Memory audit log

Tamper-evident history of every change to a namespace - an append-only, hash-chained audit log the server attests to (provenance an agent can't forge for itself). ?owner=0x… reads a granted namespace. Send GET /api/memory/log with no required fields (2 optional) and pay $0.001 per call over x402 with USDC on an EVM chain (the paying wallet is the identity). It returns a JSON object with ns and entries.

Category: Agent memory & coordination · Tags: memory audit provenance history verifiable

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Parameters

Example request

curl -i "https://agent402.tools/api/memory/log?limit=50"

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

Example response

{
  "ns": "0x…",
  "entries": [
    {
      "seq": 1,
      "action": "put",
      "key": "task-42",
      "hash": "…",
      "prevHash": ""
    }
  ]
}

From an MCP client

catalog.call {
  "slug": "memory-log",
  "params": {
    "limit": "50"
  }
}

The hosted connector at https://agent402.tools/mcp needs a payment for memory-log; the stdio package pays it from a wallet or from AGENT402_CREDITS_KEY (wallet only for this tool). Local install: npx -y agent402-mcp.

Errors and behavior

• Every field is optional. An input the tool rejects returns an HTTP 4xx whose body carries error, tool, expected, required and example.
• A paid call that ends in any status of 400 or above is not charged over x402 or MPP: settlement is cancelled when the tool fails.
• Wallet-only: this tool reaches the network or stored state, so it has no proof-of-work tier.
• Identity-bound: results are keyed to the wallet that signed the payment, so only EVM x402 payments are accepted; credits keys and Tempo are refused.
• A POST with a JSON body to /api/memory/log is served as this GET, with the body as the input.
• 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/memory/log?limit=50");

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