Farcaster cast replies

The reply thread under a Farcaster cast (by hash or URL): the root cast plus replies flattened with their depth (1-5 levels) and parent hash, in chronological, newest-first or algorithmic order. Send POST /api/fc-cast-replies with the required field identifier and pay $0.005 per call over x402 or MPP (there is no free tier). It returns a JSON object with source, fetchedAt, cached, rateLimit, cast and 5 more.

Compact cast shape. Use to read reactions to an announcement, summarize a discussion, or trace who replied to whom.

Category: Web & documents · Tags: farcaster social replies thread conversation

TRY IN PLAYGROUND →

Parameters

Example request

curl -i -X POST https://agent402.tools/api/fc-cast-replies \
  -H "Content-Type: application/json" \
  -d '{"identifier":"0x322c451ed6ff1674328c6164b92166b3d15f2b7d","depth":1,"limit":10}'

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

Example response

{
  "source": "neynar",
  "fetchedAt": "2026-08-22T13:19:12.000Z",
  "cached": false,
  "rateLimit": {
    "limit": 300,
    "remaining": 299,
    "resetAt": "2026-08-22T13:20:00.000Z"
  },
  "cast": {
    "hash": "0x322c451ed6ff1674328c6164b92166b3d15f2b7d",
    "author": {
      "fid": 3,
      "username": "dwr",
      "displayName": "Dan Romero",
      "followerCount": 630338
    },
    "text": "quick let's all open up fc app to cast about fc dead",
    "timestamp": "2026-08-20T00:58:40.000Z",
    "channel": null,
    "parentHash": null,
    "reactions": {
      "likes": 196,
      "recasts": 28
    },
    "replies": 50,
    "embeds": [],
    "url": "https://warpcast.com/dwr/0x322c451e"
  },
  "depth": 1,
  "sort": "chron",
  "count": 1,
  "replies": [
    {
      "depth": 1,
      "hash": "0xab5aca846db8af6fa3dc2d25dc66171cd040def4",
      "author": {
        "fid": 3117427,
        "username": "askew-ai",
        "displayName": "askew-ai",
        "followerCount": 12
      },
      "text": "Paid an x402 endpoint for the first time today.",
      "timestamp": "2026-08-22T12:49:27.000Z",
      "channel": null,
      "parentHash": "0x322c451ed6ff1674328c6164b92166b3d15f2b7d",
      "reactions": {
        "likes": 4,
        "recasts": 1
      },
      "replies": 2,
      "embeds": [
        "https://example.com/post"
      ],
      "url": "https://warpcast.com/askew-ai/0xab5aca84"
    }
  ],
  "nextCursor": null
}

From an MCP client

catalog.call {
  "slug": "fc-cast-replies",
  "params": {
    "identifier": "0x322c451ed6ff1674328c6164b92166b3d15f2b7d",
    "depth": 1,
    "limit": 10
  }
}

The hosted connector at https://agent402.tools/mcp needs a payment for fc-cast-replies; the stdio package pays it from a wallet or from AGENT402_CREDITS_KEY. Local install: npx -y agent402-mcp.

Errors and behavior

• identifier 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.
• Wallet-only: this tool reaches the network or stored state, so it has no proof-of-work tier. A prepaid card-credits key issued earlier (Authorization: Bearer a402_...) also pays it.
• A GET or HEAD to /api/fc-cast-replies 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/fc-cast-replies", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "identifier": "0x322c451ed6ff1674328c6164b92166b3d15f2b7d",
    "depth": 1,
    "limit": 10
  }),
});

Related tools