Dispute and refund verdicts for AI-agent payments, as LangChain.js and LangGraph.js tools. When your agent pays for a call and the result looks wrong, it sends what was promised, what came back and what was paid, and gets a signed Predge verdict: delivered, not_delivered or inconclusive, with reason codes and a refund recommendation. Every verdict is ed25519-signed and checked against Predge's published key.

Also included: a free signed settlement-risk check for Polymarket markets (read live from UMA's Optimistic Oracle on Polygon) and x402-paid Polymarket data.

Get a free key

Free pilot key in a minute: https://predge.io/start (no card)

First call: a signed delivery verdict for a paid agent call.

export PREDGE_KEY=pdg_pilot_...   # from predge.io/start
curl -s https://api.predge.io/v1/verdicts \
  -H 'content-type: application/json' \
  -H "x-predge-key: $PREDGE_KEY" \
  -d '{"job":{"endpoint":"https://api.example.com/v1/report","expected_content_type":"application/json","required_fields":["rows"]},
       "delivery":{"status":200,"headers":{"content-type":"application/json"},"body":"{\"rows\":[1]}"},
       "payment":{"amount_usd":0.25,"payer":"0xBuyer","payee":"0xMerchant"}}'

The response carries verdict (delivered / not_delivered / inconclusive), reason_codes, an ed25519 attestation and a verify_url. Docs: predge.io/docs#verdicts.

No key? Pay per call over x402 instead: the same request without x-predge-key answers 402 with the price ($0.05), payable in USDC by any x402 client.

Install

npm install @predge/langchain @langchain/core zod

Usage

import { createReactAgent } from "@langchain/langgraph/prebuilt";
import { ChatOpenAI } from "@langchain/openai";
import { createPredgeTools } from "@predge/langchain";

const agent = createReactAgent({
  llm: new ChatOpenAI({ model: "gpt-5-mini" }),
  tools: createPredgeTools({ apiKey: process.env.PREDGE_KEY }), // free pilot key: https://predge.io/start
});

const result = await agent.invoke({
  messages: [
    {
      role: "user",
      content:
        "I paid $0.25 to https://api.example.com/v1/report for JSON with a `rows` field. " +
        'It answered 200 with body {"error":"timeout"}. Ask Predge for a verdict and tell me if I should get a refund.',
    },
  ],
});

Without apiKey the tools read PREDGE_KEY from the environment. Without any key, predge_request_verdict is only returned when an account is configured (x402, below); the free tools need nothing. The refund is a recommendation the merchant executes. Predge does not move money.

Each tool returns a JSON string.

Paid tools (x402, USDC on Base)

import { privateKeyToAccount } from "viem/accounts";

const tools = createPredgeTools({
  account: privateKeyToAccount(process.env.BUYER_PRIVATE_KEY as `0x${string}`),
  maxPaymentUsd: 0.05, // per-call cap; 0 disables paid tools
});

With an account and no key, predge_request_verdict pays per verdict ($0.05 when the paid call is under $1; $0.50 at $1 or more, which needs maxPaymentUsd: 0.5). Payments use x402 v2 (exact scheme, EIP-3009 USDC authorization on Base). The tool pays only USDC on the account's chain and never more than maxPaymentUsd per call.

Tools

Tool	Price	What it does
`predge_request_verdict`	free with a pilot key; else $0.05 (< $1) / $0.50 (>= $1)	Signed delivery verdict for a paid call: `delivered` / `not_delivered` / `inconclusive`, reason codes, per-check results, refund recommendation, `verify_url`
`predge_get_verdict`	free	Reads a stored verdict by id (`vrd_...`) and checks its signature
`predge_get_settlement_risk`	free	Signed settlement-risk record for a market: `risk_level` (`ok`, `watch`, `caution`, `resolved`), UMA state, disputes, signature check
`predge_verify_record`	free	Verifies a Predge signed record offline against the pinned key
`predge_get_settlement_estimate`	$0.02	Same record plus `settlement_estimate` for a disputed market. Failed requests are not charged
`predge_get_whale_trades`	$0.005	Latest Polymarket trades of $10,000+ notional, delayed 15 minutes