sumup

A collection of Agent Skills 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.

Claude Code

Install using the plugin marketplace:

/plugin marketplace add sumup/sumup-skills
/plugin install sumup@sumup

Cursor

Install from the Cursor Marketplace or add manually via Settings > Rules > Add Rule > Remote Rule (Github) with sumup/sumup-skills.

Gemini CLI

Install the extension from GitHub:

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

OpenAI Codex

Install using the Codex plugin marketplace:

codex plugin marketplace add sumup/sumup-skills

Kiro

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

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 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

Clone this repo and copy the skill folders into the appropriate directory for your agent:

Agent	Skill Directory	Docs
Claude Code	~/.claude/skills/	docs
Cursor	~/.cursor/skills/	docs
Gemini CLI	~/.gemini/extensions/	docs
OpenCode	~/.config/opencode/skills/	docs
OpenAI Codex	~/.codex/skills/	docs
Pi	~/.pi/agent/skills/	docs

Skills

Install using the npx skills CLI:

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	Implementing SumUp checkout flows end-to-end across Checkouts API, Card Widget, Hosted Checkout, recurring tokenization, and terminal/cloud reader checkouts
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	Planning and executing SumUp API/SDK upgrades and migrations across server and mobile SDK surfaces
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	Configuring and using the SumUp MCP server (https://mcp.sumup.com/mcp) from MCP-capable clients
sumup-testing	Setting up sandbox test merchants, running success/failure scenarios (including amount = 11), and validating end-to-end checkout behavior

Resources

• SumUp Developer Documentation
• SumUp API Reference
• SumUp MCP Server