AI Agents

AI agents write Testo tests well — and just as well port existing tests to Testo from other frameworks.

The fastest path to your first test: install the package (see Getting Started) and ask an agent to write or migrate tests, pointing it at llms-full.txt (see below).

How agents read Testo's docs

Testo publishes its documentation in the llms.txt format — a single machine-readable file an AI fetches instead of crawling HTML pages.

File	Content	When to use
/llms.txt	Page list with short descriptions and best practices.	Quick overview of available documentation.
/llms-full.txt	Full text of all documentation pages.	When the agent needs complete context for code generation.

Skills for agents

Alongside llms.txt, Testo ships a set of AI skills — short instructions that an agent (Claude Code, Codex, and others) loads on demand when it spots a matching task. They cover writing tests, migrating from other frameworks, parameterization, benchmarks, coverage, and other scenarios. The full list lives in the skills/ folder.

Roughly: llms.txt tells the agent what the API offers, while a skill tells it when to use what and where the pitfalls are. When triggered, a skill sends the agent off to read llms.txt for the details — so documentation isn't duplicated and skills don't go stale alongside the API.

Installation via the Composer plugin

To avoid copying skills by hand from vendor/testo/testo/skills/ into wherever your agent looks for them (.claude/skills/, .cursor/skills/, etc.), there's a dedicated package — llm/skills — that lays out skills from trusted Composer dependencies for you:

composer require --dev llm/skills

That's the whole setup. Composer will ask you to allow the plugin — answer y. After that, the plugin looks at the agent directories the project already has (.claude/, .cursor/, …), builds a configuration from them, and asks a single question to confirm it. Press Enter and it writes a skills.json at the project root and syncs the skills right away. Commit that file next to composer.json so the whole team gets the same setup.

If you'd rather make the choices yourself, or come back to them later, run the wizard:

composer skills:init

Either way you end up with something like this:

{
    "$schema": "https://raw.githubusercontent.com/roxblnfk/skills/master/resources/skills.schema.json",
    "target": ".agents/skills",
    "aliases": [".claude/skills", ".cursor/skills"],
    "auto-sync": true
}

Skills land in target — one real directory, tool-agnostic by default. Every path in aliases becomes a link to it (a junction on Windows, a symlink on POSIX), so each agent sees the same set of skills and no file is duplicated. With auto-sync on (the default), the skills are refreshed after every composer install and composer update; you can also run the sync by hand at any moment:

composer skills:update

Testo needs no extra configuration: the testo/* vendor is on the plugin's built-in trusted list, and a package you require directly is trusted anyway.

You don't have to do any of this by hand — hand the Set Up Agent Skills prompt to your agent and it installs the plugin, builds a skills.json around the agents this project uses, and checks that the skills landed.

The plugin isn't limited to Composer packages. composer skills:add <vendor>/<repo> registers a GitHub or GitLab repository as a skill source and fetches it right away — handy for your team's own skill collection.

Typical workflow

The same three steps work for new tests and for porting an existing suite:

1. Feed the context. Point the agent at llms-full.txt or paste the relevant section.
2. Describe the task. Provide the class or function you want to cover — or paste the old test you want to convert.
3. Review and run. Check the result and run vendor/bin/testo.

Example prompts

For ready-made, more elaborate prompts (project initialization, migrating an existing suite with bridge-rector, and more), see the Prompts page. The two below are quick, minimal starting points.

Writing tests from scratch:

Documentation: https://php-testo.github.io/llms-full.txt

Using the Testo PHP testing framework, write tests for the following class:

{paste your class here}

Migrating from another framework:

Documentation: https://php-testo.github.io/llms-full.txt

Rewrite the tests in the following folder to Testo. Keep the same assertions and data providers,
do not invent extra scenarios.

Tests folder: tests/Unit

Claude Code

Claude Code can fetch URLs during a conversation. Add an instruction to your project's CLAUDE.md:

When writing PHP tests, use the Testo framework.
Fetch the documentation before writing tests: https://php-testo.github.io/llms-full.txt

Claude Code will read this instruction and pull the documentation whenever it generates or migrates tests.

Cursor, Windsurf, and others

AI-powered code editors let you register external documentation as context. The typical approach is to add the documentation URL once and then reference it in chat.

• Cursor: Add the URL via Settings → Features → Docs → Add new doc. After indexing, reference it in chat with @Docs → select Testo.
• Windsurf: Paste the URL directly into a Cascade message.

For any IDE that doesn't support URL indexing, paste the contents of llms-full.txt into the chat as context.