Provision github azure federated identity

Overview

This skill provisions one Azure User Assigned Managed Identity (UAMI) per invocation for GitHub OIDC authentication — no long-lived credentials required. To cover multiple environments or both GitHub Actions and Copilot coding agent, run the script once per identity needed.

Each invocation creates or verifies (idempotent):

• A shared resource group (rg-github-<RepositoryName>-mi) for GitHub integration resources
• One User Assigned Managed Identity for either a GitHub Actions deployment environment or the GitHub Copilot coding agent
• A Federated Identity Credential on the identity, binding it to the specified GitHub context via OIDC
• RBAC role assignments at subscription scope:
  • Contributor — allows creating and managing Azure resources
  • User Access Administrator (with conditions) — allows role assignment but prevents granting Owner, User Access Administrator, or Role Based Access Control Administrator to any principal

If a resource already exists, the script skips creation and outputs the existing details.

Prerequisites

1. Azure PowerShell modules installed (the script validates this):

   • Az.Accounts ≥ 5.3.2
   • Az.Resources ≥ 9.0.0
   • Az.ManagedServiceIdentity ≥ 2.0.0

   Install missing modules with:

   Install-Module -Name Az.Accounts, Az.Resources, Az.ManagedServiceIdentity -Scope CurrentUser -Force
   

2. Authenticated Azure session — run Connect-AzAccount if not already authenticated.

3. The authenticated identity must have subscription-level permissions to:

   • Create resource groups
   • Create managed identities (Microsoft.ManagedIdentity/userAssignedIdentities/write)
   • Assign RBAC roles (Microsoft.Authorization/roleAssignments/write)

Script

The PowerShell script is bundled inside this skill's scripts/ subdirectory — it is not in the active workspace. Before running, resolve the absolute path as follows:

1. Note the absolute path of this SKILL.md file (available from the filePath attribute of the skill attachment in context)
2. Replace SKILL.md with scripts/Update-AzureUserAssignedManagedIdentityForGitHub.ps1 to get the full script path
3. Confirm the file exists by calling list_dir on the skill's scripts/ subfolder

Always use the full absolute path when invoking the script via #runInTerminal.

[!IMPORTANT] Don't search for the script in any other location. Do not create the script if you can't find it — 🛑 and report the issue instead.

Script parameters

Parameter	Required	Default	Description
RepositoryName	Yes	—	GitHub repository name (not the full org/repo path)
Type	No	actions	Identity purpose: actions (GitHub Actions environment) or codingAgent (Copilot coding agent)
Environment	No	test	GitHub environment name — only used when Type is actions
GitHubOrganization	No	PlagueHO	GitHub organization or user account owning the repository
SubscriptionId	No	Current context	Azure subscription ID to deploy resources into
Location	No	New Zealand North	Azure region for the resource group and identity
ResourceGroupName	No	rg-github-<RepositoryName>-mi	Override the resource group name
IdentityName	No	Computed (see naming)	Override the UAMI name
RbacRoles	No	@('Contributor','User Access Administrator')	RBAC role names to assign at subscription scope — overrides the default set
RemoveUnlistedRoles	No	$false	Remove any subscription-scope role assignments for this identity that are absent from -RbacRoles
Force	No	$false	Skip interactive confirmation prompts

Resource naming

Resource	Default name
Resource group	rg-github-<RepositoryName>-mi
UAMI — actions type	mi-actions-<RepositoryName>-<Environment>-env
UAMI — codingAgent type	mi-coding-agent-<RepositoryName>
Federated credential — actions	<GitHubOrganization>-<RepositoryName>-<Environment>
Federated credential — codingAgent	<GitHubOrganization>-<RepositoryName>-copilot

Use -ResourceGroupName or -IdentityName to override the computed defaults when needed.

How to use this skill

Step 1 — Gather required information

Ask the user for (or infer from context):

• RepositoryName (required) — GitHub repo name
• Type — actions for a deployment environment, codingAgent for Copilot coding agent
• Environment — GitHub environment name (required when Type is actions; e.g. test, staging, prod)
• GitHubOrganization — if not the default PlagueHO
• SubscriptionId — if targeting a specific Azure subscription

For multiple environments or both GitHub Actions and Copilot agent access, plan to run the script once per identity required.

Step 2 — Run the script

Use #runInTerminal to execute from a PowerShell session already authenticated to Azure.

GitHub Actions identity for a single environment:

.\scripts\Update-AzureUserAssignedManagedIdentityForGitHub.ps1 `
    -RepositoryName 'my-repo' `
    -Type 'actions' `
    -Environment 'test'

GitHub Actions identities for multiple environments (run once per environment):

foreach ($env in @('test', 'staging', 'prod')) {
    .\scripts\Update-AzureUserAssignedManagedIdentityForGitHub.ps1 `
        -RepositoryName 'my-repo' `
        -Type 'actions' `
        -Environment $env `
        -Force
}

Copilot coding agent identity:

.\scripts\Update-AzureUserAssignedManagedIdentityForGitHub.ps1 `
    -RepositoryName 'my-repo' `
    -Type 'codingAgent'

Full invocation with all common parameters:

.\scripts\Update-AzureUserAssignedManagedIdentityForGitHub.ps1 `
    -RepositoryName 'my-repo' `
    -Type 'actions' `
    -Environment 'prod' `
    -GitHubOrganization 'MyOrg' `
    -SubscriptionId '12345678-1234-1234-1234-123456789012' `
    -Location 'East US' `
    -Force

Custom RBAC roles (overrides defaults):

.\scripts\Update-AzureUserAssignedManagedIdentityForGitHub.ps1 `
    -RepositoryName 'my-repo' `
    -Type 'actions' `
    -Environment 'prod' `
    -RbacRoles @('Contributor')

Remove roles no longer required:

.\scripts\Update-AzureUserAssignedManagedIdentityForGitHub.ps1 `
    -RepositoryName 'my-repo' `
    -Type 'actions' `
    -Environment 'prod' `
    -RbacRoles @('Contributor') `
    -RemoveUnlistedRoles

Preview changes without applying (-WhatIf):

.\scripts\Update-AzureUserAssignedManagedIdentityForGitHub.ps1 `
    -RepositoryName 'my-repo' `
    -Type 'actions' `
    -Environment 'test' `
    -WhatIf

Step 3 — Configure GitHub repository secrets and environments

After each script run, it outputs the values needed for GitHub.

Repository-level secrets (Settings → Secrets and variables → Actions):

Secret	Value
AZURE_TENANT_ID	Azure AD tenant ID (printed by script)
AZURE_SUBSCRIPTION_ID	Azure subscription ID (printed by script)

Per-environment secret (Settings → Environments → <env name> → Secrets):

Secret	Value
AZURE_CLIENT_ID	clientId of the managed identity for that environment (printed by script)

For the Copilot coding agent, create a GitHub environment named copilot and set AZURE_CLIENT_ID under it.

Step 4 — Use the managed identity in GitHub Actions

permissions:
  id-token: write   # Required for OIDC token request
  contents: read

jobs:
  deploy:
    runs-on: ubuntu-latest
    environment: test   # Must match the environment name used when creating the identity
    steps:
      - uses: azure/login@v2
        with:
          client-id: ${{ secrets.AZURE_CLIENT_ID }}
          tenant-id: ${{ secrets.AZURE_TENANT_ID }}
          subscription-id: ${{ secrets.AZURE_SUBSCRIPTION_ID }}

For Copilot coding agent workflows, use environment: copilot.

Idempotency

Running the script multiple times against the same repository is safe. Each resource (resource group, UAMI, federated credential, role assignment) is checked before creation. If it already exists, it is skipped and its current details are included in the output. Re-running is the standard approach to update a subset of environments or verify state.

RBAC role management

• Default roles: Contributor and User Access Administrator.
• Pass -RbacRoles to specify a different set of roles — this replaces the defaults entirely for that invocation.
• By default, roles already assigned to the identity but absent from -RbacRoles are left intact.
• Pass -RemoveUnlistedRoles to also remove any subscription-scope role assignments for the identity that are not listed in -RbacRoles.
• User Access Administrator is always assigned with a condition preventing the identity from granting Owner, User Access Administrator, or Role Based Access Control Administrator to any principal, regardless of whether the role list was customised.

Edge cases and when to pause

• RepositoryName not provided — only mandatory parameter; ask before running.
• Type not specified — ask whether the identity is for GitHub Actions (actions) or Copilot coding agent (codingAgent).
• Environment not specified for actions type — ask for the environment name; each environment requires a separate script execution.
• Multiple environments — confirm the list before running; one execution is needed per environment.
• Non-default SubscriptionId — confirm which subscription to use if it differs from the current Azure context.
• -Force flag — do not pass unless the user explicitly requests skipping prompts; without it the script confirms each resource creation interactively.
• -RemoveUnlistedRoles — confirm with the user before using; roles assigned outside this script could be intentional.
• Role assignment failures — the script retries up to 3 times. If all retries fail, surface the error and ask the user to verify Azure permissions before retrying.

Security notes

• No static credentials are created. All authentication uses short-lived OIDC tokens issued by GitHub at runtime.
• User Access Administrator is granted with a condition expression that prevents assignment of Owner, User Access Administrator, or Role Based Access Control Administrator, following the principle of least privilege.
• Script output includes tenant and subscription IDs. These are non-secret identifiers but should not be committed to public repositories — store them as GitHub secrets.