Fix azureterraform_azapi_get to return 400 BadRequest for invalid resource type or API version (#2657)

* Enhance error handling in AzApiDocsService and update status code in AzApiDocsGetCommandTests

* Add changelog entry for azapi_get 400 BadRequest fix

* Change `GetResourceApiVersions.ResourceVisitor` in BicepSchema tools to throw `InvalidDataException` for unknown resource types (#2840)

Change `GetResourceApiVersions.ResourceVisitor` in the BicepSchema tools to throw `InvalidDataException` for unknown resource types

`GetResourceApiVersions` threw a bare `Exception` (and an unhandled `KeyNotFoundException` when the provider existed but the resource type did not), which `AzApiDocsService` normalized via a broad catch-all that also misclassified real server-side faults as `400 BadRequest`. Throw `InvalidDataException` at the source instead, consistent with `LoadSingleResource`, and drop the catch-all so unexpected exceptions surface as `500`.

---------

Co-authored-by: vcolin7 <victor.y.asi@gmail.com>

Author: liuwuliuyun

servers/Azure.Mcp.Server/changelog-entries/yunliu1-azapi-get-bad-request.yaml

@@ -0,0 +1,3 @@
+changes:
+  - section: "Bugs Fixed"
+    description: "Fixed `azureterraform_azapi_get` returning `500 InternalServerError` for invalid resource type or API version inputs. The tool now returns `400 BadRequest` with an actionable message, enabling agents to auto-correct and retry with valid inputs."

tools/Azure.Mcp.Tools.AzureTerraform/src/Commands/AzApiDocsGetCommand.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT License.
 
+using System.IO;
 using System.Net;
 using Azure.Mcp.Tools.AzureTerraform.Models;
 using Azure.Mcp.Tools.AzureTerraform.Options;
@@ -55,6 +56,12 @@ protected override AzApiDocsOptions BindOptions(ParseResult parseResult)
         };
     }
 
+    protected override HttpStatusCode GetStatusCode(Exception ex) => ex switch
+    {
+        InvalidDataException => HttpStatusCode.BadRequest,
+        _ => base.GetStatusCode(ex)
+    };
+
     public override async Task<CommandResponse> ExecuteAsync(
         CommandContext context,
         ParseResult parseResult,

tools/Azure.Mcp.Tools.AzureTerraform/tests/Azure.Mcp.Tools.AzureTerraform.Tests/AzApiDocsGetCommandTests.cs

@@ -136,7 +136,7 @@ public async Task ExecuteAsync_ServiceThrows_HandlesException()
 
         var response = await ExecuteCommandAsync("--resource-type", "Microsoft.Fake/nonexistent");
 
-        Assert.NotEqual(HttpStatusCode.OK, response.Status);
+        Assert.Equal(HttpStatusCode.BadRequest, response.Status);
     }
 
     [Theory]

tools/Azure.Mcp.Tools.BicepSchema/src/Services/ResourceProperties/ResourceVisitor.cs

@@ -86,12 +86,13 @@ public string[] GetResourceApiVersions(string resourceTypeName)
     {
         (string providerName, _, _) = ResourceParser.ParseResourceType(resourceTypeName);
 
-        if (!GetAllResourceTypesAndVersionsByProvider().TryGetValue(providerName, out ProviderResourceTypes? provider))
+        if (!GetAllResourceTypesAndVersionsByProvider().TryGetValue(providerName, out ProviderResourceTypes? provider)
+            || !provider.ResourceTypes.TryGetValue(resourceTypeName.ToLowerInvariant(), out UniqueResourceType? uniqueResourceType))
         {
-            throw new Exception($"Resource type {resourceTypeName} not found.");
+            throw new InvalidDataException($"Resource type {resourceTypeName} not found.");
         }
 
-        return [.. provider.ResourceTypes[resourceTypeName.ToLowerInvariant()].ApiVersions];
+        return [.. uniqueResourceType.ApiVersions];
     }
 
     public TypesDefinitionResult LoadSingleResource(string resourceTypeName, string apiVersion)

tools/Azure.Mcp.Tools.BicepSchema/tests/Azure.Mcp.Tools.BicepSchema.Tests/GetSchemaTests.cs

@@ -33,7 +33,7 @@ public void GetResourcePropertySchema_ShouldThrowOnNotFound()
         SchemaGenerator.ConfigureServices(serviceCollection);
         IServiceProvider serviceProvider = serviceCollection.BuildServiceProvider();
 
-        var exception = Assert.Throws<Exception>(() =>
+        var exception = Assert.Throws<InvalidDataException>(() =>
         {
             TypesDefinitionResult result = SchemaGenerator.GetResourceTypeDefinitions(serviceProvider, "Microsoft.Unknown/virtualRandom");
             _ = SchemaGenerator.GetResponse(result);