dev-companion

# TYPO3 Dev Companion > **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. It serves the three audiences that do it: the core contributor, the extension author and the site developer. It establishes the project and installation the agent works in, and supplies current, version-bound TYPO3 knowledge. It 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 never gets 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. It writes nothing into the TYPO3 installation it points at, and it starts nothing on the machine as a side effect of a lookup. ## Quickstart Requirements: **PHP 8.2+** and Composer. One standalone checkout serves every project on the machine and stays out of each project's dependencies: ```bash 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 install ``` `install` writes into the directory it runs in, so the last two lines 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`. Those are the two locations a client finds without configuration 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 lacks the `references/base.md` the installer writes into each of them. Every skill opens on that file. ## Documentation The manual reads as a site at [typo3.github.io/dev-companion](https://typo3.github.io/dev-companion/), and as files in [documentation/](documentation/readme.rst): - [Usage](documentation/usage/readme.rst) — the path from the install to the first answered question. Behind it every client the install supports and the task workflows it publishes. - [Server](documentation/server/readme.rst) — what a caller can ask it, one page per tool, and where each answer comes from. - [Contributing](documentation/contributing/readme.rst) — working on this repository rather than using it. - [Records](documentation/records/readme.rst) — how feedback from a real session becomes an improvement. The conventions every session here works under are [AGENTS.md](AGENTS.md).