DDEV MCP Inspector

The Model Context Protocol Inspector running as a service inside your DDEV project. Test stdio, SSE, and Streamable HTTP MCP servers from any framework — Craft CMS, Laravel, Drupal, Node, Python, anything you build inside DDEV — without installing Node on the host.

Why this exists. When you’re building or debugging an MCP server, you need a client that speaks every transport, lets you inspect tool/resource/prompt registries, and runs requests against your server. The official Inspector does exactly that. This add-on packages it as a turnkey DDEV service so it shares your project’s network, hostnames, and TLS — no port juggling, no host Node, no npx race conditions.

Install

ddev add-on get michtio/ddev-mcp-inspector
ddev restart

The first ddev restart builds the image and pre-installs the Inspector — about 30 seconds. Every subsequent ddev start brings it up in roughly five.

Open the UI

ddev mcp-inspector

Opens the client UI at https://<project>.ddev.site:6275.

Connect to an MCP server

Open the client UI, pick a transport, and connect. Below are working snippets for the common cases.

Craft CMS plugin (e.g. cortex)

In the Inspector UI: Transport: STDIO, Command: docker, Arguments: (one of these depending on your composer_root)

exec -i ddev-<project>-web php /var/www/html/craft cortex/serve         # composer_root = "" (default)
exec -i ddev-<project>-web php /var/www/html/<dir>/craft cortex/serve   # composer_root = "<dir>"

craft is a PHP script (not in $PATH, not chmod +x) so it has to be invoked via php with its absolute path. Check composer_root in your .ddev/config.yaml to find the right directory.

Tip: if you’ll connect repeatedly, drop a one-line wrapper at .ddev/commands/web/craft-mcp that does php /var/www/html/<your-composer-root>/craft cortex/serve — then the inspector arguments simplify to exec -i ddev-<project>-web craft-mcp.

Laravel (Boost or any Artisan-driven MCP)

Command: docker, Arguments: exec -i ddev-<project>-web php artisan boost:mcp

Drupal (drush-mcp or a custom Drush command)

Command: docker, Arguments: exec -i ddev-<project>-web drush mcp:serve

Node MCP server in your project

Command: docker, Arguments: exec -i ddev-<project>-web node /var/www/html/path/to/server.mjs

Python MCP server in your project

Command: docker, Arguments: exec -i ddev-<project>-web python /var/www/html/path/to/server.py

Streamable HTTP / SSE servers

In the Inspector UI: Transport: Streamable HTTP (or SSE) and enter the URL — typically your project’s HTTPS endpoint plus the route the server listens on. From inside DDEV containers, the Inspector reaches services on the project’s internal Docker network.

Why docker exec instead of running the server locally?

The Inspector container is on the project’s Docker network and has access to the host’s Docker socket — so it spawns the MCP server as a sibling-container process. That means:

• No need to install Node / PHP / Python / framework runtimes on your host.
• The MCP server runs in the same environment as your app (same DB, same file paths, same env vars).
• One ddev start brings everything up.

Commands

ddev mcp-inspector              # open the client UI in your browser (default)
ddev mcp-inspector status       # is the inspector running and reachable?
ddev mcp-inspector logs         # tail the inspector container logs
ddev mcp-inspector urls         # print all client/proxy URLs
ddev mcp-inspector version      # show the pinned MCP Inspector version

Endpoints

The proxy is HTTPS-only externally — modern browsers refuse mixed-content fetches from an HTTPS UI to an HTTP proxy.

Configuration

Environment variables on the mcp-inspector service in .ddev/docker-compose.mcp-inspector.yaml:

To pin a different Inspector version, edit .ddev/mcp-inspector-build/Dockerfile and change MCP_INSPECTOR_VERSION, then ddev restart.

Removing

ddev add-on remove mcp-inspector
ddev restart

This removes the docker-compose service, the build context, and the host command. The DDEV-built image will be cleaned up by ddev delete -O or docker image prune.

Requirements

• DDEV >= v1.24.10
• Docker

Sponsoring

If this add-on saves you time on MCP development, consider sponsoring on GitHub or Buy Me a Coffee. Sponsors keep this maintained and the daily upstream-regression CI running.

Contributing

See CONTRIBUTING.md for development setup, test instructions, and PR guidelines.

License

MIT — see LICENSE.

Credits

• Model Context Protocol — Anthropic et al.
• MCP Inspector — upstream tool this add-on packages.
• DDEV — local-development platform this add-on extends.