write-script-php_skill

Overview

This skill guides you to write PHP scripts that run on the Windmill platform. It explains the required script structure, how to declare resource types, and how to list runtime library dependencies so your script runs as a deployable Windmill task. It also covers the basic CLI steps to generate metadata and push scripts to the platform.

How this skill works

Scripts must begin with the PHP opening tag and expose a main function that Windmill will call with parameters. Credentials and configuration are modeled as resource objects; you must redefine resource classes in your script (guarded by a class_exists check) so Windmill can marshal those resources into typed parameters. External libraries are declared as in-file comments and are auto-installed for the runtime.

When to use it

• When authoring PHP tasks intended to run on Windmill
• When your script needs platform-managed credentials or typed configuration
• When you want to declare runtime third-party libraries for the script
• When preparing scripts to be converted into webhooks, UIs, or workflows on the platform
• When validating that resource types exist and are correctly typed before use

Best practices

• Always start the file with <?php and define a main function with typed parameters
• Redefine resource classes exactly using the resource type names and protect definitions with class_exists
• Declare each external dependency as a single-line comment before main (one package per line)
• Keep resource classes minimal: only include fields Windmill will supply (host, port, user, password, etc.)
• Run metadata generation and push commands after writing or changing scripts to update the platform's catalogs

Example use cases

• A PHP task that reads credentials from a Postgresql resource and runs a query
• A webhook handler that uses guzzlehttp/guzzle to call an external API
• A scheduled workflow step that requires stripe/stripe-php for billing operations
• A simple string-processing script that returns structured results via the main function
• A self-hosted deployment where scripts are stored in a folder and synced to Windmill