Incorrect App Configuration on Creation

“az webapp create ignores siteConfigPropertiesDictionary from the selected App Service stack # Describe the bug `az webapp create --runtime` resolves the selected runtime but does not apply the stack-specific site configuration supplied by the App Service stacks API in `siteConfigPropertiesDictionary`. The current observable failure is Windows Node 24. Its stack metadata includes: ```json { "siteConfigPropertiesDictionary": { "use32BitWorkerProcess": false } } ``` Node 24 is 64-bit only, but an app created with `--runtime "NODE:24LTS"` has `use32BitWorkerProcess: true`. A Node 24 probe then fails with HTTP 500. Changing only this property to `false` allows the same probe to run successfully as Node 24 x64. This should not be fixed with a Node 24-specific or Windows-only condition. The stacks API is the source of truth for runtime-specific site configuration on both Windows and Linux. Upcoming runtimes, including .NET 11 on Windows, will also require `use32BitWorkerProcess: false`, while Linux stacks may use the dictionary for other platform-appropriate settings. Every consumer of the stacks API should honor these properties generically so that adding or changing a stack does not require another Azure CLI release or runtime-specific branch. ## Related command ```text az webapp create ``` Related inspection and workaround commands: ```text az webapp list-runtimes az webapp config show az webapp config set --use-32bit-worker-process false ``` ## Errors The create command succeeds, but the resulting app is configured incorrectly: ```json { "nodeVersion": "", "use32BitWorkerProcess": true, "windowsFxVersion": null } ``` After deploying a no-dependency Node probe: ```text GET https://<app-name>.azurewebsites.net/ HTTP 500 <empty response body> ``` The identical probe on an otherwise identical app where only `use32BitWorkerProcess` is set to `false` returns: ```json { "nodeVersion": "v24.18.0", "architecture": "x64", "platform": "win32" } ``` ## Issue script & Debug output The following reproduces the configuration defect on a currently selected subscription. App names must be globally unique. ```powershell $location = "eastus2" $resourceGroup = "node24-cli-repro" $planName = "node24-cli-repro-plan" $appName = "node24-cli-repro-<unique-suffix>" az group create ` --name $resourceGroup ` --location $location az appservice plan create ` --resource-group $resourceGroup ` --name $planName ` --location $location ` --sku P0v3 ` --is-linux false az webapp list-runtimes ` --os-type windows ` --query "[?config=='NODE|24LTS']" az webapp create ` --resource-group $resourceGroup ` --plan $planName ` --name $appName ` --runtime "NODE:24LTS" ` --debug az webapp config show ` --resource-group $resourceGroup ` --name $appName ` --query "{nodeVersion:nodeVersion, windowsFxVersion:windowsFxVersion, use32BitWorkerProcess:use32BitWorkerProcess}" ``` Runtime discovery correctly returns Node 24: ```json [ { "config": "NODE|24LTS", "os": "Windows", "runtime": "Node", "version": "24.0 LTS" } ] ``` Relevant sanitized `--debug` output: ```text Will set appsetting {'name': 'WEBSITE_NODE_DEFAULT_VERSION', 'value': '~24'} PUT .../providers/Microsoft.Web/sites/<app-name>?api-version=2025-05-01 Request body: { "properties": { "siteConfig": { "appSettings": [ { "name": "WEBSITE_NODE_DEFAULT_VERSION", "value": "~24" } ], "alwaysOn": true }, "serverFarmId": "<redacted>" } } PUT .../providers/Microsoft.Web/sites/<app-name>/config/metadata?api-version=2025-05-01 Request body: { "properties": { "CURRENT_STACK": "node" } } ``` Neither request applies `use32BitWorkerProcess: false`. The resulting value is `true`: ```json { "nodeVersion": "", ”