Circle Agent Stack MCP

Name: Circle Agent Stack MCP
Author: kinance

by kinanceversion 0.1.1i★ –iRuns on your computer

Registry nameio.github.kinance/circle-agent-stack-mcp

Install

Overview

Description from the maker (original English)

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

PopNx MCP’s three pillars

These three are never merged into one score: opinions, measurements and popularity are different things.

User voiceiNo reviews yetReviews open together with accounts in a later step
Our basic checksi1 of 1 passedChecked from public information; code not scanned yet
UsageiNot measured yet★ –

What you can do with it

We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.

Connection: Runs on your computer
Transport: stdio
Category: Other
You need to fill in: CIRCLE_API_KEY

Install

Pick the AI app you use, then copy the settings.

Before you install

Basic checks: 1 of 1 passed
Runs on your computer with your user’s permissions (files, network, apps).
You fill in yourself: CIRCLE_API_KEY

Values marked secret are keys to your account. Never share them or paste them into a chat.

You need

npmNode.js installed (for the npx command)

Which app do you use?

ClaudeClaude CodeCursorVS CodeChatGPT

Pick your app above. We remember it, so next time the button says “Install in …”.

Open Claude Desktop → Settings → Developer → Edit Config, and paste this into claude_desktop_config.json

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

Run this in your terminal

claude mcp add circle-agent-stack --env CIRCLE_API_KEY=your-value -- npx -y circle-agent-stack-mcp

Fill in the empty values before running it.

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

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

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "circle-agent-stack": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "circle-agent-stack-mcp"
      ],
      "env": {
        "CIRCLE_API_KEY": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

This one runs on your computer, and ChatGPT can only connect to servers on the internet. Pick another app.

Your choice stays on this device in a cookie; no account needed.

Values you fill in

CIRCLE_API_KEY secret required env
Your Circle API key from developers.circle.com

These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

What it can do

Runs on your computer; the tool list appears in your AI app after you install it.

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 6, 2026

✓ Pass
Maker matches the repo
The registry name was verified with the GitHub account kinance, which owns the repo
… Not checked yet
Still maintained
We have not read this repo from GitHub yet
… Not checked yet
Has a licence
We have not read this repo from GitHub yet
– Not applicable
Endpoint responds
This one runs on your computer; there is no internet endpoint
– Not applicable
Sign-in with OAuth
Runs on your computer and uses local settings instead
… Not checked yet
No hidden instructions in tool descriptions
Runs on your computer; we can only read tool lists from internet endpoints

Compared with others in Otheri

More stars than 0% of the other 32461 servers in this category
Published to the registry more recently than 11% of the other 32461 servers in this category
Basic checks equal to or better than 100% of the other 32461 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Common questions

Is Circle Agent Stack MCP safe?

It passed 1 of 1 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.

What keys or codes does it need?

You need to fill in: CIRCLE_API_KEY

Does it run on my computer or in the cloud?

It runs on your computer. Your AI app starts it when needed, and data does not pass through the maker’s servers (unless it calls an online service itself).

Is it still maintained?

The GitHub repo last changed –, and the latest version (0.1.1) reached the registry 5 months ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. You also need Node.js on your computer.

What can I use instead?

In the same category: Spec Driven Development, Remote Desktop Commander, dotnet-mcp

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README from the maker

Open the README

Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.

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.

npx circle-agent-stack-mcp

Tools

Tool	What it does
`circle_wallet_create`	Create an agent wallet (dev/hosted/smart)
`circle_wallet_list`	List wallets with USDC balances
`circle_balance`	Balance + last 10 txns for a wallet
`circle_policy_set`	Set daily cap, x402 cap, allow/block lists
`circle_transfer_usdc`	Send USDC to an on-chain address
`circle_x402_pay`	Pay an x402-priced endpoint and return its response

Quickstart

You need the Circle CLI installed and authenticated:

npm install -g @circle-fin/circle-cli

circle login export CIRCLE_API_KEY=your_key_here

Claude Desktop

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

Claude Code

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.

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

Circle Agent Stack MCP

Overview

PopNx MCP’s three pillars

What you can do with it

Install

Before you install

Values you fill in

What it can do

Basic checksi

Maker matches the repo

Still maintained

Has a licence

Endpoint responds

Sign-in with OAuth

No hidden instructions in tool descriptions

Compared with others in Otheri

Common questions

Alternatives

Spec Driven Development

Remote Desktop Commander

dotnet-mcp

README from the maker

circle-agent-stack-mcp

Tools

Quickstart

Claude Desktop

Claude Code

Example

Self-hosting with x402 paywall

How it works

Security

Roadmap

Related