A new skills plugin for Claude Code, Cursor, and Codex
Developers are increasingly building alongside AI coding assistants rather than reaching for documentation as a first step. Tools like Claude Code, Cursor, and Codex can scaffold a feature in minutes, summarise an unfamiliar codebase, or wire up an integration before you have finished your coffee. The catch is that their output is only as reliable as the context they have to work with. Without it, agents have been shown to hallucinate package names, reference endpoints that no longer exist, and produce integrations that look reasonable on the page but fall apart the moment you run them.
To help with this, we have released the ideal-postcodes/skills plugin. It is a set of agent skills that give Claude Code, Cursor, and Codex the right information about our products, so the code they produce for Ideal Postcodes integrations works on the first attempt.
The skill packages quickstarts, common gotchas, and reference material into a format the agent can load automatically when it recognises a relevant task. Instead of relying on whatever the model picked up during training, the agent has authoritative, current information to work from.
The plugin includes five skills, each focused on a specific way of working with our services:
ideal-postcodes-address-finder is for the multi-country address autocomplete widget, covering everything from installation through to populated form fields.
ideal-postcodes-postcode-lookup handles the classic UK pattern of postcode in, address dropdown out.
ideal-postcodes-api-integration covers direct HTTP integration, including authentication, the /postcodes, /addresses, /udprn, and /autocomplete endpoints, client libraries, and error handling.
ideal-postcodes-react provides the React bindings for the widgets, for teams working in that ecosystem.
ideal-postcodes-cli documents the idpc CLI, which is useful for managing keys, cleansing addresses, and resolving partial queries from the terminal.
To install the plugin, run the following command from inside your repository:
npx skills add ideal-postcodes/skills
Once installed, the skills are available to whichever supported agent is active in that project. The mechanism varies slightly between tools, but the experience for you is the same.
Claude Code installs the skills under .claude/skills/ and loads them automatically when you open the repository. The Claude Code integration guide has more detail.
Cursor picks the skills up through the .cursor-plugin/ manifest. See the Cursor integration guide.
Codex works through the .codex-plugin/ manifest. The Codex integration guide covers the setup.
Once the plugin is installed, you can ask things like:
What's the npm install command for the Ideal Postcodes Address Finder?
Add Ideal Postcodes Address Finder to the billing address fields.
How do I add UK postcode lookup to a checkout form using Ideal Postcodes?
The agent reaches for the relevant skill before answering, so the package name, configuration options, and form field handling all match how our widgets are built.
The plugin ships with a shared test key by default, limited to five lookups per day, which is intended for evaluation only. When you are ready to move beyond that, you can sign up for a free trial to receive a production key and swap it into your configuration.
Before deploying anywhere public, it is worth restricting the key using Allowed URLs, so the key can only be used from domains you control.
If you would like to try the plugin, the repository is public and we welcome feedback. As more development work happens through coding agents, we think skills like these will become a standard part of how products are integrated, and we're glad to be early to that shift.
Skills source code: github.com/ideal-postcodes/skills
AI integration hub: Build with AI Guide
Complete reference: llms.txt
If you have questions, you can reach the team at support@ideal-postcodes.co.uk or file an issue on GitHub