Add commands for managing organization custom property definitions

[MariusStorhaug]

Context

GitHub organizations can define custom properties as a schema for repository metadata. These property definitions control what custom properties are available, their data types, allowed values, default values, and whether they are required. This is separate from the property values set on individual repositories.

Custom property definitions are used to enforce organizational standards — for example, requiring every repository to declare an Environment (production / development) or a Team owner. Automation and governance workflows depend on these definitions being manageable programmatically.

Request

The GitHub PowerShell module currently has no commands for managing organization-level custom property definitions. The only existing command is Get-GitHubRepositoryCustomProperty, which reads property values from a single repository — not the property schema from the organization.

Desired capability

Organization administrators should be able to create, read, update, and remove custom property definitions for their organization using PowerShell commands. This includes specifying the property name, value type, description, allowed values, default values, required status, and editability settings.

Platform data types

The GitHub platform supports five custom property value types:

Value type	API value_type	Description
string	string	Free-form text
single_select	single_select	Single selection from an ordered list of allowed values
multi_select	multi_select	Multiple selections from an ordered list of allowed values
true_false	true_false	Boolean — "true" or "false"
url	url	A URL string

Property definition schema

Each custom property definition includes:

Field	Type	Description
property_name	string	Name of the property. Characters: a-z, A-Z, 0-9, _, -, $, #. No spaces. Max 75 characters.
value_type	string	One of: string, single_select, multi_select, true_false, url
required	boolean	Whether the property is required on all repositories
default_value	string, array, or null	Default value applied to repositories without an explicit value
description	string or null	Short description of the property
allowed_values	string[] or null	Ordered list of allowed values (for single_select and multi_select). Max 200 values.
values_editable_by	string or null	Who can edit values: org_actors, org_and_repo_actors, or null
require_explicit_values	boolean	Whether repositories must have an explicitly set value (no inheriting default)

REST API endpoints

The following REST API endpoints are involved:

Method	Endpoint	Description
GET	/orgs/{org}/properties/schema	Get all custom properties for an organization
GET	/orgs/{org}/properties/schema/{custom_property_name}	Get a custom property for an organization
PUT	/orgs/{org}/properties/schema/{custom_property_name}	Create or update a custom property for an organization
PATCH	/orgs/{org}/properties/schema	Create or update custom properties for an organization (batch)
DELETE	/orgs/{org}/properties/schema/{custom_property_name}	Remove a custom property for an organization

Additionally, the following endpoints manage property values on repositories at the organization level:

Method	Endpoint	Description
GET	/orgs/{org}/properties/values	List custom property values for organization repositories
PATCH	/orgs/{org}/properties/values	Create or update custom property values for organization repositories (batch, max 30 repos)

Acceptance criteria

• All five value types (string, single_select, multi_select, true_false, url) are supported when creating or updating property definitions
• Property definitions can be listed for an organization
• A single property definition can be retrieved by name
• Property definitions can be created with all supported fields (name, type, description, allowed values, default value, required, editability, require explicit values)
• Property definitions can be updated
• Property definitions can be removed
• Repository custom property values can be set at the organization level (batch)
• Commands follow the module's naming convention (Verb-GitHubOrganizationCustomProperty)
• Required permissions are documented (custom properties org admin for schema management, write for value setting)

Related issues

• Expose CustomProperties as a PSCustomObject instead of Name-Value array #564 — Expose CustomProperties as a PSCustomObject instead of Name-Value array (covers the repository-level reading side)