sumup — Claude Code plugin: what it does, how to install

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# SumUp Skills

[![Documentation][docs-badge]](https://developer.sumup.com)
[![License](https://img.shields.io/github/license/sumup/sumup-go)](./LICENSE)

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A collection of [Agent Skills](https://agentskills.io/home) for building SumUp payment integrations across card-present (terminal) and card-not-present (online) checkout flows.

## Installing

These skills work with agents that support the Agent Skills standard, including Claude Code, Cursor, Gemini CLI, OpenCode, OpenAI Codex, and Pi.

The packaged integrations include skills and hosted MCP configuration. Sign in with SumUp through your assistant to use account tools. Skills can be used without connecting an account. For the complete client setup guide, see [Plugins](https://developer.sumup.com/tools/llms/plugins/) and [MCP Server](https://developer.sumup.com/tools/llms/mcp-server/).

### Claude Code

Run in your terminal:

```bash
claude plugin marketplace add sumup/sumup-skills
claude plugin install sumup@sumup
claude plugin list
```

Inside Claude Code, you can also use `/plugin marketplace add sumup/sumup-skills` and `/plugin install sumup@sumup`. Follow the install summary's reload instructions, then open `/mcp` to authorize the SumUp server in your browser.

### Cursor

For teams, import `https://github.com/sumup/sumup-skills` from **Dashboard > Plugins & MCPs > Team Marketplaces > Add Marketplace > Import from Repo**, then add and install the SumUp plugin. See [Cursor plugins](https://cursor.com/docs/plugins).

For an individual setup, install the skills with `npx skills add https://github.com/sumup/sumup-skills` and configure the [hosted MCP connection](https://developer.sumup.com/tools/llms/mcp-server/).

### Gemini CLI

Install the extension from GitHub:

```bash
gemini extensions install https://github.com/sumup/sumup-skills --ref=main
gemini extensions list
```

Start a new Gemini CLI session and run `/mcp auth sumup` to authorize the hosted server.

### OpenAI Codex

Install using the Codex plugin marketplace:

```bash
codex plugin marketplace add sumup/sumup-skills
codex plugin add sumup@sumup
codex plugin list
```

Start a new Codex session to load the plugin and complete SumUp authorization when prompted. Plugins work in the Codex CLI and Codex in the ChatGPT desktop app. For the Codex IDE extension, install standalone skills and configure MCP directly.

To pull plugin updates, run `codex plugin marketplace upgrade sumup`, then start a new session.

### Kiro

Import this repository as a custom power from Kiro: **Powers > Add Custom Power > Import power from GitHub**.

Activate the power and authorize its SumUp MCP connection when prompted. For local testing, use **Import power from a folder** and select this repository root.

### Agent Skills Discovery

Agents and tools that support the [Agent Skills Discovery RFC](https://github.com/cloudflare/agent-skills-discovery-rfc) can discover the SumUp skills from:

`https://developer.sumup.com/.well-known/agent-skills/index.json`

Use this URL in clients that accept a discovery index or start from `https://developer.sumup.com` when the client discovers well-known skill indexes automatically.

### Clone / Copy

For a skills-only installation, clone this repo and copy the folders under `skills/` into the appropriate directory for your agent. This does not configure MCP:

| Agent | Skill Directory | Docs |
|-------|-----------------|------|
| Claude Code | `~/.claude/skills/` | [docs](https://code.claude.com/docs/en/skills) |
| Cursor | `~/.cursor/skills/` | [docs](https://cursor.com/docs/context/skills) |
| Gemini CLI | `~/.gemini/skills/` | [docs](https://geminicli.com/docs/cli/skills/) |
| OpenCode | `~/.config/opencode/skills/` | [docs](https://opencode.ai/docs/skills/) |
| OpenAI Codex | `~/.codex/skills/` | [docs](https://developers.openai.com/codex/skills/) |
| Pi | `~/.pi/agent/skills/` | [docs](https://github.com/badlogic/pi-mono/tree/main/packages/coding-agent#skills) |

## Skills

Install using the `npx skills` CLI:

```bash
npx skills add https://github.com/sumup/sumup-skills
```

Skills are contextual and auto-loaded based on your conversation. When a request matches a skill's triggers, the agent loads and applies that skill.

| Skill | Useful for |
|-------|------------|
| [sumup](./skills/sumup/) | Implementing SumUp checkout flows end-to-end across Checkouts API, Card Widget, Hosted Checkout, recurring tokenization, and terminal/cloud reader checkouts |
| [sumup-best-practices](./skills/sumup-best-practices/) | Choosing the right integration path and security posture across Hosted Checkout, Card Widget, Checkouts API, mobile SDKs, terminal SDKs, and Cloud API |
| [upgrade-sumup](./skills/upgrade-sumup/) | Planning and executing SumUp API/SDK upgrades and migrations across server and mobile SDK surfaces |
| [sumup-debug](./skills/sumup-debug/) | Diagnosing and fixing common integration failures such as webhook signature mismatches, scope issues, session expiry, widget mount failures, and duplicate references |
| [sumup-mcp](./skills/sumup-mcp/) | Configuring and using the SumUp MCP server (`https://mcp.sumup.com/mcp`) from MCP-capable clients |
| [sumup-testing](./skills/sumup-testing/) | Setting up sandbox test merchants, running success/failure scenarios (including `amount = 11`), and validating end-to-end checkout behavior |

## Verify the Setup

Ask your assistant: "Use the SumUp skills to explain how to build a Hosted Checkout integration."

After authorizing MCP, try a read-only request: "Use the SumUp MCP tools to show my merchant profile."

Use a [sandbox merchant account](https://developer.sumup.com/online-payments/#getting-a-sandbox-merchant-account) before testing payment workflows. If tools are missing or authorization fails, see [MCP troubleshooting](https://developer.sumup.com/tools/llms/mcp-server/#troubleshooting).

## Resources

- [SumUp Developer Documentation](https://developer.sumup.com)
- [SumUp API Reference](https://developer.sumup.com/api)
- [SumUp MCP Server](https://mcp.sumup.com/mcp)

[docs-badge]: https://img.shields.io/badge/SumUp-documentation-white.svg?logo=data:image/svg+xml;base64,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