      "paths": {
        "/users": {
          "get": {
            "summary": "List users",
            "description": "Returns all users.",
            "parameters": [
              {
                "name": "limit",
                "in": "query",
                "description": "Max results",
                "schema": {
                  "type": "integer",
                  "example": 10
                }
              }
            ],
            "responses": {
              "200": {
                "description": "ok"
              }
            }
          }
        }
      }
    },
    "strip": [
      "examples",
      "descriptions"
    ]
  }),
});

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-redact")).json();
let n = 0;
while (lz(createHash("sha256").update(c.challenge + ":" + n).digest()) < c.difficulty) n++;
await fetch("https://agent402.tools/api/openapi-redact", { method: "POST", headers: { "X-Pow-Solution": c.token + ":" + n, "Content-Type": "application/json" }, body: JSON.stringify({"spec":{"openapi":"3.0.0","info":{"title":"Demo","version":"1.0.0","description":"An example API"},"paths":{"/users":{"get":{"summary":"List users","description":"Returns all users.","parameters":[{"name":"limit","in":"query","description":"Max results","schema":{"type":"integer","example":10}}],"responses":{"200":{"description":"ok"}}}}}},"strip":["examples","descriptions"]}) });

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