diff --git a/servers/Azure.Mcp.Server/changelog-entries/jairmyree-fix-healthmodels-entity-get.yaml b/servers/Azure.Mcp.Server/changelog-entries/jairmyree-fix-healthmodels-entity-get.yaml
new file mode 100644
index 0000000000..a8da71caad
--- /dev/null
+++ b/servers/Azure.Mcp.Server/changelog-entries/jairmyree-fix-healthmodels-entity-get.yaml
@@ -0,0 +1,4 @@
+changes:
+  - section: "Bugs Fixed"
+    description: |
+      Fixed `monitor_healthmodels_entity_get` returning HTTP 400 (Bad Request) when querying entity health. The tool now uses a supported `Microsoft.CloudHealth` control-plane API version (`2025-05-01-preview`), and the data-plane request URL is built correctly by joining the dataplane endpoint with a path separator and URL-encoding the entity name.
diff --git a/tools/Azure.Mcp.Tools.Monitor/src/Services/MonitorHealthModelService.cs b/tools/Azure.Mcp.Tools.Monitor/src/Services/MonitorHealthModelService.cs
index 28ca9db20f..1cbdeaf24d 100644
--- a/tools/Azure.Mcp.Tools.Monitor/src/Services/MonitorHealthModelService.cs
+++ b/tools/Azure.Mcp.Tools.Monitor/src/Services/MonitorHealthModelService.cs
@@ -14,7 +14,7 @@ namespace Azure.Mcp.Tools.Monitor.Services;
 public class MonitorHealthModelService(ITenantService tenantService, IHttpClientFactory httpClientFactory)
     : BaseAzureService(tenantService), IMonitorHealthModelService
 {
-    private const string ApiVersion = "2023-10-01-preview";
+    private const string ApiVersion = "2025-05-01-preview";
     private readonly IHttpClientFactory _httpClientFactory = httpClientFactory ?? throw new ArgumentNullException(nameof(httpClientFactory));
     private readonly ITenantService _tenantService = tenantService ?? throw new ArgumentNullException(nameof(tenantService));
 
@@ -45,7 +45,7 @@ public async Task<JsonNode> GetEntityHealth(
         ValidateRequiredParameters((nameof(entity), entity), (nameof(healthModelName), healthModelName), (nameof(resourceGroupName), resourceGroupName), (nameof(subscription), subscription));
 
         string dataplaneEndpoint = await GetDataplaneEndpointAsync(subscription, resourceGroupName, healthModelName, cancellationToken);
-        string entityHealthUrl = $"{dataplaneEndpoint}api/entities/{entity}/history";
+        string entityHealthUrl = $"{dataplaneEndpoint.TrimEnd('/')}/api/entities/{Uri.EscapeDataString(entity)}/history";
 
         string healthResponseString = await GetDataplaneResponseAsync(entityHealthUrl, cancellationToken);
         return JsonNode.Parse(healthResponseString) ?? throw new Exception("Failed to parse health response to JSON.");
diff --git a/tools/Azure.Mcp.Tools.Monitor/tests/Azure.Mcp.Tools.Monitor.Tests/MonitorCommandTests.cs b/tools/Azure.Mcp.Tools.Monitor/tests/Azure.Mcp.Tools.Monitor.Tests/MonitorCommandTests.cs
index f3d363ce6e..34ade78463 100644
--- a/tools/Azure.Mcp.Tools.Monitor/tests/Azure.Mcp.Tools.Monitor.Tests/MonitorCommandTests.cs
+++ b/tools/Azure.Mcp.Tools.Monitor/tests/Azure.Mcp.Tools.Monitor.Tests/MonitorCommandTests.cs
@@ -35,6 +35,7 @@ public sealed class MonitorCommandTests : RecordedCommandTestsBase
     private string? _storageAccountName;
     private string? _appInsightsName;
     private string? _bingWebTestName;
+    private string? _healthModelName;
 
     public MonitorCommandTests(ITestOutputHelper output, TestProxyFixture fixture, LiveServerFixture liveServerFixture)
         : base(output, fixture, liveServerFixture)
@@ -91,6 +92,7 @@ public override async ValueTask InitializeAsync()
         _storageAccountName = $"{Settings.ResourceBaseName}mon";
         _appInsightsName = $"{Settings.ResourceBaseName}-ai";
         _bingWebTestName = $"{Settings.ResourceBaseName}-bing-test";
+        _healthModelName = $"{Settings.ResourceBaseName}-health";
 
         if (TestMode == TestMode.Playback)
         {
@@ -519,6 +521,42 @@ public override async ValueTask DisposeAsync()
     //     }
     // }
 
+    #region HealthModels Integration Tests
+
+    [Fact]
+    public async Task Should_Get_Entity_Health()
+    {
+        var result = await CallToolAsync(
+            "monitor_healthmodels_entity_get",
+            new()
+            {
+                { "subscription", Settings.SubscriptionId },
+                { "resource-group", Settings.ResourceGroupName },
+                { "health-model", _healthModelName },
+                { "entity", "root" }
+            });
+
+        Assert.NotNull(result);
+    }
+
+    [Theory]
+    [InlineData("--invalid-param")]
+    [InlineData("--subscription invalidSub")]
+    [InlineData("--subscription sub --resource-group rg")] // Missing required entity/health-model
+    public async Task Should_Return400_WithInvalidHealthModelInput(string args)
+    {
+        var result = await CallToolAsync(
+            "monitor_healthmodels_entity_get",
+            new()
+            {
+                { "args", args }
+            });
+
+        Assert.NotEqual(200, result?.GetProperty("status").GetInt32() ?? 500);
+    }
+
+    #endregion
+
     #region WebTests Integration Tests
 
     [Fact]