How to add some fixed variables to a plugin

[xunbu]

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1. Is this request related to a challenge you're experiencing? Tell me about your story.

How to add some fixed variables to a plugin? I am developing a plugin and hope to have some methods to add common "plugin variables" globally or to plugins in the workflow. However, it seems that currently, it is only possible to add parameters to tools, and they need to be filled in separately each time they are used.

2. Additional context or comments

No response

[dosubot[bot]]

Dify doesn't currently support true global or workflow-level plugin variables. Plugin parameters are defined per tool, and each tool instance manages its own parameter values. However, you have two main options to achieve "fixed" variables:

1. Set default values in your plugin/tool parameter definitions. When you define a parameter in your PluginParameter or ToolParameter, you can specify a default value. This value will be used unless the user overrides it in the workflow or tool configuration. This is the closest built-in way to have a fixed value for a parameter, but it's still scoped per tool instance and not shared globally across tools or workflows.
   See PluginParameter definition

2. Leverage workflow/environment variables (VariablePool). Dify's VariablePool lets you define environment, system, or conversation variables at the workflow level. In the workflow editor, you can wire a tool parameter to one of these shared variables instead of entering a constant value. This way, you set the value once (as a workflow variable), and all tools referencing it will use the same value.
   See VariablePool usage

Limitations:

• There is no mechanism for a variable that is truly global across all workflows and plugins; you must wire variables per workflow.
• Each tool parameter must still be configured to use the variable, but you only set the value once per workflow.

If you need true global plugin variables (shared across all workflows and tools), you would need to extend Dify's core to support this, possibly by adding a global variable registry and updating the parameter resolution logic to check it.

Let me know if you want a step-by-step example for either approach!

To reply, just mention @dosu.

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