Circle Agent Stack Mcp

io.github.kinancePublished by GitHub account kinancev0.1.1Updated Oct 24, 2026

Circle Agent Stack for AI agents: USDC wallets, spend policies, transfers, and x402 nanopayments.

The publisher's own server: Circle

VerifiedSTDIODesktop onlyFinanceBusiness & Commerce

Overview

AI-generated overview

A local MCP server that lets an assistant create Circle USDC wallets, set spend policies, send USDC transfers and pay x402-priced endpoints.

What you can do
Create and list agent wallets (dev, hosted or smart) and check USDC balances with recent transactions for a wallet. Set spend policies such as a daily cap, an x402 cap and allow or block lists. Send USDC to an on-chain address. Pay an x402-priced endpoint within a maximum price and return its response.
When to use it
Useful when an assistant should manage Circle agent wallets and make small USDC payments, including paying per-call x402 endpoints, with spending limits applied first.
Requirements
Runs locally via npx (Node.js). Requires the Circle CLI installed globally and authenticated with circle login, plus a Circle API key supplied in the CIRCLE_API_KEY environment variable. Network access to Circle and to x402 endpoints is needed.
Before you install
The Circle API key carries spend authority and moves real funds; keep it out of version control. Transfers and x402 payments send USDC on-chain and cannot be undone. Set the daily and x402 caps and an allowlist before enabling automated payments, and start with dev wallets rather than mainnet. The README notes v0.1 shells out to the Circle CLI.

Installation

In SourceWeft

  1. Open Circle Agent Stack Mcp in the dashboard and add it to a workspace.
  2. Enable the server for the chats that should use its tools.

Desktop only via STDIO. STDIO servers start a local process, so they need the SourceWeft desktop host.

Other MCP clients

Follow the launch instructions in the repository.

README

circle-agent-stack-mcp

MCP server for Circle's Agent Stack. Create wallets, set spend policies, send USDC, and pay x402-priced endpoints — all from a tool call.

bash
npx circle-agent-stack-mcp

Tools

ToolWhat it does
circle_wallet_createCreate an agent wallet (dev/hosted/smart)
circle_wallet_listList wallets with USDC balances
circle_balanceBalance + last 10 txns for a wallet
circle_policy_setSet daily cap, x402 cap, allow/block lists
circle_transfer_usdcSend USDC to an on-chain address
circle_x402_payPay an x402-priced endpoint and return its response

Quickstart

You need the Circle CLI installed and authenticated:

bash
npm install -g @circle-fin/circle-clicircle loginexport CIRCLE_API_KEY=your_key_here

Claude Desktop

json
{  "mcpServers": {    "circle": {      "command": "npx",      "args": ["-y", "circle-agent-stack-mcp"],      "env": {        "CIRCLE_API_KEY": "your_key_here"      }    }  }}

Claude Code

bash
claude mcp add circle -- npx -y circle-agent-stack-mcp

Example

You: Create a dev wallet called eva-treasury, set a $5 daily cap and $0.10 x402 cap,     then fetch today's BTC signal from the x402 endpoint at https://signals.example.co/btc
Claude:→ circle_wallet_create("eva-treasury", type="dev")  { wallet_id: "wal_abc123", address: "0x..." }
→ circle_policy_set("wal_abc123", daily_cap_usdc=5, x402_cap_usdc=0.10)  { status: "applied" }
→ circle_x402_pay("wal_abc123", "https://signals.example.co/btc", max_price_usdc=0.10)  { signal: "LONG", confidence: 0.72, price_paid_usdc: 0.05 }
Today's BTC signal: LONG (72% confidence). Paid $0.05.

Self-hosting with x402 paywall

http-server.ts wraps the same tools behind an x402 paywall — agents pay per call in USDC rather than using an API key. Useful if you want to expose Circle tooling as a paid service.

bash
CIRCLE_PAYOUT_ADDRESS=0x... npm run start:http

To test the x402 flow locally, run the toy demo server in examples/x402-demo-server.mjs.

How it works

v0.1 shells out to the Circle CLI for all operations. This keeps auth handling out of this repo and avoids reimplementing the API client before the tool surface is validated. v0.2 will switch to direct HTTP via @circle-fin/circle-sdk.

Security

Your Circle API key has spend authority. Always:

  • Set daily_cap_usdc before enabling automated payments
  • Start on type="dev" wallets, not mainnet
  • Review the allowlist before moving to production
  • Don't commit CIRCLE_API_KEY

Roadmap

  • circle_nanopayment_stream — streaming x402 payments for per-token billing
  • circle_skills_list / circle_skills_call — Circle Skills marketplace
  • Direct HTTP API mode (v0.2) — remove CLI dependency
  • Multi-chain — EURC, CCTP cross-chain transfers

Related

Source: README.md at commit 7f69d6a

Tools

0
SourceWeft has not started this package in its sandbox yet, so its tools are not known.

Version history

1
  1. v0.1.1LatestSep 16, 2026

Score

50% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

  • Reached in the last 30 days25 pts

    Keep the endpoint answering the MCP handshake; SourceWeft probes it every 30 days.

  • Auth declared10 pts

    Declare the credential headers in the registry entry, or keep the endpoint answering the probe so its auth can be classified.

  • Tools listed15 pts

    Answer tools/list without a credential, or ship a package that starts in a sandbox without one.

  • DescriptionRequired15 pts
  • Logo10 pts
  • Documentation15 pts
  • License10 pts

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