@quackai/q402

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MCP server for Q402. Gasless USDC/USDT/RLUSD/Q payments on 12 EVM chains (USDG on Robinhood Chain), Q402 Yield (gasless supply and withdraw into Aave, Lista, and Morpho lending vaults), gasless non-cu

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1{2  "mcpServers": {3    "quackai-q402-mcp": {4      "command": "npx",5      "args": [6        "-y",7        "@quackai/[email protected]"8      ]9    }10  }11}

.cursor/mcp.jsonMCP server

Transport: stdio
Status: Local

Power your agent

Add this server

The publisher's own command. Not a PlugMCP endpoint.

Add to Cursor Add to VS Code Run on PlugMCP

Host a copy with our keys and logs.

Local command

npx -y @quackai/[email protected]

Claude Code has no install link for a local command. Copy the command below and run it in a terminal.

shClaude Code

1claude mcp add quackai-q402-mcp -- npx -y @quackai/q402-mcp@0.11.32

Run in a terminal.

jsonClaude Desktop

1{2  "mcpServers": {3    "quackai-q402-mcp": {4      "command": "npx",5      "args": [6        "-y",7        "@quackai/[email protected]"8      ]9    }10  }11}

claude_desktop_config.json

Local · npmPublisher installStep-by-step: add this in Claude

Remote URL or a command on your machine? How the two installs differ

Run on PlugMCP

Host a copy with our keys and logs.

A new server you create. It is not this listing's official endpoint. Use the publisher install when you want their URL and their credentials.

Launch

Server facts

Local

Transport: stdio
Version: 0.11.32
Last checked: 2026-10-28

Stars: —
Tools: —
Uptime: —

Overview

About @quackai/q402

Tools

No tool list yet. Remote servers get one after the first health check.

FAQ

Questions

How do I install @quackai/q402?

Copy the stdio config for Cursor, Claude Desktop, Claude Code, or VS Code on this page. It uses the publisher's install, not a PlugMCP proxy.

Does @quackai/q402 need an API key?

No required environment variable is listed on this record.

What transport does @quackai/q402 use?

@quackai/q402 runs locally over stdio.

When was @quackai/q402 last checked?

Last checked 2026-10-28. MCP server for Q402. Gasless USDC/USDT/RLUSD/Q payments on 12 EVM chains (USDG on Robinhood Chain), Q402 Yield (gasless supply and withdraw into Aave, Lista, and Morpho lending vaults), gasless non-custodial escrow (create, fund, release, refund, dispute)

From the publisher

Documentation

@quackai/q402-mcp

MCP server for Q402 - gasless USDC, USDT, RLUSD, and USDG payments across 12 EVM chains (USDG on Robinhood Chain), callable from Claude (Desktop / Code), OpenAI Codex CLI, and any other Model Context Protocol client.

Free trial available. 500 gasless transactions on BNB Chain + Base (USDC + USDT), no card. One wallet signature: https://q402.quackai.ai. Limited-time bonus: Mantle (USDC + USDT) is also covered by trial keys during 2026-08-21~08-28 UTC+9.

Trial-scope policy: API keys minted under the free-trial program (plan: "trial") settle on BNB Chain (USDC/USDT gasless) and Base (USDC/USDT gasless) as permanent chains. Avalanche trial has ended — use a Multichain key for avax. Mantle (USDC/USDT gasless) is covered during the limited-time window 2026-08-21~08-28 UTC+9 — server-side time enforcement, returns TRIAL_BNB_ONLY outside the window. Paid API keys see the full 12-chain matrix at all times.

Quote → route → (optional) settle stablecoin payments across 12 EVM chains, from any MCP client. Recipient gets the full amount; sender pays $0 gas via Q402's EIP-7702 relayer.

Quick start

Register the server with your client (one-line per client).
Say "Set up Q402" to your agent. It runs q402_doctor → creates ~/.q402/mcp.env → walks you through pasting keys.

1. Register the server

Client	Command / config
Claude Code (CLI)	`claude mcp add q402 -- npx -y @quackai/q402-mcp`
Claude Desktop (app)	Edit `claude_desktop_config.json` (Settings → Developer → Edit Config): `{ "mcpServers": { "q402": { "command": "npx", "args": ["-y", "@quackai/q402-mcp"] } } }`. Restart the app.
OpenAI Codex CLI	`codex mcp add q402 -- npx -y @quackai/q402-mcp` (Windows fallback: see below)
Cursor	Add to `~/.cursor/mcp.json`: `{ "mcpServers": { "q402": { "command": "npx", "args": ["-y", "@quackai/q402-mcp"] } } }`
Cline	Cline → Settings → MCP Servers → Edit JSON. Same shape as Cursor.
GitHub Copilot (VS Code)	Add to `.vscode/mcp.json` - root key is `servers`, not `mcpServers`: `{ "servers": { "q402": { "command": "npx", "args": ["-y", "@quackai/q402-mcp"] } } }`. Reload VS Code, then enable q402 in the Copilot Chat tools picker.
Hermes Agent (Nous Research)	YAML, not JSON. Add under `mcp_servers` in `~/.hermes/config.yaml` (see below), then run `/reload-mcp`.
Any other stdio MCP client	Point it at `npx -y @quackai/q402-mcp`. No client-specific code.

Hermes reads MCP servers from ~/.hermes/config.yaml under mcp_servers (YAML, not JSON):

mcp_servers:
  q402:
    command: "npx"
    args: ["-y", "@quackai/q402-mcp"]
    enabled: true

After editing, run /reload-mcp in Hermes to load the tools. Or use the CLI: hermes mcp add q402 --command npx --args -y @quackai/q402-mcp.

Claude Code (the CLI, claude binary) and Claude Desktop (the macOS / Windows app) are different products. The claude mcp add command only exists in the CLI; the Desktop app needs the JSON config above.

Secrets are NOT in this config. The server reads them from ~/.q402/mcp.env (same pattern as AWS / Stripe / gh CLIs).

Some Windows setups block codex.exe from writing its own config. Add the stanza to ~/.codex/config.toml by hand:

[mcp_servers.q402]
command = "npx"
args = ["-y", "@quackai/q402-mcp"]

Then restart Codex. Same effect as codex mcp add q402 -- npx -y @quackai/q402-mcp.

2. First-time setup

Restart your client, ask: > "Set up Q402"

The agent runs q402_doctor. On first install:

Creates ~/.q402/mcp.env (placeholders)
Opens it in your editor
Walks you through pasting an API key + a signing path into the file, not into chat
Restart + re-run q402_doctor to verify

Keys never paste into chat. Local modes sign on your machine; the key never leaves the device. Mode C (server-managed) needs no PK on the client.

Pick a signing mode

Mode	Env	Signer	Notes
A	`Q402_PRIVATE_KEY`	MetaMask EOA, local	Simplest. Shows "Smart account" after first use (reversible via `q402_clear_delegation`). After EIP-7702 delegation to an older implementation, `q402_x402_fetch` is unavailable until `q402_clear_delegation` is called (gasless, reversible; next `q402_pay` re-delegates). If delegated to the current ERC-1271-capable implementation, `q402_x402_fetch` works normally.
B	`Q402_AGENTIC_PRIVATE_KEY`	Agent Wallet, local	Export PK from the dashboard → Wallets → Danger Zone → Export private key. MetaMask untouched.
C	(just an API key)	Agent Wallet, server-managed	No PK on the client. One-shot pays accept Trial or Multichain keys; recurring needs Multichain on every chain (BNB included).

When more than one mode is set, q402_pay asks the user which to use. Picker: walletMode = "agentic-server" \| "agentic-local" \| "eoa".

Manual setup (no AI)

Create ~/.q402/mcp.env yourself with the template below. Live mode only flips when an API key + a signing path are populated, so saving the template as-is stays in sandbox. Q402_ENABLE_REAL_PAYMENTS=0 forces sandbox even with real keys.

# ~/.q402/mcp.env

# ── API key (pick one or both for auto-routing) ──
Q402_TRIAL_API_KEY=          # Free Trial, BNB (permanent) + Base (permanent) + Mantle limited-time (from /event)
Q402_MULTICHAIN_API_KEY=     # Paid Multichain, all 12 chains (from /payment)

# ── Signing path - pick ONE of Mode A / B / C ──
# Mode A: your MetaMask EOA's hex private key.
# Hardware wallets (Ledger / Trezor) are NOT supported here - Q402
# needs a raw hex key it can sign EIP-7702 type-4 authorizations with.
Q402_PRIVATE_KEY=

# Mode B: exported Agent Wallet pk from the dashboard. Keeps your
# MetaMask untouched. Get it at:
#   https://q402.quackai.ai/dashboard → Agent tab → Export
Q402_AGENTIC_PRIVATE_KEY=

# Mode C: no PK needed. A Trial key also enables Mode C one-shot payments;
# leave both PK lines blank. Q402 signs with the server-managed Agent Wallet.
# Multichain key required for recurring, Mode C batch, and bridge/OFT.
# Optional: pin one of your Agent Wallets when you have multiple (max 10).
# Q402_AGENT_WALLET_ADDRESS=0x...

# Live mode switch:
#   0 = sandbox (test mode, no funds move)
#   1 = real on-chain payments
# Default 1 - safe because mode only flips to live when an API key AND
# at least one valid signing path (A/B/C) are populated above.
Q402_ENABLE_REAL_PAYMENTS=1

# Default Q402 deployment. Only change for self-hosted.
Q402_RELAY_BASE_URL=https://q402.quackai.ai/api

# Safety guards (max-amount ships uncommented at $200; lower for tighter caps):
Q402_MAX_AMOUNT_PER_CALL=200
# Q402_ALLOWED_RECIPIENTS=0xabc...,0xdef...

# Pre-check (automatic trust-check before outgoing payments in live mode).
# Triggers when paying a first-time counterparty OR amount >= $1.
# Fee: $0.02 per check; verdict cached 7 days (no repeat charge within TTL).
# Set to 1 to disable pre-check entirely (even first-time / large-amount pays).
# Q402_DISABLE_PRECHECK=0

Then chmod 600 ~/.q402/mcp.env (Unix) and restart your client. That's the full configuration. Heads up on the EIP-7702 side effect: after your first live payment on a chain, your wallet will show 'Smart account' in MetaMask / OKX - that's the delegation Q402 uses for gasless settlement, reversible anytime via q402_clear_delegation. Important for x402 users: if EIP-7702 delegation is active on an older implementation, q402_x402_fetch cannot sign x402 payments until you call q402_clear_delegation (gasless on Base, reversible — the next q402_pay re-delegates automatically). Wallets delegated to the current ERC-1271-capable implementation work normally.

Advanced - explicit env injection

If you'd rather skip the file and inject env vars yourself (e.g. via Codex env_vars allow-list, a secrets manager, or shell exports), the server falls through to process.env - and process.env wins over file values on conflicts. So existing shell-export setups keep working unchanged.

[mcp_servers.q402]
command = "npx"
args = ["-y", "@quackai/q402-mcp"]
startup_timeout_sec = 20.0
env_vars = [
  "Q402_TRIAL_API_KEY",
  "Q402_MULTICHAIN_API_KEY",
  "Q402_PRIVATE_KEY",
  "Q402_AGENTIC_PRIVATE_KEY",
  "Q402_AGENT_WALLET_ADDRESS",
  "Q402_ENABLE_REAL_PAYMENTS",
  "Q402_RELAY_BASE_URL",
]

Then export the values in ~/.zshrc / ~/.bashrc. See the Codex config reference for the full schema.

Try it without any setup

q402_quote works with zero configuration - no API key, no private key, no env file. Ask:

"Compare gas costs to send 50 USDC to vitalik.eth across all 12 Q402 chains."

Q402_RELAY_BASE_URL overrides the relay endpoint. Set it explicitly when running against a self-hosted Q402 deployment or a non-canonical environment.

Tools exposed

49 tools, grouped by capability. Read-only by default; live mode needs a live API key, a signing path, and Q402_ENABLE_REAL_PAYMENTS=1. Rows marked live mode move funds and need an explicit in-chat confirmation.

Tool	Auth	Purpose
Payments & wallet
`q402_doctor`	none	First-install onboarding + ongoing health check (per-scope quota, EIP-7702 state, relay reachability, slot-mismatch warnings).
`q402_quote`	none	Compare gas + supported tokens across chains.
`q402_balance`	api key	Verify key + remaining quota.
`q402_pay`	live mode	Single-recipient gasless transfer. Sandbox by default. In live mode, automatically runs a trust-check ($0.02) on the recipient before each payment when it is a first-time counterparty or the amount ≥ $1; verdict cached 7 days (no double-charge within TTL). Degrades to free basic verdict only when wallet balance exactly covers the transfer but not the $0.02 fee, or when only a non-USDC rail token is available. Pre-check never blocks the main transaction. Disable with `Q402_DISABLE_PRECHECK=1`.
`q402_batch_pay`	live mode	Up to 20 recipients per call. Trial: 5 - applies when paying with your own key (Mode A/B); server-managed Agent Wallet (Mode C) batch is paid Multichain-only. Same auto-routing as `q402_pay`. 6+ BNB batches with Trial set return `status="ambiguous"` so the agent asks how to split. xlayer + stable not batchable - use `q402_pay` in a loop.
`q402_receipt`	none	Fetch + locally verify a Trust Receipt (`rct_…` id, ECDSA against the relayer EOA).
`q402_wallet_status`	private key	Per-chain EIP-7702 state for the EOA derived from `Q402_PRIVATE_KEY`.
`q402_clear_delegation`	private key / api key	Clear EIP-7702 delegation (Mode A/B local key OR Mode C api key, server-signed). Sponsored on every chain except Ethereum (billed to your Gas Tank). Two-phase consent (`consentToken`).
`q402_agentic_info`	api key	Agent Wallet info (addresses, per-wallet caps, daily-spend used, ERC-8004 id). Drives Mode C.
Treasury memory
`q402_memory_summary`	api key	Treasury overview over a window: USD-stablecoin spend by chain/source, top vendors, schedules, open requests/escrow, failures. Read-only.
`q402_vendor_history`	api key	Total paid to one vendor (or a vendor leaderboard) with recurring cadence. Read-only.
`q402_agent_spend_report`	api key	Per-Agent-Wallet spend with each wallet's caps. Read-only.
Recurring
`q402_recurring_list`	api key	List scheduled rules.
`q402_recurring_create`	api key	Author a recurring rule. Paid Multichain on EVERY chain (BNB included).
`q402_recurring_fires`	api key	Last 50 fires per rule (timestamp + txHashes + amount).
`q402_recurring_pause`	api key	Pause a rule (reversible).
`q402_recurring_resume`	api key	Resume a paused / stopped rule.
`q402_recurring_skip_next`	api key	Skip only the next scheduled fire.
`q402_recurring_cancel`	api key	Permanently stop a rule.
Bridge (CCIP + LayerZero)
`q402_bridge_quote`	none	Quote a Chainlink CCIP USDC bridge across eth/avax/arbitrum. Returns LINK + native fee.
`q402_bridge_send`	live mode	Execute a CCIP bridge from the user's Agent Wallet. Mode C only (server-managed). Sandbox-by-default; `sandbox: false` + live Multichain key + `Q402_ENABLE_REAL_PAYMENTS=1` fires a real on-chain bridge.
`q402_bridge_history`	not yet wired	Pointer to the dashboard. Returns `{ implemented: false, dashboardUrl, dashboardPath }` - read-only guidance until owner-sig auth lands in MCP.
`q402_bridge_gas_tank`	not yet wired	Static guidance + dashboard pointer for the Bridge Gas Tank top-up flow. Live balance lookup needs owner-sig auth (dashboard for now).
`q402_oft_quote`	none	Quote the LayerZero fee for bridging USDT0 across the OFT set (eth/arbitrum/mantle/monad/xlayer). Returns native messaging fee + delivered amount. Companion to `q402_bridge_quote` (CCIP/USDC).
`q402_oft_send`	live mode	Bridge USDT0 via LayerZero OFT from the Agent Wallet to the same address on the destination chain. Mode C (server-managed). Sandbox-by-default; `confirm: true` + live Multichain key + `Q402_ENABLE_REAL_PAYMENTS=1` fires a real bridge.
`q402_oft_history`	not yet wired	Pointer to the dashboard for LayerZero OFT bridge history. Returns `{ implemented: false, dashboardUrl }` - read-only guidance until owner-sig auth lands in MCP.
Yield
`q402_yield_reserves`	none	List Q402 Yield lending markets - protocol, chain, asset, market address, supply APY. Curated lending markets per chain (Aave/Lista on BNB, Morpho on Base); each market reports its own venue.
`q402_yield_positions`	api key	Show the Agent Wallet's open Q402 Yield positions (balance, principal, accrued interest, APY) + total supplied in USD. Mode C.
`q402_yield_deposit`	live mode	Supply the Agent Wallet's stablecoins into Q402 Yield's curated lending market per chain: BNB (USDC/USDT) or Base (USDC only). Mode C. Requires `confirm: true`; sandbox-by-default.
`q402_yield_withdraw`	live mode	Withdraw supplied stablecoins out of Q402 Yield (curated lending markets on BNB and Base) back to the Agent Wallet (`amount: "max"` = max currently redeemable, which vault caps or queues can leave below the full position). Mode C. Requires `confirm: true`; sandbox-by-default.
`q402_yield_cancel`	live mode	Cancel a pending Zircuit Finance withdraw request on Base. Zircuit withdrawals are queued (usually within 24 hours, up to 14 days); a canceled request returns the shares to the position. Mode C. Requires `confirm: true`; sandbox-by-default.
Staking
`q402_stake`	live mode	Gasless Q (QuackAI) staking into QuackAiStake on BNB Chain. Lock tiers 0-3 (30d/10%, 60d/15%, 120d/32%, 180d/40% APR). `amount: "max"` stakes the whole Q balance. Mode C. Requires `confirm: true`; sandbox-by-default.
`q402_unstake`	live mode	Gasless unstake of matured Q on BNB. Per-record: exit one stake by index (`ith`) or `all: true` for every matured stake. Mode C. Requires `confirm: true`; sandbox-by-default.
`q402_stake_positions`	live mode	The Agent Wallet's open Q stakes (indices, maturity, exitable) + liquid Q balance. Read-only; Mode C.
Payment requests
`q402_request_create`	api key	Publish a payment request (invoice). No funds move; returns a shareable `/pay` link + `req_…` id. Recipient defaults to the Agent Wallet.
`q402_request_status`	none	Look up a payment request by `req_…` id (amount, token, chain, recipient, status). Read-only; `notFound` instead of throwing.
`q402_request_pay`	live mode	Pay a request gaslessly from the payer's own Agent Wallet (Mode C). Terms come from the stored request, so they can't be redirected. Two-phase consent (same as `q402_pay`).
Escrow
`q402_escrow_create`	api key	Create a gasless non-custodial escrow (pending record, moves no funds); optional `walletId` funds it from an Agent Wallet. Chain availability served by GET /api/escrow/chains — the server enforces on every request.
`q402_escrow_status`	none	Read an escrow's state, parties, amount, and tx hashes. Read-only.
`q402_escrow_lock`	live mode	Fund a pending escrow gaslessly (EIP-7702); the server signs for an Agent-Wallet buyer. Sandbox-by-default. Chain availability served by GET /api/escrow/chains.
`q402_escrow_release`	live mode	Buyer releases a locked escrow to the seller (gasless). Sandbox-by-default.
`q402_escrow_refund`	live mode	Permissionless refund to the buyer after the timeout / resolve window.
`q402_escrow_dispute`	live mode	A party disputes an open escrow (requires a named arbiter).
Triggers (RedStone)
`q402_redstone_feeds`	none	Which RedStone feeds this deployment can drive triggers off (NAV / price / RWA). Read-only.
`q402_redstone_trigger_create`	live mode	Arm a gasless payout that fires once when a RedStone feed crosses a threshold (edge-latched).
`q402_redstone_trigger_list`	live mode	List the Agent Wallet's RedStone triggers + their state.
`q402_redstone_trigger_cancel`	live mode	Permanently stop a RedStone trigger.
x402 (outbound)
`q402_x402_fetch`	live mode	Fetch any x402-gated URL and handle HTTP 402 automatically: validates Base USDC payment option, guards against excess spend, signs EIP-3009 TransferWithAuthorization, and retries with the correct payment header (PAYMENT-SIGNATURE for v2 servers, X-PAYMENT for v1 legacy). Non-402 responses pass through unchanged. Returns `status:"settled_no_delivery"` (`fundsMoved:true, retrySafe:false`) when a txHash in the response confirms funds moved but the seller returned an error. Returns `status:"settled_status_unknown"` (`fundsMovedUnknown:true, retrySafe:false`) when no settlement proof exists — funds may or may not have moved. Do NOT retry either outcome.
`q402_governance_analyze`	live mode	Paid governance proposal analysis. Paste a snapshot.org / snapshot.box link (or raw text) and optionally describe your priority in plain language; get a vote recommendation (For / Against / Abstain), five dimension ratings, and the reasoning. Pass `language` (e.g. `"zh"`) to receive results in the user's language. $0.05 USDC per call on Base via x402.

q402_pay + q402_batch_pay + q402_bridge_send + q402_yield_deposit + q402_yield_withdraw + q402_yield_cancel + q402_stake + q402_unstake + q402_request_pay require explicit in-chat confirmation. Batch confirmation = full batch, not per-row.

Note: q402_pay expects a 0x address; ENS is not resolved server-side, so resolve it client-side first. Per-chain Gas Tank balances + full TX history live in the dashboard (wallet-signature only).

x402 outbound payments (q402_x402_fetch)

q402_x402_fetch is a general-purpose x402 client. It fetches any URL and handles HTTP 402 payment-required responses automatically. When the server returns a non-402 status, the response passes through unchanged, so it also works as a regular fetch tool.

What it solves. Some APIs and content endpoints use the x402 protocol to charge per-request. An agent hitting such a URL receives an HTTP 402 response with machine-readable payment requirements. q402_x402_fetch reads those requirements, validates the payment option, signs an EIP-3009 TransferWithAuthorization against Base USDC, encodes it as a base64 JSON payload, and retries the request — using PAYMENT-SIGNATURE for x402 v2 servers and X-PAYMENT for legacy v1 servers — all in one call.

Supported. scheme=exact + network=base (CAIP-2 eip155:8453; also accepted: base-mainnet) + Base USDC only. Any other scheme, network, or asset returns an explicit rejection and no signature is produced.

Guards (three layers).

Guard	Env var	Default
Per-call spend cap	`Q402_MAX_AMOUNT_PER_CALL`	$200
Per-session cumulative cap	`Q402_X402_SESSION_CAP_USD`	$5
Two-phase consent	`consentToken`	required on payment

Two-phase consent flow: the first call (without consentToken) returns needs_confirmation with a preview quoting the exact amount and recipient plus a consentToken. Present the quote to the user verbatim and wait for their next independent message confirming payment. Only then re-call with the same arguments plus the consentToken. The token is single-use, expires in ~120 seconds, and is rejected if consumed within 2 seconds of issuance (same-round double-call protection: a timing threshold, not a proof of human confirmation). Never re-call in the same conversation turn without a separate user confirmation message.

Result outcomes — read before summarizing to users.

Outcome	Fields	Meaning
`success: true`	`body`, `paid: true`, `payTo`, `amountUsd`	Content delivered, payment settled.
`success: false`, `needsConsent` set	`consentToken`, `preview`	No payment made. Re-call with `consentToken`.
`success: false`, `status: "settled_no_delivery"`	`fundsMoved: true`, `retrySafe: false`, `recipient`, `amount`, `txHash`, `guidance`	Funds confirmed left the wallet, content not delivered. Settlement is proven by `txHash` from the response. The seller accepted payment but returned an error. Do NOT tell the user "the payment didn't go through" — funds moved. Do NOT retry — that would make a second payment. Surface `amount`, `recipient`, `txHash`, and `guidance` to the user so they can reconcile with the seller.
`success: false`, `status: "settled_status_unknown"`	`fundsMovedUnknown: true`, `retrySafe: false`, `recipient`, `amount`, `txHash: null`, `guidance`	Settlement unknown — funds may or may not have moved. Payment header was sent but the response contained no settlement proof (no `txHash`). Do NOT assert that funds moved or didn't move. Do NOT retry with the same parameters — funds may have already moved. Surface `guidance` so the user can check their wallet balance and contact the seller.
`success: false` (other)	`error`	Payment blocked or rejected before settlement. No funds moved. Safe to retry.

Audit. Every 402 attempt — settled, settled_no_delivery, settled_status_unknown, or blocked — is written to the local audit log at ~/.q402/x402-audit.json and surfaced in q402_agent_spend_report. Both settled_no_delivery and settled_status_unknown outcomes count as spend in the report.

Minimum working example.

{
  "url": "https://api.example.com/data",
  "method": "GET",
  "confirm": true
}

If the endpoint returns 402, the tool responds with needs_confirmation and a consentToken. Present the quote to the user verbatim and wait for their next independent message. Re-call with those same arguments plus the consentToken to authorize payment. The token is single-use and expires in ~120 seconds.

Requirements. Q402_ENABLE_REAL_PAYMENTS=1 plus a local signing key (Q402_AGENTIC_PRIVATE_KEY or Q402_PRIVATE_KEY). The signed authorization goes directly to the seller's facilitator endpoint; the Q402 relay is not involved in this path.

Prerequisite — delegation check. If you have previously called q402_pay on this wallet, it may be EIP-7702-delegated (shown as 'Smart account' in MetaMask / OKX). If delegated to an older implementation, q402_x402_fetch will fail. Wallets delegated to the current ERC-1271-capable implementation work normally. Recovery: call q402_clear_delegation (gasless on Base, reversible). After clearing, q402_x402_fetch works again. The next q402_pay re-delegates automatically.

Governance analysis (q402_governance_analyze)

q402_governance_analyze analyzes a Snapshot governance proposal and returns a vote recommendation, five dimension scores, and the reasoning. $0.05 USDC per call on Base via x402.

Input parameters.

Parameter	Required	Description
`url`	one of	Snapshot proposal URL (snapshot.org or snapshot.box) or bare 0x proposal ID.
`proposalText`	one of	Raw proposal body text.
`proposalId`	one of	Snapshot proposal ID (`dao` defaults to `"snapshot"` when omitted).
`weights`	optional	Priority weights (0-100 integer each): `riskControl`, `decentralization`, `sustainability`, `communityImpact`. Mutually exclusive with `persona`.
`persona`	optional	Named analysis persona. Mutually exclusive with `weights`.
`language`	optional	BCP-47 language code for result display. Set to the user's conversation language, e.g. `"zh"` for Chinese, `"en"` for English (default). The server uses this to localize response fields; Claude also applies the built-in translation table so results are presented fully in the user's language.
`confirm`	required	Must be `true`. Attests user approved the $0.05 USDC charge.
`consentToken`	optional	Two-phase consent. Omit on first call; present the quote to the user and wait for their next independent message, then re-call with the token. Single-use, expires in ~120s.

Language-aware results. When language: "zh" is set, the vote recommendation, dimension names, ratings, and reasoning text are all presented in Chinese, with no English enum values shown to the user.

Sandbox vs live mode

Sandbox default: q402_pay returns a fake txHash with success: false and sandbox: true. No funds, no quota.

Live = (a) live API key (q402_live_*), (b) a signing path (A / B / C), (c) Q402_ENABLE_REAL_PAYMENTS=1. The live flag defaults to 1 - gate only flips when both other conditions are met. Set to 0 to force sandbox even with real keys.

Template q402_doctor writes to ~/.q402/mcp.env:

# ── API key - fill ONE (or both for auto-routing) ──
# Auto-routing (same for q402_pay AND q402_batch_pay):
#   chain="bnb" or "base" + Q402_TRIAL_API_KEY set  → Trial (free sponsored)
#   anything else                                    → Multichain (paid 12-chain)
# Batch ambiguity: 6+ recipient BNB/Base batch with Trial set returns
#   status="ambiguous" instead of executing - agent asks user to pick.
# Override per call with keyScope: "auto" | "trial" | "multichain".
Q402_TRIAL_API_KEY=                # BNB + Base sponsored Trial key (from /event; Avalanche trial ended)
Q402_MULTICHAIN_API_KEY=           # paid 12-chain key (per-chain Gas Tank)

# ── Signing path - pick ONE of Mode A / B / C ──
Q402_PRIVATE_KEY=                  # Mode A: real EOA pk (0x + 64 hex)
Q402_AGENTIC_PRIVATE_KEY=          # Mode B: exported Agent Wallet pk (from dashboard)
# Mode C: leave both PK lines blank. A Trial key enables one-shot Mode C
# payments; Multichain key required for recurring, batch, and bridge/OFT.
# Q402 signs with the server-managed Agent Wallet. Optionally:
# Q402_AGENT_WALLET_ADDRESS=0x...   # pin one of your wallets when you have multiple

# Live mode switch:
#   0 = sandbox (test mode, no funds move - every q402_pay returns a fake hash)
#   1 = real on-chain payments (live mode)
# Default 1. Safe because the gate only flips to live when an API key AND
# at least one valid signing path (A/B/C) are populated. Empty values
# fail the gate, so partial setups stay in sandbox with a hint.
Q402_ENABLE_REAL_PAYMENTS=1

# Pre-check trust-check (live mode). Triggers for first-time counterparties or
# payments >= $1. Fee: $0.02 per check; cached 7 days. Never blocks the main tx.
# Set Q402_DISABLE_PRECHECK=1 to opt out.

Anything missing for the resolved scope → automatic sandbox fallback with a hint pointing at what to set.

Sandbox responses carry success: false, sandbox: true, mode: "sandbox", method: "sandbox", plus a setupHint explaining why - four signals so a downstream summary can't claim success.

Hard caps

Env var	Default	Effect
`Q402_MAX_AMOUNT_PER_CALL`	`200`	Reject USDC/USDT/RLUSD calls with `amount > N` USD. Q (QuackAI) is exempt by design (your own token); the recipient allowlist + confirmation still apply to it.
`Q402_X402_SESSION_CAP_USD`	`5`	Per-session cumulative spend cap for `q402_x402_fetch` (USD). Blocked if the session total would exceed this value. Resets on MCP server restart.
`Q402_ALLOWED_RECIPIENTS`	off	Comma-separated address allowlist.
`Q402_BUILDER_CODE`	off	Base Builder Code for `q402_x402_fetch` on-chain attribution (ERC-8021 via x402 v2 `extensions.builder-code`).
`Q402_DISABLE_PRECHECK`	off	Set to `1` to opt out of the automatic pre-check trust-check on outgoing payments.

Combined with the two-phase consentToken + live-mode env, a stablecoin payment needs: a preview the user approved in a separate message + amount ≤ cap + recipient allowed + all 3 live envs. The consent token is single-use and expires in ~120 seconds; consuming it within 2 seconds of issuance triggers the same-round double-call gate (threshold, not a guarantee of human confirmation). Q (QuackAI) is exempt from the cap (your own token); the preview, recipient allowlist, and live-mode env still apply to it.

Configuration reference

Env var	Required for	Notes
`Q402_TRIAL_API_KEY`	live-pay (BNB + Base + Mantle)	BNB Chain + Base sponsored Trial key (permanent). Avalanche trial has ended — use Multichain for avax. Also covers Mantle during the limited-time window 2026-08-21~08-28 UTC+9. Free at https://q402.quackai.ai/event. Auto-routed for trial-eligible chains in both `q402_pay` and `q402_batch_pay` (≤5 recipients) when set. 6+ recipient trial batches return `status="ambiguous"` so the agent can ask the user how to split.
`Q402_MULTICHAIN_API_KEY`	live-pay (12-chain)	Paid 12-chain key. Get one at https://q402.quackai.ai/payment. Auto-routed for chains outside BNB/Base (including avax since the Avalanche trial ended) and for BNB/Base when no Trial key is set. Cap: 20 recipients per batch. Mode C one-shot pays accept Trial or Multichain; Multichain required for recurring, Mode C batch, and bridge/OFT.
`Q402_PRIVATE_KEY`	Mode A	Hex private key of your MetaMask EOA. Signer for local Mode A. Never share. Never paste in chat.
`Q402_AGENTIC_PRIVATE_KEY`	Mode B	Exported Agent Wallet hex private key from the dashboard (Agent tab → Export). Signs locally, but the signer is your dedicated Agent Wallet - MetaMask is never touched. Never share. Never paste in chat.
`Q402_AGENT_WALLET_ADDRESS`	Mode C (optional)	When you have multiple server-managed Agent Wallets (max 10 per owner), set this to the lowercased 0x… address of the one Q402 should spend from. Omit to use the default wallet. Ignored in Modes A/B.
`Q402_ENABLE_REAL_PAYMENTS`	live-pay	Set to `1` to opt in. Any other value (or unset) → sandbox.
`Q402_MAX_AMOUNT_PER_CALL`	optional	USD-equivalent cap for USDC/USDT/RLUSD. Defaults to `200`. Lower for tighter agent blast-radius. Q (QuackAI) is exempt by design (your own token).
`Q402_X402_SESSION_CAP_USD`	optional	Per-session cumulative spend cap for `q402_x402_fetch` (USD). Defaults to `5`. Resets on MCP server restart.
`Q402_ALLOWED_RECIPIENTS`	optional	Comma-separated lowercase addresses. Defaults to no allowlist.
`Q402_BUILDER_CODE`	optional	Base Builder Code (1–32 lowercase letters/numbers/underscores, e.g. `bc_fu2v7kgf`). Set to your registered Builder Code to attach on-chain ERC-8021 attribution to every `q402_x402_fetch` payment via the x402 `extensions.builder-code` field.
`Q402_DISABLE_PRECHECK`	optional	Set to `1` to disable the automatic pre-check trust-check that runs before outgoing payments in live mode. When unset (default), pre-check runs automatically for first-time counterparties and payments ≥ $1. The pre-check fee is $0.02; verdicts are cached 7 days (no repeat charge within TTL). The pre-check never blocks the main transaction.
`Q402_RELAY_BASE_URL`	optional	Defaults to `https://q402.quackai.ai/api`. Override for self-hosted Q402.

If you set up Q402 before v0.5.0 you may have a single Q402_API_KEY env var. The server still resolves that silently - your existing integration won't break. New installs should use the two-key model above (Q402_TRIAL_API_KEY and/or Q402_MULTICHAIN_API_KEY); q402_doctor and the rest of the docs only guide users to those two. To migrate, rename your existing var to Q402_MULTICHAIN_API_KEY in ~/.q402/mcp.env and restart your MCP client.

Supported chains

Chain	Chain ID	Token(s)	Notes
BNB Chain	56	USDC, USDT
Ethereum	1	USDC, USDT, RLUSD	L1 - gas is volatile, quote is a snapshot. RLUSD (Ripple USD, NY DFS regulated, decimals 18) Ethereum-only.
Avalanche C-Chain	43114	USDC, USDT
X Layer	196	USDC, USDT
Stable	988	USDT0 (USDC and USDT both alias)	Gas paid in USDT0.
Mantle	5000	USDC, USDT0	LayerZero OFT USDT0 since 2025-11-27.
Injective EVM	1776	USDC, USDT	Native Circle USDC (CCTP) live since 2026-06 + canonical Tether (USDT0).
Monad	143	USDC, USDT0	Native Circle USDC (CCTP V2) + USDT0 (LayerZero OFT).
Scroll	534352	USDC, USDT	zkEVM L2 - EIP-7702 live since the Euclid Phase 2 upgrade (2025-04-22).
Arbitrum One	42161	USDC, USDT	Optimistic rollup - same EIP-7702 signing path as Ethereum. CCIP bridge endpoint (eth ⇄ avax ⇄ arbitrum).
Base	8453	USDC, USDT	OP Stack L2 - same EIP-7702 signing path as Ethereum. Native Circle USDC + bridged Tether USD.
Robinhood Chain	4663	USDG	Arbitrum Nitro L2 - USDG only (Paxos Global Dollar, 6 decimals). Circle USDC / Tether are not canonical here; gasless USDG payments.

Why this exists

AI agents are becoming the default interface for software, but the moment they need to move money the stack breaks: holding gas tokens, signing every transaction, managing wallets across many chains. None of that scales when the agent is supposed to act on its own.

Q402 is the payment layer for that gap. A single signing primitive (EIP-712 + EIP-7702) settles gasless stablecoin payments across 12 EVM chains, with an ECDSA-signed Trust Receipt for every transaction. The MCP package exposes that surface inside Claude, Codex, Cursor, and Cline - your agent can quote, send, batch, and audit payments from a natural-language prompt.

Single transfers and multi-recipient batches ship today. The next layer - recurring payouts, conditional execution, and policy-gated treasury automation - is the same primitive composed differently. We're building toward agents that operate real budgets, settle among themselves, and move value through workflows no human triggers manually.

Hooks - programmable payment policies

Q402 Hooks 1.0 is a policy engine that attaches rules to the payment lifecycle: OFAC compliance screening, spend caps + recipient allowlists, ERC-8004 reputation gating, Chainlink-oracle conditional settlement ("only when BTC ≥ $80k"), and automatic multi-payee splits - plus an approval-required soft block for large payments (returns 202 approval_required; the caller re-submits out of band, no stored hold in v1). Uniswap v4 brought programmable hooks to DEX liquidity; Q402 brings them to AI-agent payments.

Developer reference: docs/HOOKS.md - lifecycle, the Hook contract, every shipped hook with config + examples.

Escrow on Base: docs/ESCROW-VS-INSTANT.md - instant vs. escrowed payment decision guide for agents. docs/ESCROW-BASE-DEPLOY-RUNBOOK.md - engineering runbook for Base mainnet vault deploy (hands-only, not for agents).

Repository

Source code: https://github.com/quackai-org/q402-mcp Issues / requests: https://github.com/quackai-org/q402-mcp/issues

License

Apache-2.0 - see LICENSE.

@quackai/q402

GitHub Actions

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Add to Cursor Add to VS Code Run on PlugMCP

GitHub npm Website

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1{2  "mcpServers": {3    "quackai-q402-mcp": {4      "command": "npx",5      "args": [6        "-y",7        "@quackai/[email protected]"8      ]9    }10  }11}

.cursor/mcp.jsonMCP server

Transport: stdio
Status: Local

Power your agent

Add this server

The publisher's own command. Not a PlugMCP endpoint.

Add to Cursor Add to VS Code Run on PlugMCP

Host a copy with our keys and logs.

Local command

npx -y @quackai/[email protected]

Claude Code has no install link for a local command. Copy the command below and run it in a terminal.

shClaude Code

1claude mcp add quackai-q402-mcp -- npx -y @quackai/q402-mcp@0.11.32

Run in a terminal.

jsonClaude Desktop

1{2  "mcpServers": {3    "quackai-q402-mcp": {4      "command": "npx",5      "args": [6        "-y",7        "@quackai/[email protected]"8      ]9    }10  }11}

claude_desktop_config.json

Local · npmPublisher installStep-by-step: add this in Claude

Remote URL or a command on your machine? How the two installs differ

Run on PlugMCP

Host a copy with our keys and logs.

A new server you create. It is not this listing's official endpoint. Use the publisher install when you want their URL and their credentials.

Launch

Server facts

Local

Transport: stdio
Version: 0.11.32
Last checked: 2026-10-28

Stars: —
Tools: —
Uptime: —

Overview

About @quackai/q402

Tools

No tool list yet. Remote servers get one after the first health check.

FAQ

Questions

How do I install @quackai/q402?

Copy the stdio config for Cursor, Claude Desktop, Claude Code, or VS Code on this page. It uses the publisher's install, not a PlugMCP proxy.

Does @quackai/q402 need an API key?

No required environment variable is listed on this record.

What transport does @quackai/q402 use?

@quackai/q402 runs locally over stdio.

When was @quackai/q402 last checked?

From the publisher

Documentation

@quackai/q402-mcp

MCP server for Q402 - gasless USDC, USDT, RLUSD, and USDG payments across 12 EVM chains (USDG on Robinhood Chain), callable from Claude (Desktop / Code), OpenAI Codex CLI, and any other Model Context Protocol client.

Free trial available. 500 gasless transactions on BNB Chain + Base (USDC + USDT), no card. One wallet signature: https://q402.quackai.ai. Limited-time bonus: Mantle (USDC + USDT) is also covered by trial keys during 2026-08-21~08-28 UTC+9.

Trial-scope policy: API keys minted under the free-trial program (plan: "trial") settle on BNB Chain (USDC/USDT gasless) and Base (USDC/USDT gasless) as permanent chains. Avalanche trial has ended — use a Multichain key for avax. Mantle (USDC/USDT gasless) is covered during the limited-time window 2026-08-21~08-28 UTC+9 — server-side time enforcement, returns TRIAL_BNB_ONLY outside the window. Paid API keys see the full 12-chain matrix at all times.

Quote → route → (optional) settle stablecoin payments across 12 EVM chains, from any MCP client. Recipient gets the full amount; sender pays $0 gas via Q402's EIP-7702 relayer.

Quick start

Register the server with your client (one-line per client).
Say "Set up Q402" to your agent. It runs q402_doctor → creates ~/.q402/mcp.env → walks you through pasting keys.

1. Register the server

Client	Command / config
Claude Code (CLI)	`claude mcp add q402 -- npx -y @quackai/q402-mcp`
Claude Desktop (app)	Edit `claude_desktop_config.json` (Settings → Developer → Edit Config): `{ "mcpServers": { "q402": { "command": "npx", "args": ["-y", "@quackai/q402-mcp"] } } }`. Restart the app.
OpenAI Codex CLI	`codex mcp add q402 -- npx -y @quackai/q402-mcp` (Windows fallback: see below)
Cursor	Add to `~/.cursor/mcp.json`: `{ "mcpServers": { "q402": { "command": "npx", "args": ["-y", "@quackai/q402-mcp"] } } }`
Cline	Cline → Settings → MCP Servers → Edit JSON. Same shape as Cursor.
GitHub Copilot (VS Code)	Add to `.vscode/mcp.json` - root key is `servers`, not `mcpServers`: `{ "servers": { "q402": { "command": "npx", "args": ["-y", "@quackai/q402-mcp"] } } }`. Reload VS Code, then enable q402 in the Copilot Chat tools picker.
Hermes Agent (Nous Research)	YAML, not JSON. Add under `mcp_servers` in `~/.hermes/config.yaml` (see below), then run `/reload-mcp`.
Any other stdio MCP client	Point it at `npx -y @quackai/q402-mcp`. No client-specific code.

Hermes reads MCP servers from ~/.hermes/config.yaml under mcp_servers (YAML, not JSON):

mcp_servers:
  q402:
    command: "npx"
    args: ["-y", "@quackai/q402-mcp"]
    enabled: true

After editing, run /reload-mcp in Hermes to load the tools. Or use the CLI: hermes mcp add q402 --command npx --args -y @quackai/q402-mcp.

Claude Code (the CLI, claude binary) and Claude Desktop (the macOS / Windows app) are different products. The claude mcp add command only exists in the CLI; the Desktop app needs the JSON config above.

Secrets are NOT in this config. The server reads them from ~/.q402/mcp.env (same pattern as AWS / Stripe / gh CLIs).

Some Windows setups block codex.exe from writing its own config. Add the stanza to ~/.codex/config.toml by hand:

[mcp_servers.q402]
command = "npx"
args = ["-y", "@quackai/q402-mcp"]

Then restart Codex. Same effect as codex mcp add q402 -- npx -y @quackai/q402-mcp.

2. First-time setup

Restart your client, ask: > "Set up Q402"

The agent runs q402_doctor. On first install:

Creates ~/.q402/mcp.env (placeholders)
Opens it in your editor
Walks you through pasting an API key + a signing path into the file, not into chat
Restart + re-run q402_doctor to verify

Keys never paste into chat. Local modes sign on your machine; the key never leaves the device. Mode C (server-managed) needs no PK on the client.

Pick a signing mode

Mode	Env	Signer	Notes
A	`Q402_PRIVATE_KEY`	MetaMask EOA, local	Simplest. Shows "Smart account" after first use (reversible via `q402_clear_delegation`). After EIP-7702 delegation to an older implementation, `q402_x402_fetch` is unavailable until `q402_clear_delegation` is called (gasless, reversible; next `q402_pay` re-delegates). If delegated to the current ERC-1271-capable implementation, `q402_x402_fetch` works normally.
B	`Q402_AGENTIC_PRIVATE_KEY`	Agent Wallet, local	Export PK from the dashboard → Wallets → Danger Zone → Export private key. MetaMask untouched.
C	(just an API key)	Agent Wallet, server-managed	No PK on the client. One-shot pays accept Trial or Multichain keys; recurring needs Multichain on every chain (BNB included).

When more than one mode is set, q402_pay asks the user which to use. Picker: walletMode = "agentic-server" \| "agentic-local" \| "eoa".

Manual setup (no AI)

# ~/.q402/mcp.env

# ── API key (pick one or both for auto-routing) ──
Q402_TRIAL_API_KEY=          # Free Trial, BNB (permanent) + Base (permanent) + Mantle limited-time (from /event)
Q402_MULTICHAIN_API_KEY=     # Paid Multichain, all 12 chains (from /payment)

# ── Signing path - pick ONE of Mode A / B / C ──
# Mode A: your MetaMask EOA's hex private key.
# Hardware wallets (Ledger / Trezor) are NOT supported here - Q402
# needs a raw hex key it can sign EIP-7702 type-4 authorizations with.
Q402_PRIVATE_KEY=

# Mode B: exported Agent Wallet pk from the dashboard. Keeps your
# MetaMask untouched. Get it at:
#   https://q402.quackai.ai/dashboard → Agent tab → Export
Q402_AGENTIC_PRIVATE_KEY=

# Mode C: no PK needed. A Trial key also enables Mode C one-shot payments;
# leave both PK lines blank. Q402 signs with the server-managed Agent Wallet.
# Multichain key required for recurring, Mode C batch, and bridge/OFT.
# Optional: pin one of your Agent Wallets when you have multiple (max 10).
# Q402_AGENT_WALLET_ADDRESS=0x...

# Live mode switch:
#   0 = sandbox (test mode, no funds move)
#   1 = real on-chain payments
# Default 1 - safe because mode only flips to live when an API key AND
# at least one valid signing path (A/B/C) are populated above.
Q402_ENABLE_REAL_PAYMENTS=1

# Default Q402 deployment. Only change for self-hosted.
Q402_RELAY_BASE_URL=https://q402.quackai.ai/api

# Safety guards (max-amount ships uncommented at $200; lower for tighter caps):
Q402_MAX_AMOUNT_PER_CALL=200
# Q402_ALLOWED_RECIPIENTS=0xabc...,0xdef...

# Pre-check (automatic trust-check before outgoing payments in live mode).
# Triggers when paying a first-time counterparty OR amount >= $1.
# Fee: $0.02 per check; verdict cached 7 days (no repeat charge within TTL).
# Set to 1 to disable pre-check entirely (even first-time / large-amount pays).
# Q402_DISABLE_PRECHECK=0

Advanced - explicit env injection

[mcp_servers.q402]
command = "npx"
args = ["-y", "@quackai/q402-mcp"]
startup_timeout_sec = 20.0
env_vars = [
  "Q402_TRIAL_API_KEY",
  "Q402_MULTICHAIN_API_KEY",
  "Q402_PRIVATE_KEY",
  "Q402_AGENTIC_PRIVATE_KEY",
  "Q402_AGENT_WALLET_ADDRESS",
  "Q402_ENABLE_REAL_PAYMENTS",
  "Q402_RELAY_BASE_URL",
]

Then export the values in ~/.zshrc / ~/.bashrc. See the Codex config reference for the full schema.

Try it without any setup

q402_quote works with zero configuration - no API key, no private key, no env file. Ask:

"Compare gas costs to send 50 USDC to vitalik.eth across all 12 Q402 chains."

Q402_RELAY_BASE_URL overrides the relay endpoint. Set it explicitly when running against a self-hosted Q402 deployment or a non-canonical environment.

Tools exposed

Tool	Auth	Purpose
Payments & wallet
`q402_doctor`	none	First-install onboarding + ongoing health check (per-scope quota, EIP-7702 state, relay reachability, slot-mismatch warnings).
`q402_quote`	none	Compare gas + supported tokens across chains.
`q402_balance`	api key	Verify key + remaining quota.
`q402_pay`	live mode	Single-recipient gasless transfer. Sandbox by default. In live mode, automatically runs a trust-check ($0.02) on the recipient before each payment when it is a first-time counterparty or the amount ≥ $1; verdict cached 7 days (no double-charge within TTL). Degrades to free basic verdict only when wallet balance exactly covers the transfer but not the $0.02 fee, or when only a non-USDC rail token is available. Pre-check never blocks the main transaction. Disable with `Q402_DISABLE_PRECHECK=1`.
`q402_batch_pay`	live mode	Up to 20 recipients per call. Trial: 5 - applies when paying with your own key (Mode A/B); server-managed Agent Wallet (Mode C) batch is paid Multichain-only. Same auto-routing as `q402_pay`. 6+ BNB batches with Trial set return `status="ambiguous"` so the agent asks how to split. xlayer + stable not batchable - use `q402_pay` in a loop.
`q402_receipt`	none	Fetch + locally verify a Trust Receipt (`rct_…` id, ECDSA against the relayer EOA).
`q402_wallet_status`	private key	Per-chain EIP-7702 state for the EOA derived from `Q402_PRIVATE_KEY`.
`q402_clear_delegation`	private key / api key	Clear EIP-7702 delegation (Mode A/B local key OR Mode C api key, server-signed). Sponsored on every chain except Ethereum (billed to your Gas Tank). Two-phase consent (`consentToken`).
`q402_agentic_info`	api key	Agent Wallet info (addresses, per-wallet caps, daily-spend used, ERC-8004 id). Drives Mode C.
Treasury memory
`q402_memory_summary`	api key	Treasury overview over a window: USD-stablecoin spend by chain/source, top vendors, schedules, open requests/escrow, failures. Read-only.
`q402_vendor_history`	api key	Total paid to one vendor (or a vendor leaderboard) with recurring cadence. Read-only.
`q402_agent_spend_report`	api key	Per-Agent-Wallet spend with each wallet's caps. Read-only.
Recurring
`q402_recurring_list`	api key	List scheduled rules.
`q402_recurring_create`	api key	Author a recurring rule. Paid Multichain on EVERY chain (BNB included).
`q402_recurring_fires`	api key	Last 50 fires per rule (timestamp + txHashes + amount).
`q402_recurring_pause`	api key	Pause a rule (reversible).
`q402_recurring_resume`	api key	Resume a paused / stopped rule.
`q402_recurring_skip_next`	api key	Skip only the next scheduled fire.
`q402_recurring_cancel`	api key	Permanently stop a rule.
Bridge (CCIP + LayerZero)
`q402_bridge_quote`	none	Quote a Chainlink CCIP USDC bridge across eth/avax/arbitrum. Returns LINK + native fee.
`q402_bridge_send`	live mode	Execute a CCIP bridge from the user's Agent Wallet. Mode C only (server-managed). Sandbox-by-default; `sandbox: false` + live Multichain key + `Q402_ENABLE_REAL_PAYMENTS=1` fires a real on-chain bridge.
`q402_bridge_history`	not yet wired	Pointer to the dashboard. Returns `{ implemented: false, dashboardUrl, dashboardPath }` - read-only guidance until owner-sig auth lands in MCP.
`q402_bridge_gas_tank`	not yet wired	Static guidance + dashboard pointer for the Bridge Gas Tank top-up flow. Live balance lookup needs owner-sig auth (dashboard for now).
`q402_oft_quote`	none	Quote the LayerZero fee for bridging USDT0 across the OFT set (eth/arbitrum/mantle/monad/xlayer). Returns native messaging fee + delivered amount. Companion to `q402_bridge_quote` (CCIP/USDC).
`q402_oft_send`	live mode	Bridge USDT0 via LayerZero OFT from the Agent Wallet to the same address on the destination chain. Mode C (server-managed). Sandbox-by-default; `confirm: true` + live Multichain key + `Q402_ENABLE_REAL_PAYMENTS=1` fires a real bridge.
`q402_oft_history`	not yet wired	Pointer to the dashboard for LayerZero OFT bridge history. Returns `{ implemented: false, dashboardUrl }` - read-only guidance until owner-sig auth lands in MCP.
Yield
`q402_yield_reserves`	none	List Q402 Yield lending markets - protocol, chain, asset, market address, supply APY. Curated lending markets per chain (Aave/Lista on BNB, Morpho on Base); each market reports its own venue.
`q402_yield_positions`	api key	Show the Agent Wallet's open Q402 Yield positions (balance, principal, accrued interest, APY) + total supplied in USD. Mode C.
`q402_yield_deposit`	live mode	Supply the Agent Wallet's stablecoins into Q402 Yield's curated lending market per chain: BNB (USDC/USDT) or Base (USDC only). Mode C. Requires `confirm: true`; sandbox-by-default.
`q402_yield_withdraw`	live mode	Withdraw supplied stablecoins out of Q402 Yield (curated lending markets on BNB and Base) back to the Agent Wallet (`amount: "max"` = max currently redeemable, which vault caps or queues can leave below the full position). Mode C. Requires `confirm: true`; sandbox-by-default.
`q402_yield_cancel`	live mode	Cancel a pending Zircuit Finance withdraw request on Base. Zircuit withdrawals are queued (usually within 24 hours, up to 14 days); a canceled request returns the shares to the position. Mode C. Requires `confirm: true`; sandbox-by-default.
Staking
`q402_stake`	live mode	Gasless Q (QuackAI) staking into QuackAiStake on BNB Chain. Lock tiers 0-3 (30d/10%, 60d/15%, 120d/32%, 180d/40% APR). `amount: "max"` stakes the whole Q balance. Mode C. Requires `confirm: true`; sandbox-by-default.
`q402_unstake`	live mode	Gasless unstake of matured Q on BNB. Per-record: exit one stake by index (`ith`) or `all: true` for every matured stake. Mode C. Requires `confirm: true`; sandbox-by-default.
`q402_stake_positions`	live mode	The Agent Wallet's open Q stakes (indices, maturity, exitable) + liquid Q balance. Read-only; Mode C.
Payment requests
`q402_request_create`	api key	Publish a payment request (invoice). No funds move; returns a shareable `/pay` link + `req_…` id. Recipient defaults to the Agent Wallet.
`q402_request_status`	none	Look up a payment request by `req_…` id (amount, token, chain, recipient, status). Read-only; `notFound` instead of throwing.
`q402_request_pay`	live mode	Pay a request gaslessly from the payer's own Agent Wallet (Mode C). Terms come from the stored request, so they can't be redirected. Two-phase consent (same as `q402_pay`).
Escrow
`q402_escrow_create`	api key	Create a gasless non-custodial escrow (pending record, moves no funds); optional `walletId` funds it from an Agent Wallet. Chain availability served by GET /api/escrow/chains — the server enforces on every request.
`q402_escrow_status`	none	Read an escrow's state, parties, amount, and tx hashes. Read-only.
`q402_escrow_lock`	live mode	Fund a pending escrow gaslessly (EIP-7702); the server signs for an Agent-Wallet buyer. Sandbox-by-default. Chain availability served by GET /api/escrow/chains.
`q402_escrow_release`	live mode	Buyer releases a locked escrow to the seller (gasless). Sandbox-by-default.
`q402_escrow_refund`	live mode	Permissionless refund to the buyer after the timeout / resolve window.
`q402_escrow_dispute`	live mode	A party disputes an open escrow (requires a named arbiter).
Triggers (RedStone)
`q402_redstone_feeds`	none	Which RedStone feeds this deployment can drive triggers off (NAV / price / RWA). Read-only.
`q402_redstone_trigger_create`	live mode	Arm a gasless payout that fires once when a RedStone feed crosses a threshold (edge-latched).
`q402_redstone_trigger_list`	live mode	List the Agent Wallet's RedStone triggers + their state.
`q402_redstone_trigger_cancel`	live mode	Permanently stop a RedStone trigger.
x402 (outbound)
`q402_x402_fetch`	live mode	Fetch any x402-gated URL and handle HTTP 402 automatically: validates Base USDC payment option, guards against excess spend, signs EIP-3009 TransferWithAuthorization, and retries with the correct payment header (PAYMENT-SIGNATURE for v2 servers, X-PAYMENT for v1 legacy). Non-402 responses pass through unchanged. Returns `status:"settled_no_delivery"` (`fundsMoved:true, retrySafe:false`) when a txHash in the response confirms funds moved but the seller returned an error. Returns `status:"settled_status_unknown"` (`fundsMovedUnknown:true, retrySafe:false`) when no settlement proof exists — funds may or may not have moved. Do NOT retry either outcome.
`q402_governance_analyze`	live mode	Paid governance proposal analysis. Paste a snapshot.org / snapshot.box link (or raw text) and optionally describe your priority in plain language; get a vote recommendation (For / Against / Abstain), five dimension ratings, and the reasoning. Pass `language` (e.g. `"zh"`) to receive results in the user's language. $0.05 USDC per call on Base via x402.

Note: q402_pay expects a 0x address; ENS is not resolved server-side, so resolve it client-side first. Per-chain Gas Tank balances + full TX history live in the dashboard (wallet-signature only).

x402 outbound payments (q402_x402_fetch)

Guards (three layers).

Guard	Env var	Default
Per-call spend cap	`Q402_MAX_AMOUNT_PER_CALL`	$200
Per-session cumulative cap	`Q402_X402_SESSION_CAP_USD`	$5
Two-phase consent	`consentToken`	required on payment

Result outcomes — read before summarizing to users.

Outcome	Fields	Meaning
`success: true`	`body`, `paid: true`, `payTo`, `amountUsd`	Content delivered, payment settled.
`success: false`, `needsConsent` set	`consentToken`, `preview`	No payment made. Re-call with `consentToken`.
`success: false`, `status: "settled_no_delivery"`	`fundsMoved: true`, `retrySafe: false`, `recipient`, `amount`, `txHash`, `guidance`	Funds confirmed left the wallet, content not delivered. Settlement is proven by `txHash` from the response. The seller accepted payment but returned an error. Do NOT tell the user "the payment didn't go through" — funds moved. Do NOT retry — that would make a second payment. Surface `amount`, `recipient`, `txHash`, and `guidance` to the user so they can reconcile with the seller.
`success: false`, `status: "settled_status_unknown"`	`fundsMovedUnknown: true`, `retrySafe: false`, `recipient`, `amount`, `txHash: null`, `guidance`	Settlement unknown — funds may or may not have moved. Payment header was sent but the response contained no settlement proof (no `txHash`). Do NOT assert that funds moved or didn't move. Do NOT retry with the same parameters — funds may have already moved. Surface `guidance` so the user can check their wallet balance and contact the seller.
`success: false` (other)	`error`	Payment blocked or rejected before settlement. No funds moved. Safe to retry.

Minimum working example.

{
  "url": "https://api.example.com/data",
  "method": "GET",
  "confirm": true
}

Governance analysis (q402_governance_analyze)

q402_governance_analyze analyzes a Snapshot governance proposal and returns a vote recommendation, five dimension scores, and the reasoning. $0.05 USDC per call on Base via x402.

Input parameters.

Parameter	Required	Description
`url`	one of	Snapshot proposal URL (snapshot.org or snapshot.box) or bare 0x proposal ID.
`proposalText`	one of	Raw proposal body text.
`proposalId`	one of	Snapshot proposal ID (`dao` defaults to `"snapshot"` when omitted).
`weights`	optional	Priority weights (0-100 integer each): `riskControl`, `decentralization`, `sustainability`, `communityImpact`. Mutually exclusive with `persona`.
`persona`	optional	Named analysis persona. Mutually exclusive with `weights`.
`language`	optional	BCP-47 language code for result display. Set to the user's conversation language, e.g. `"zh"` for Chinese, `"en"` for English (default). The server uses this to localize response fields; Claude also applies the built-in translation table so results are presented fully in the user's language.
`confirm`	required	Must be `true`. Attests user approved the $0.05 USDC charge.
`consentToken`	optional	Two-phase consent. Omit on first call; present the quote to the user and wait for their next independent message, then re-call with the token. Single-use, expires in ~120s.

Sandbox vs live mode

Sandbox default: q402_pay returns a fake txHash with success: false and sandbox: true. No funds, no quota.

Template q402_doctor writes to ~/.q402/mcp.env:

# ── API key - fill ONE (or both for auto-routing) ──
# Auto-routing (same for q402_pay AND q402_batch_pay):
#   chain="bnb" or "base" + Q402_TRIAL_API_KEY set  → Trial (free sponsored)
#   anything else                                    → Multichain (paid 12-chain)
# Batch ambiguity: 6+ recipient BNB/Base batch with Trial set returns
#   status="ambiguous" instead of executing - agent asks user to pick.
# Override per call with keyScope: "auto" | "trial" | "multichain".
Q402_TRIAL_API_KEY=                # BNB + Base sponsored Trial key (from /event; Avalanche trial ended)
Q402_MULTICHAIN_API_KEY=           # paid 12-chain key (per-chain Gas Tank)

# ── Signing path - pick ONE of Mode A / B / C ──
Q402_PRIVATE_KEY=                  # Mode A: real EOA pk (0x + 64 hex)
Q402_AGENTIC_PRIVATE_KEY=          # Mode B: exported Agent Wallet pk (from dashboard)
# Mode C: leave both PK lines blank. A Trial key enables one-shot Mode C
# payments; Multichain key required for recurring, batch, and bridge/OFT.
# Q402 signs with the server-managed Agent Wallet. Optionally:
# Q402_AGENT_WALLET_ADDRESS=0x...   # pin one of your wallets when you have multiple

# Live mode switch:
#   0 = sandbox (test mode, no funds move - every q402_pay returns a fake hash)
#   1 = real on-chain payments (live mode)
# Default 1. Safe because the gate only flips to live when an API key AND
# at least one valid signing path (A/B/C) are populated. Empty values
# fail the gate, so partial setups stay in sandbox with a hint.
Q402_ENABLE_REAL_PAYMENTS=1

# Pre-check trust-check (live mode). Triggers for first-time counterparties or
# payments >= $1. Fee: $0.02 per check; cached 7 days. Never blocks the main tx.
# Set Q402_DISABLE_PRECHECK=1 to opt out.

Anything missing for the resolved scope → automatic sandbox fallback with a hint pointing at what to set.

Sandbox responses carry success: false, sandbox: true, mode: "sandbox", method: "sandbox", plus a setupHint explaining why - four signals so a downstream summary can't claim success.

Hard caps

Env var	Default	Effect
`Q402_MAX_AMOUNT_PER_CALL`	`200`	Reject USDC/USDT/RLUSD calls with `amount > N` USD. Q (QuackAI) is exempt by design (your own token); the recipient allowlist + confirmation still apply to it.
`Q402_X402_SESSION_CAP_USD`	`5`	Per-session cumulative spend cap for `q402_x402_fetch` (USD). Blocked if the session total would exceed this value. Resets on MCP server restart.
`Q402_ALLOWED_RECIPIENTS`	off	Comma-separated address allowlist.
`Q402_BUILDER_CODE`	off	Base Builder Code for `q402_x402_fetch` on-chain attribution (ERC-8021 via x402 v2 `extensions.builder-code`).
`Q402_DISABLE_PRECHECK`	off	Set to `1` to opt out of the automatic pre-check trust-check on outgoing payments.

Configuration reference

Env var	Required for	Notes
`Q402_TRIAL_API_KEY`	live-pay (BNB + Base + Mantle)	BNB Chain + Base sponsored Trial key (permanent). Avalanche trial has ended — use Multichain for avax. Also covers Mantle during the limited-time window 2026-08-21~08-28 UTC+9. Free at https://q402.quackai.ai/event. Auto-routed for trial-eligible chains in both `q402_pay` and `q402_batch_pay` (≤5 recipients) when set. 6+ recipient trial batches return `status="ambiguous"` so the agent can ask the user how to split.
`Q402_MULTICHAIN_API_KEY`	live-pay (12-chain)	Paid 12-chain key. Get one at https://q402.quackai.ai/payment. Auto-routed for chains outside BNB/Base (including avax since the Avalanche trial ended) and for BNB/Base when no Trial key is set. Cap: 20 recipients per batch. Mode C one-shot pays accept Trial or Multichain; Multichain required for recurring, Mode C batch, and bridge/OFT.
`Q402_PRIVATE_KEY`	Mode A	Hex private key of your MetaMask EOA. Signer for local Mode A. Never share. Never paste in chat.
`Q402_AGENTIC_PRIVATE_KEY`	Mode B	Exported Agent Wallet hex private key from the dashboard (Agent tab → Export). Signs locally, but the signer is your dedicated Agent Wallet - MetaMask is never touched. Never share. Never paste in chat.
`Q402_AGENT_WALLET_ADDRESS`	Mode C (optional)	When you have multiple server-managed Agent Wallets (max 10 per owner), set this to the lowercased 0x… address of the one Q402 should spend from. Omit to use the default wallet. Ignored in Modes A/B.
`Q402_ENABLE_REAL_PAYMENTS`	live-pay	Set to `1` to opt in. Any other value (or unset) → sandbox.
`Q402_MAX_AMOUNT_PER_CALL`	optional	USD-equivalent cap for USDC/USDT/RLUSD. Defaults to `200`. Lower for tighter agent blast-radius. Q (QuackAI) is exempt by design (your own token).
`Q402_X402_SESSION_CAP_USD`	optional	Per-session cumulative spend cap for `q402_x402_fetch` (USD). Defaults to `5`. Resets on MCP server restart.
`Q402_ALLOWED_RECIPIENTS`	optional	Comma-separated lowercase addresses. Defaults to no allowlist.
`Q402_BUILDER_CODE`	optional	Base Builder Code (1–32 lowercase letters/numbers/underscores, e.g. `bc_fu2v7kgf`). Set to your registered Builder Code to attach on-chain ERC-8021 attribution to every `q402_x402_fetch` payment via the x402 `extensions.builder-code` field.
`Q402_DISABLE_PRECHECK`	optional	Set to `1` to disable the automatic pre-check trust-check that runs before outgoing payments in live mode. When unset (default), pre-check runs automatically for first-time counterparties and payments ≥ $1. The pre-check fee is $0.02; verdicts are cached 7 days (no repeat charge within TTL). The pre-check never blocks the main transaction.
`Q402_RELAY_BASE_URL`	optional	Defaults to `https://q402.quackai.ai/api`. Override for self-hosted Q402.

Supported chains

Chain	Chain ID	Token(s)	Notes
BNB Chain	56	USDC, USDT
Ethereum	1	USDC, USDT, RLUSD	L1 - gas is volatile, quote is a snapshot. RLUSD (Ripple USD, NY DFS regulated, decimals 18) Ethereum-only.
Avalanche C-Chain	43114	USDC, USDT
X Layer	196	USDC, USDT
Stable	988	USDT0 (USDC and USDT both alias)	Gas paid in USDT0.
Mantle	5000	USDC, USDT0	LayerZero OFT USDT0 since 2025-11-27.
Injective EVM	1776	USDC, USDT	Native Circle USDC (CCTP) live since 2026-06 + canonical Tether (USDT0).
Monad	143	USDC, USDT0	Native Circle USDC (CCTP V2) + USDT0 (LayerZero OFT).
Scroll	534352	USDC, USDT	zkEVM L2 - EIP-7702 live since the Euclid Phase 2 upgrade (2025-04-22).
Arbitrum One	42161	USDC, USDT	Optimistic rollup - same EIP-7702 signing path as Ethereum. CCIP bridge endpoint (eth ⇄ avax ⇄ arbitrum).
Base	8453	USDC, USDT	OP Stack L2 - same EIP-7702 signing path as Ethereum. Native Circle USDC + bridged Tether USD.
Robinhood Chain	4663	USDG	Arbitrum Nitro L2 - USDG only (Paxos Global Dollar, 6 decimals). Circle USDC / Tether are not canonical here; gasless USDG payments.

Why this exists

Hooks - programmable payment policies

Developer reference: docs/HOOKS.md - lifecycle, the Hook contract, every shipped hook with config + examples.

Repository

Source code: https://github.com/quackai-org/q402-mcp Issues / requests: https://github.com/quackai-org/q402-mcp/issues

License

Apache-2.0 - see LICENSE.