> ## Documentation Index
> Fetch the complete documentation index at: https://docs.metriport.com/llms.txt
> Use this file to discover all available pages before exploring further.

# ParameterDefinition

> Base StructureDefinition for ParameterDefinition Type: The parameters to the module. This collection specifies both the input and output parameters. Input parameters are provided by the caller as part of the $evaluate operation. Output parameters are included in the GuidanceResponse.

## Properties

| Name          | Required | Type                                                   | Description                                   |
| ------------- | -------- | ------------------------------------------------------ | --------------------------------------------- |
| id            | No       | string                                                 | Unique id for inter-element referencing       |
| extension     | No       | [Extension](/medical-api/fhir/data-types/extension)\[] | Additional content defined by implementations |
| name          | No       | code                                                   | Name used to access the parameter value       |
| use           | Yes      | code                                                   | in / out                                      |
| min           | No       | integer                                                | Minimum cardinality                           |
| max           | No       | string                                                 | Maximum cardinality (a number of \*)          |
| documentation | No       | string                                                 | A brief description of the parameter          |
| type          | Yes      | code                                                   | What type of value                            |
| profile       | No       | canonical                                              | What profile the value is expected to be      |