Experimental. This is a 0.x package and its surface is not settled. The package name, the binary, the namespace and the environment variables all changed in one cut on 2026-08-06. The tool names and the shapes they answer in can move the same way. Pin a commit where you depend on it.
A local MCP server (plain PHP) that helps coding agents implement, review and verify TYPO3 work for the three audiences that do it: the core contributor, the extension author and the site developer. It establishes the project and installation the agent is working in, supplies current, version-bound TYPO3 knowledge, and hands task-specific workflows to the skills that own them.
It answers for TYPO3 12.4, 13.4, 14.3 and main. A statement that does not hold on all of them names the ones it does, so an LTS is never handed a convention that only the development line has.
The MCP client launches it as a subprocess over stdio, so there is no server to host, no network exposure and no auth to configure — the process boundary is the trust boundary. It reads: nothing is written into the TYPO3 installation it is pointed at, and nothing on the machine is started as a side effect of a lookup.
Requirements: PHP 8.2+ and Composer. One standalone checkout serves every project on the machine and stays out of each project's dependencies:
git clone https://github.com/TYPO3/dev-companion.git typo3-dev-companion
composer install --working-dir=typo3-dev-companion
cd /path/to/your/project
/absolute/path/to/typo3-dev-companion/bin/typo3-dev-companion installinstall writes into the directory it is run in, so the last two lines are run
from the root of the project the agent works in. A project can require the
package instead, composer require "typo3/dev-companion:@dev", and run
vendor/bin/typo3-dev-companion install; the manual has that case.
install writes the typo3-dev-companion entry into the project's .mcp.json
and publishes the task skills to .agents/skills — the two locations a client
finds without being configured for it. --agent=<id> writes them where that
client actually reads them instead.
It is also the only supported way to get the skills: a copy of skills/ taken
out of this repository by hand is missing the references/base.md the installer
writes into each of them, and every skill opens on that file.
The manual reads as a site at typo3.github.io/dev-companion, and as files in documentation/:
- Usage — the path from the install to the first answered question, and behind it every client the install supports and the task workflows it publishes.
- Server — what it can be asked, one page per tool, and where each answer comes from.
- Contributing — working on this repository rather than using it.
- Records — how feedback from a real session becomes an improvement.
The conventions every session here works under are AGENTS.md.