From 0c735c1585488eb4cb5a6bb500ddb1397242ee82 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Tue, 3 Feb 2026 10:58:43 +0000
Subject: [PATCH 01/16] Initial plan


From 9b89729c8d825876595651b5afefae4c356aa611 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Tue, 3 Feb 2026 11:00:16 +0000
Subject: [PATCH 02/16] Add common_properties_error_client_test.rs with tests
 for create_for_user_defined_error and get_for_predefined_error

Co-authored-by: antkmsft <41349689+antkmsft@users.noreply.github.com>
---
 .../common_properties_error_client_test.rs    | 133 ++++++++++++++++++
 1 file changed, 133 insertions(+)
 create mode 100644 packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs

diff --git a/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs
new file mode 100644
index 000000000..9fc792d7c
--- /dev/null
+++ b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs
@@ -0,0 +1,133 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+//
+// Licensed under the MIT License. See License.txt in the project root for license information.
+
+use azure_core::credentials::{AccessToken, TokenCredential, TokenRequestOptions};
+use azure_core::time::OffsetDateTime;
+use azure_core::Result;
+use spector_armcommon::models::{ConfidentialResource, ConfidentialResourceProperties};
+use spector_armcommon::CommonPropertiesClient;
+use std::collections::HashMap;
+use std::sync::Arc;
+
+#[derive(Debug)]
+struct FakeTokenCredential {
+    pub token: String,
+}
+
+impl FakeTokenCredential {
+    pub fn new(token: String) -> Self {
+        FakeTokenCredential { token }
+    }
+}
+
+#[async_trait::async_trait]
+impl TokenCredential for FakeTokenCredential {
+    async fn get_token(
+        &self,
+        _scopes: &[&str],
+        _options: Option<TokenRequestOptions<'_>>,
+    ) -> Result<AccessToken> {
+        Ok(AccessToken::new(
+            self.token.clone(),
+            OffsetDateTime::now_utc(),
+        ))
+    }
+}
+
+fn create_client() -> CommonPropertiesClient {
+    CommonPropertiesClient::new(
+        "http://localhost:3000",
+        Arc::new(FakeTokenCredential::new("fake_token".to_string())),
+        "00000000-0000-0000-0000-000000000000".to_string(),
+        None,
+    )
+    .unwrap()
+}
+
+fn get_valid_confidential_resource() -> ConfidentialResource {
+    ConfidentialResource {
+        id: Some("/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/test-rg/providers/Azure.ResourceManager.CommonProperties/confidentialResources/resource".to_string()),
+        location: Some("eastus".to_string()),
+        name: Some("resource".to_string()),
+        properties: Some(ConfidentialResourceProperties {
+            provisioning_state: Some("Succeeded".to_string()),
+            username: Some("testuser".to_string()),
+        }),
+        tags: Some(HashMap::from([(
+            "tagKey1".to_string(),
+            "tagValue1".to_string(),
+        )])),
+        type_prop: Some("Azure.ResourceManager.CommonProperties/confidentialResources".to_string()),
+        ..Default::default()
+    }
+}
+
+#[tokio::test]
+async fn create_for_user_defined_error() {
+    let resource = ConfidentialResource {
+        location: Some("eastus".to_string()),
+        properties: Some(ConfidentialResourceProperties {
+            username: Some("testuser".to_string()),
+            ..Default::default()
+        }),
+        ..Default::default()
+    };
+
+    let client = create_client();
+    let resp = client
+        .get_common_properties_error_client()
+        .create_for_user_defined_error("test-rg", "resource", resource.try_into().unwrap(), None)
+        .await
+        .unwrap();
+
+    let confidential_resource: ConfidentialResource = resp.into_model().unwrap();
+    let expected_resource = get_valid_confidential_resource();
+    
+    assert_eq!(expected_resource.id, confidential_resource.id);
+    assert_eq!(expected_resource.location, confidential_resource.location);
+    assert_eq!(expected_resource.name, confidential_resource.name);
+    assert_eq!(expected_resource.tags, confidential_resource.tags);
+    assert_eq!(expected_resource.type_prop, confidential_resource.type_prop);
+
+    let expected_properties = expected_resource.properties.unwrap();
+    let confidential_properties = confidential_resource.properties.unwrap();
+    assert_eq!(
+        expected_properties.provisioning_state,
+        confidential_properties.provisioning_state,
+    );
+    assert_eq!(
+        expected_properties.username,
+        confidential_properties.username,
+    );
+}
+
+#[tokio::test]
+async fn get_for_predefined_error() {
+    let client = create_client();
+    let resp = client
+        .get_common_properties_error_client()
+        .get_for_predefined_error("test-rg", "resource", None)
+        .await
+        .unwrap();
+
+    let confidential_resource: ConfidentialResource = resp.into_model().unwrap();
+    let expected_resource = get_valid_confidential_resource();
+    
+    assert_eq!(expected_resource.id, confidential_resource.id);
+    assert_eq!(expected_resource.location, confidential_resource.location);
+    assert_eq!(expected_resource.name, confidential_resource.name);
+    assert_eq!(expected_resource.tags, confidential_resource.tags);
+    assert_eq!(expected_resource.type_prop, confidential_resource.type_prop);
+
+    let expected_properties = expected_resource.properties.unwrap();
+    let confidential_properties = confidential_resource.properties.unwrap();
+    assert_eq!(
+        expected_properties.provisioning_state,
+        confidential_properties.provisioning_state,
+    );
+    assert_eq!(
+        expected_properties.username,
+        confidential_properties.username,
+    );
+}

From d7b7dc51e5e87b3f9f6a4eb25176d23798f99faa Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Tue, 3 Feb 2026 11:08:31 +0000
Subject: [PATCH 03/16] Fix trailing whitespace in test file

Co-authored-by: antkmsft <41349689+antkmsft@users.noreply.github.com>
---
 .../tests/common_properties_error_client_test.rs              | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs
index 9fc792d7c..311d261f1 100644
--- a/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs
+++ b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs
@@ -83,7 +83,7 @@ async fn create_for_user_defined_error() {
 
     let confidential_resource: ConfidentialResource = resp.into_model().unwrap();
     let expected_resource = get_valid_confidential_resource();
-    
+
     assert_eq!(expected_resource.id, confidential_resource.id);
     assert_eq!(expected_resource.location, confidential_resource.location);
     assert_eq!(expected_resource.name, confidential_resource.name);
@@ -113,7 +113,7 @@ async fn get_for_predefined_error() {
 
     let confidential_resource: ConfidentialResource = resp.into_model().unwrap();
     let expected_resource = get_valid_confidential_resource();
-    
+
     assert_eq!(expected_resource.id, confidential_resource.id);
     assert_eq!(expected_resource.location, confidential_resource.location);
     assert_eq!(expected_resource.name, confidential_resource.name);

From 5a1bbe011711e2fdb42d6511c1a240584f5387dd Mon Sep 17 00:00:00 2001
From: Anton Kolesnyk <antkmsft@users.noreply.github.com>
Date: Tue, 10 Feb 2026 14:10:24 -0800
Subject: [PATCH 04/16] Make fixes

---
 .../common_properties_error_client_test.rs    | 51 +++----------------
 1 file changed, 7 insertions(+), 44 deletions(-)

diff --git a/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs
index 311d261f1..64596207d 100644
--- a/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs
+++ b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs
@@ -3,6 +3,7 @@
 // Licensed under the MIT License. See License.txt in the project root for license information.
 
 use azure_core::credentials::{AccessToken, TokenCredential, TokenRequestOptions};
+use azure_core::http::StatusCode;
 use azure_core::time::OffsetDateTime;
 use azure_core::Result;
 use spector_armcommon::models::{ConfidentialResource, ConfidentialResourceProperties};
@@ -75,59 +76,21 @@ async fn create_for_user_defined_error() {
     };
 
     let client = create_client();
-    let resp = client
+    let rsp = client
         .get_common_properties_error_client()
         .create_for_user_defined_error("test-rg", "resource", resource.try_into().unwrap(), None)
-        .await
-        .unwrap();
+        .await;
 
-    let confidential_resource: ConfidentialResource = resp.into_model().unwrap();
-    let expected_resource = get_valid_confidential_resource();
-
-    assert_eq!(expected_resource.id, confidential_resource.id);
-    assert_eq!(expected_resource.location, confidential_resource.location);
-    assert_eq!(expected_resource.name, confidential_resource.name);
-    assert_eq!(expected_resource.tags, confidential_resource.tags);
-    assert_eq!(expected_resource.type_prop, confidential_resource.type_prop);
-
-    let expected_properties = expected_resource.properties.unwrap();
-    let confidential_properties = confidential_resource.properties.unwrap();
-    assert_eq!(
-        expected_properties.provisioning_state,
-        confidential_properties.provisioning_state,
-    );
-    assert_eq!(
-        expected_properties.username,
-        confidential_properties.username,
-    );
+    assert_eq!(rsp.unwrap_err().http_status(), Some(StatusCode::BadRequest));
 }
 
 #[tokio::test]
 async fn get_for_predefined_error() {
     let client = create_client();
-    let resp = client
+    let rsp = client
         .get_common_properties_error_client()
         .get_for_predefined_error("test-rg", "resource", None)
-        .await
-        .unwrap();
-
-    let confidential_resource: ConfidentialResource = resp.into_model().unwrap();
-    let expected_resource = get_valid_confidential_resource();
-
-    assert_eq!(expected_resource.id, confidential_resource.id);
-    assert_eq!(expected_resource.location, confidential_resource.location);
-    assert_eq!(expected_resource.name, confidential_resource.name);
-    assert_eq!(expected_resource.tags, confidential_resource.tags);
-    assert_eq!(expected_resource.type_prop, confidential_resource.type_prop);
+        .await;
 
-    let expected_properties = expected_resource.properties.unwrap();
-    let confidential_properties = confidential_resource.properties.unwrap();
-    assert_eq!(
-        expected_properties.provisioning_state,
-        confidential_properties.provisioning_state,
-    );
-    assert_eq!(
-        expected_properties.username,
-        confidential_properties.username,
-    );
+    assert_eq!(rsp.unwrap_err().http_status(), Some(StatusCode::NotFound));
 }

From 99477d15f7e973d8e017cf1d5caf75f0218b8c08 Mon Sep 17 00:00:00 2001
From: Anton Kolesnyk <antkmsft@users.noreply.github.com>
Date: Tue, 10 Feb 2026 15:06:25 -0800
Subject: [PATCH 05/16] Clippy

---
 .../common_properties_error_client_test.rs     | 18 ------------------
 1 file changed, 18 deletions(-)

diff --git a/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs
index 64596207d..57f327479 100644
--- a/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs
+++ b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs
@@ -46,24 +46,6 @@ fn create_client() -> CommonPropertiesClient {
     .unwrap()
 }
 
-fn get_valid_confidential_resource() -> ConfidentialResource {
-    ConfidentialResource {
-        id: Some("/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/test-rg/providers/Azure.ResourceManager.CommonProperties/confidentialResources/resource".to_string()),
-        location: Some("eastus".to_string()),
-        name: Some("resource".to_string()),
-        properties: Some(ConfidentialResourceProperties {
-            provisioning_state: Some("Succeeded".to_string()),
-            username: Some("testuser".to_string()),
-        }),
-        tags: Some(HashMap::from([(
-            "tagKey1".to_string(),
-            "tagValue1".to_string(),
-        )])),
-        type_prop: Some("Azure.ResourceManager.CommonProperties/confidentialResources".to_string()),
-        ..Default::default()
-    }
-}
-
 #[tokio::test]
 async fn create_for_user_defined_error() {
     let resource = ConfidentialResource {

From a0cfacafe1bbee16e8f7bb98e335d384a666f41a Mon Sep 17 00:00:00 2001
From: Anton Kolesnyk <antkmsft@users.noreply.github.com>
Date: Tue, 10 Feb 2026 15:32:00 -0800
Subject: [PATCH 06/16] Clippy

---
 .../tests/common_properties_error_client_test.rs                 | 1 -
 1 file changed, 1 deletion(-)

diff --git a/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs
index 57f327479..c3220d96a 100644
--- a/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs
+++ b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs
@@ -8,7 +8,6 @@ use azure_core::time::OffsetDateTime;
 use azure_core::Result;
 use spector_armcommon::models::{ConfidentialResource, ConfidentialResourceProperties};
 use spector_armcommon::CommonPropertiesClient;
-use std::collections::HashMap;
 use std::sync::Arc;
 
 #[derive(Debug)]

From 3515a362eb2a367748f6eca79e10f2548c7cdd3a Mon Sep 17 00:00:00 2001
From: Anton Kolesnyk <antkmsft@users.noreply.github.com>
Date: Thu, 12 Feb 2026 11:43:49 -0800
Subject: [PATCH 07/16] Remove code duplication

---
 .../common-properties/tests/common/mod.rs     | 44 ++++++++++++++++
 .../common_properties_error_client_test.rs    | 46 ++--------------
 ...properties_managed_identity_client_test.rs | 52 +++----------------
 3 files changed, 55 insertions(+), 87 deletions(-)
 create mode 100644 packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common/mod.rs

diff --git a/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common/mod.rs b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common/mod.rs
new file mode 100644
index 000000000..019b29181
--- /dev/null
+++ b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common/mod.rs
@@ -0,0 +1,44 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+//
+// Licensed under the MIT License. See License.txt in the project root for license information.
+
+use azure_core::credentials::{AccessToken, TokenCredential, TokenRequestOptions};
+use azure_core::time::OffsetDateTime;
+use azure_core::Result;
+use spector_armcommon::CommonPropertiesClient;
+use std::sync::Arc;
+
+#[derive(Debug)]
+struct FakeTokenCredential {
+    pub token: String,
+}
+
+impl FakeTokenCredential {
+    pub fn new(token: String) -> Self {
+        FakeTokenCredential { token }
+    }
+}
+
+#[async_trait::async_trait]
+impl TokenCredential for FakeTokenCredential {
+    async fn get_token(
+        &self,
+        _scopes: &[&str],
+        _options: Option<TokenRequestOptions<'_>>,
+    ) -> Result<AccessToken> {
+        Ok(AccessToken::new(
+            self.token.clone(),
+            OffsetDateTime::now_utc(),
+        ))
+    }
+}
+
+pub fn create_client() -> CommonPropertiesClient {
+    CommonPropertiesClient::new(
+        "http://localhost:3000",
+        Arc::new(FakeTokenCredential::new("fake_token".to_string())),
+        "00000000-0000-0000-0000-000000000000".to_string(),
+        None,
+    )
+    .unwrap()
+}
diff --git a/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs
index c3220d96a..8f6379e1c 100644
--- a/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs
+++ b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs
@@ -2,48 +2,10 @@
 //
 // Licensed under the MIT License. See License.txt in the project root for license information.
 
-use azure_core::credentials::{AccessToken, TokenCredential, TokenRequestOptions};
+mod common;
+
 use azure_core::http::StatusCode;
-use azure_core::time::OffsetDateTime;
-use azure_core::Result;
 use spector_armcommon::models::{ConfidentialResource, ConfidentialResourceProperties};
-use spector_armcommon::CommonPropertiesClient;
-use std::sync::Arc;
-
-#[derive(Debug)]
-struct FakeTokenCredential {
-    pub token: String,
-}
-
-impl FakeTokenCredential {
-    pub fn new(token: String) -> Self {
-        FakeTokenCredential { token }
-    }
-}
-
-#[async_trait::async_trait]
-impl TokenCredential for FakeTokenCredential {
-    async fn get_token(
-        &self,
-        _scopes: &[&str],
-        _options: Option<TokenRequestOptions<'_>>,
-    ) -> Result<AccessToken> {
-        Ok(AccessToken::new(
-            self.token.clone(),
-            OffsetDateTime::now_utc(),
-        ))
-    }
-}
-
-fn create_client() -> CommonPropertiesClient {
-    CommonPropertiesClient::new(
-        "http://localhost:3000",
-        Arc::new(FakeTokenCredential::new("fake_token".to_string())),
-        "00000000-0000-0000-0000-000000000000".to_string(),
-        None,
-    )
-    .unwrap()
-}
 
 #[tokio::test]
 async fn create_for_user_defined_error() {
@@ -56,7 +18,7 @@ async fn create_for_user_defined_error() {
         ..Default::default()
     };
 
-    let client = create_client();
+    let client = common::create_client();
     let rsp = client
         .get_common_properties_error_client()
         .create_for_user_defined_error("test-rg", "resource", resource.try_into().unwrap(), None)
@@ -67,7 +29,7 @@ async fn create_for_user_defined_error() {
 
 #[tokio::test]
 async fn get_for_predefined_error() {
-    let client = create_client();
+    let client = common::create_client();
     let rsp = client
         .get_common_properties_error_client()
         .get_for_predefined_error("test-rg", "resource", None)
diff --git a/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_managed_identity_client_test.rs b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_managed_identity_client_test.rs
index 53a8c07fb..267a09afd 100644
--- a/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_managed_identity_client_test.rs
+++ b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_managed_identity_client_test.rs
@@ -2,51 +2,13 @@
 //
 // Licensed under the MIT License. See License.txt in the project root for license information.
 
-use azure_core::credentials::{AccessToken, TokenCredential, TokenRequestOptions};
-use azure_core::time::OffsetDateTime;
-use azure_core::Result;
+mod common;
+
 use spector_armcommon::models::{
     ManagedIdentityTrackedResource, ManagedIdentityTrackedResourceProperties,
     ManagedServiceIdentity, ManagedServiceIdentityType, UserAssignedIdentity,
 };
-use spector_armcommon::CommonPropertiesClient;
 use std::collections::HashMap;
-use std::sync::Arc;
-
-#[derive(Debug)]
-struct FakeTokenCredential {
-    pub token: String,
-}
-
-impl FakeTokenCredential {
-    pub fn new(token: String) -> Self {
-        FakeTokenCredential { token }
-    }
-}
-
-#[async_trait::async_trait]
-impl TokenCredential for FakeTokenCredential {
-    async fn get_token(
-        &self,
-        _scopes: &[&str],
-        _options: Option<TokenRequestOptions<'_>>,
-    ) -> Result<AccessToken> {
-        Ok(AccessToken::new(
-            self.token.clone(),
-            OffsetDateTime::now_utc(),
-        ))
-    }
-}
-
-fn create_client() -> CommonPropertiesClient {
-    CommonPropertiesClient::new(
-        "http://localhost:3000",
-        Arc::new(FakeTokenCredential::new("fake_token".to_string())),
-        "00000000-0000-0000-0000-000000000000".to_string(),
-        None,
-    )
-    .unwrap()
-}
 
 fn get_valid_mi_resource() -> ManagedIdentityTrackedResource {
     ManagedIdentityTrackedResource {
@@ -55,7 +17,7 @@ fn get_valid_mi_resource() -> ManagedIdentityTrackedResource {
             principal_id: Some("00000000-0000-0000-0000-000000000000".to_string()),
             tenant_id: Some("00000000-0000-0000-0000-000000000000".to_string()),
             type_prop:
-                Some(spector_armcommon::models::ManagedServiceIdentityType::SystemAssigned),
+                Some(ManagedServiceIdentityType::SystemAssigned),
             ..Default::default()
         }),
         location: Some("eastus".to_string()),
@@ -74,14 +36,14 @@ fn get_valid_mi_resource() -> ManagedIdentityTrackedResource {
 async fn create_with_system_assigned() {
     let resource = ManagedIdentityTrackedResource {
         identity: Some(ManagedServiceIdentity {
-            type_prop: Some(spector_armcommon::models::ManagedServiceIdentityType::SystemAssigned),
+            type_prop: Some(ManagedServiceIdentityType::SystemAssigned),
             ..Default::default()
         }),
         location: Some("eastus".to_string()),
         ..Default::default()
     };
 
-    let client = create_client();
+    let client = common::create_client();
     let resp = client
         .get_common_properties_managed_identity_client()
         .create_with_system_assigned("test-rg", "identity", resource.try_into().unwrap(), None)
@@ -111,7 +73,7 @@ async fn create_with_system_assigned() {
 
 #[tokio::test]
 async fn get() {
-    let client = create_client();
+    let client = common::create_client();
     let resp = client
         .get_common_properties_managed_identity_client()
         .get("test-rg", "identity", None)
@@ -153,7 +115,7 @@ async fn update_with_user_assigned_and_system_assigned() {
             ..Default::default()
     };
 
-    let client = create_client();
+    let client = common::create_client();
     let resp = client
         .get_common_properties_managed_identity_client()
         .update_with_user_assigned_and_system_assigned(

From f0ccaf9a3137b4f43a93dd5cbd3f690d477a7204 Mon Sep 17 00:00:00 2001
From: Anton Kolesnyk <antkmsft@users.noreply.github.com>
Date: Fri, 13 Feb 2026 01:47:21 -0800
Subject: [PATCH 08/16] Verify error messages in the test

---
 .../common_properties_error_client_test.rs    | 31 +++++++++++--------
 1 file changed, 18 insertions(+), 13 deletions(-)

diff --git a/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs
index 8f6379e1c..9d192ce3d 100644
--- a/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs
+++ b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs
@@ -5,14 +5,28 @@
 mod common;
 
 use azure_core::http::StatusCode;
+use azure_core::Error;
 use spector_armcommon::models::{ConfidentialResource, ConfidentialResourceProperties};
 
+#[tokio::test]
+async fn get_for_predefined_error() {
+    let client = common::create_client();
+    let rsp = client
+        .get_common_properties_error_client()
+        .get_for_predefined_error("test-rg", "resource", None)
+        .await;
+
+    let err = rsp.unwrap_err();
+    assert_eq!(err.http_status(), Some(StatusCode::NotFound));
+    assert_eq!(err.to_string(), "The Resource 'Azure.ResourceManager.CommonProperties/confidentialResources/confidential' under resource group 'test-rg' was not found.");
+}
+
 #[tokio::test]
 async fn create_for_user_defined_error() {
     let resource = ConfidentialResource {
         location: Some("eastus".to_string()),
         properties: Some(ConfidentialResourceProperties {
-            username: Some("testuser".to_string()),
+            username: Some("00".to_string()),
             ..Default::default()
         }),
         ..Default::default()
@@ -24,16 +38,7 @@ async fn create_for_user_defined_error() {
         .create_for_user_defined_error("test-rg", "resource", resource.try_into().unwrap(), None)
         .await;
 
-    assert_eq!(rsp.unwrap_err().http_status(), Some(StatusCode::BadRequest));
-}
-
-#[tokio::test]
-async fn get_for_predefined_error() {
-    let client = common::create_client();
-    let rsp = client
-        .get_common_properties_error_client()
-        .get_for_predefined_error("test-rg", "resource", None)
-        .await;
-
-    assert_eq!(rsp.unwrap_err().http_status(), Some(StatusCode::NotFound));
+    let err = rsp.unwrap_err();
+    assert_eq!(err.http_status(), Some(StatusCode::BadRequest));
+    assert_eq!(err.to_string(), "Username should not contain only numbers.");
 }

From c34b69861a605ee13cb408fa694f104bb30185b9 Mon Sep 17 00:00:00 2001
From: Anton Kolesnyk <antkmsft@users.noreply.github.com>
Date: Fri, 13 Feb 2026 13:27:53 -0800
Subject: [PATCH 09/16] Clippy

---
 packages/typespec-rust/src/tcgcadapter/adapter.ts          | 7 ++++++-
 .../tests/common_properties_error_client_test.rs           | 1 -
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/packages/typespec-rust/src/tcgcadapter/adapter.ts b/packages/typespec-rust/src/tcgcadapter/adapter.ts
index 2618e9585..85e6469f7 100644
--- a/packages/typespec-rust/src/tcgcadapter/adapter.ts
+++ b/packages/typespec-rust/src/tcgcadapter/adapter.ts
@@ -173,7 +173,12 @@ export class Adapter {
     const processedTypes = new Set<string>();
 
     for (const model of this.ctx.sdkPackage.models) {
-      if ((model.usage & tcgc.UsageFlags.Input) === 0 && (model.usage & tcgc.UsageFlags.Output) === 0 && (model.usage & tcgc.UsageFlags.Spread) === 0) {
+      if (
+           (model.usage & tcgc.UsageFlags.Input) === 0
+        && (model.usage & tcgc.UsageFlags.Output) === 0
+        && (model.usage & tcgc.UsageFlags.Spread) === 0
+        && (model.usage & tcgc.UsageFlags.Exception) === 0
+      ) {
         // skip types without input and output usage. this will include core
         // types unless they're explicitly referenced (e.g. a model property).
         // we keep the models for spread params as we internally use them.
diff --git a/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs
index 9d192ce3d..2f731a16b 100644
--- a/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs
+++ b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs
@@ -5,7 +5,6 @@
 mod common;
 
 use azure_core::http::StatusCode;
-use azure_core::Error;
 use spector_armcommon::models::{ConfidentialResource, ConfidentialResourceProperties};
 
 #[tokio::test]

From da3c2ae456e8bab4837a2adaff547ab0572031bd Mon Sep 17 00:00:00 2001
From: Anton Kolesnyk <antkmsft@users.noreply.github.com>
Date: Tue, 17 Feb 2026 08:00:13 -0800
Subject: [PATCH 10/16] Remove unintended change

---
 packages/typespec-rust/src/tcgcadapter/adapter.ts | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/packages/typespec-rust/src/tcgcadapter/adapter.ts b/packages/typespec-rust/src/tcgcadapter/adapter.ts
index 85e6469f7..2618e9585 100644
--- a/packages/typespec-rust/src/tcgcadapter/adapter.ts
+++ b/packages/typespec-rust/src/tcgcadapter/adapter.ts
@@ -173,12 +173,7 @@ export class Adapter {
     const processedTypes = new Set<string>();
 
     for (const model of this.ctx.sdkPackage.models) {
-      if (
-           (model.usage & tcgc.UsageFlags.Input) === 0
-        && (model.usage & tcgc.UsageFlags.Output) === 0
-        && (model.usage & tcgc.UsageFlags.Spread) === 0
-        && (model.usage & tcgc.UsageFlags.Exception) === 0
-      ) {
+      if ((model.usage & tcgc.UsageFlags.Input) === 0 && (model.usage & tcgc.UsageFlags.Output) === 0 && (model.usage & tcgc.UsageFlags.Spread) === 0) {
         // skip types without input and output usage. this will include core
         // types unless they're explicitly referenced (e.g. a model property).
         // we keep the models for spread params as we internally use them.

From a805effc969319036a201ba5ae606f3b59f5fad7 Mon Sep 17 00:00:00 2001
From: Anton Kolesnyk <41349689+antkmsft@users.noreply.github.com>
Date: Mon, 23 Feb 2026 13:14:58 -0800
Subject: [PATCH 11/16] Do not report the user-defined error test, until we
 finalize on how to better implement it

---
 .../tests/common_properties_error_client_test.rs                 | 1 +
 1 file changed, 1 insertion(+)

diff --git a/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs
index 2f731a16b..228029cbb 100644
--- a/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs
+++ b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs
@@ -21,6 +21,7 @@ async fn get_for_predefined_error() {
 }
 
 #[tokio::test]
+#[ignore] // Follow up on custom error design
 async fn create_for_user_defined_error() {
     let resource = ConfidentialResource {
         location: Some("eastus".to_string()),

From 6fad6155d1de454b15d37ccfafd7255bca646dbc Mon Sep 17 00:00:00 2001
From: Anton Kolesnyk <antkmsft@users.noreply.github.com>
Date: Wed, 25 Feb 2026 11:40:10 -0800
Subject: [PATCH 12/16] TryFrom

---
 packages/typespec-rust/.scripts/tspcompile.js |   6 +
 packages/typespec-rust/src/codegen/context.ts |  27 ++++
 packages/typespec-rust/src/codegen/models.ts  |   7 +
 packages/typespec-rust/src/codemodel/types.ts |   3 +
 packages/typespec-rust/src/lib.ts             |   8 ++
 .../typespec-rust/src/tcgcadapter/adapter.ts  |   9 +-
 packages/typespec-rust/test/Cargo.lock        |   1 +
 .../common-properties/Cargo.toml              |   1 +
 .../src/generated/models/models.rs            | 108 +++++++++++++-
 .../src/generated/models/models_impl.rs       | 133 +++++++++++++++++-
 .../common_properties_error_client_test.rs    |  20 ++-
 .../common-properties/tspconfig.yaml          |   3 +
 12 files changed, 320 insertions(+), 6 deletions(-)
 create mode 100644 packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tspconfig.yaml

diff --git a/packages/typespec-rust/.scripts/tspcompile.js b/packages/typespec-rust/.scripts/tspcompile.js
index a075659a4..85467c9cb 100644
--- a/packages/typespec-rust/.scripts/tspcompile.js
+++ b/packages/typespec-rust/.scripts/tspcompile.js
@@ -218,6 +218,12 @@ function generate(crate, input, outputDir, additionalArgs) {
       additionalArgs[i] = `--option="@azure-tools/typespec-rust.${additionalArgs[i]}"`;
     }
   }
+
+  const tspConfigPath = `${outputDir}/tspconfig.yaml`;
+  if (fs.existsSync(tspConfigPath)) {
+    additionalArgs.push(`--config=${tspConfigPath}`);
+  }
+
   sem.take(async function() {
     // if a tsp file isn't specified, first check
     // for a client.tsp file. if that doesn't exist
diff --git a/packages/typespec-rust/src/codegen/context.ts b/packages/typespec-rust/src/codegen/context.ts
index b76fdd0de..a47701590 100644
--- a/packages/typespec-rust/src/codegen/context.ts
+++ b/packages/typespec-rust/src/codegen/context.ts
@@ -131,6 +131,33 @@ export class Context {
     return content;
   }
 
+  /**
+   * returns the impl azure_core::Error for the error type.
+   * if no impl is required, the empty string is returned.
+   *
+   * @param model the model for which to implement TryFrom
+   * @param use the use statement builder currently in scope
+   * @returns the impl TryFrom<T> block for type or the empty string
+   */
+  getTryFromForError(model: rust.Model, use: Use): string {
+    if ((model.flags & rust.ModelFlags.Error) !== rust.ModelFlags.Error) {
+      return '';
+    }
+
+    use.add('azure_core::error', 'ErrorKind');
+    const indent = new helpers.indentation();
+    let content = `impl TryFrom<azure_core::Error> for ${helpers.getTypeDeclaration(model)} {\n`;
+    content += `${indent.get()}type Error = azure_core::Error;\n`;
+    content += `${indent.get()}fn try_from(error: azure_core::Error) -> std::result::Result<Self, Self::Error> {\n`;
+    content += `${indent.push().get()}match error.kind() {`
+    content += `${indent.push().get()}ErrorKind::HttpResponse { raw_response: Some(raw_response), .. } => Ok(serde_json::from_str(raw_response.body().clone().into_string()?.as_ref())?),`;
+    content += `${indent.get()}_ => Err(azure_core::Error::with_message(azure_core::error::ErrorKind::DataConversion, "ErrorKind was not HttpResponse and could not be parsed."))`;
+    content += `${indent.pop().get()}}\n`;
+    content += `${indent.pop().get()}}\n`;
+    content += '}\n\n';
+    return content;
+  }
+
   /**
    * returns the body format for the provided model
    * 
diff --git a/packages/typespec-rust/src/codegen/models.ts b/packages/typespec-rust/src/codegen/models.ts
index b3e5a6df3..991a9c0dc 100644
--- a/packages/typespec-rust/src/codegen/models.ts
+++ b/packages/typespec-rust/src/codegen/models.ts
@@ -232,6 +232,13 @@ function emitModelImpls(crate: rust.Crate, context: Context): helpers.Module | u
       entries.push(forReq);
     }
 
+    const forErr = context.getTryFromForError(model, use);
+    if (forErr) {
+      use.addForType(model);
+      entries.push(forErr);
+    }
+
+
     const pageImpl = context.getPageImplForType(model, use);
     if (pageImpl) {
       use.addForType(model);
diff --git a/packages/typespec-rust/src/codemodel/types.ts b/packages/typespec-rust/src/codemodel/types.ts
index c97b66aa6..17d15e7ee 100644
--- a/packages/typespec-rust/src/codemodel/types.ts
+++ b/packages/typespec-rust/src/codemodel/types.ts
@@ -325,6 +325,9 @@ export enum ModelFlags {
 
   /** model is used as output from a method */
   Output = 2,
+
+  /** model is as error */
+  Error = 4,
 }
 
 /** DateTimeEncoding is the wire format of the date/time */
diff --git a/packages/typespec-rust/src/lib.ts b/packages/typespec-rust/src/lib.ts
index 097c57a18..969e157b8 100644
--- a/packages/typespec-rust/src/lib.ts
+++ b/packages/typespec-rust/src/lib.ts
@@ -19,6 +19,8 @@ export interface RustEmitterOptions {
   'overwrite-lib-rs': boolean;
   /** Whether to omit documentation links in generated code. Defaults to false */
   'temp-omit-doc-links': boolean;
+  /** Whether to emit error types */
+  'emit-error-types': boolean;
 }
 
 const EmitterOptionsSchema: JSONSchemaType<RustEmitterOptions> = {
@@ -59,6 +61,12 @@ const EmitterOptionsSchema: JSONSchemaType<RustEmitterOptions> = {
       default: false,
       description: 'Whether to omit documentation links in generated code. Defaults to false'
     },
+    'emit-error-types': {
+      type: 'boolean',
+      nullable: false,
+      default: false,
+      description: 'Whether to emit error types. Defaults to false'
+    },
   },
   required: [
     'crate-name',
diff --git a/packages/typespec-rust/src/tcgcadapter/adapter.ts b/packages/typespec-rust/src/tcgcadapter/adapter.ts
index 2618e9585..5b2df8e56 100644
--- a/packages/typespec-rust/src/tcgcadapter/adapter.ts
+++ b/packages/typespec-rust/src/tcgcadapter/adapter.ts
@@ -173,7 +173,11 @@ export class Adapter {
     const processedTypes = new Set<string>();
 
     for (const model of this.ctx.sdkPackage.models) {
-      if ((model.usage & tcgc.UsageFlags.Input) === 0 && (model.usage & tcgc.UsageFlags.Output) === 0 && (model.usage & tcgc.UsageFlags.Spread) === 0) {
+      let usageFlags = tcgc.UsageFlags.Input | tcgc.UsageFlags.Output | tcgc.UsageFlags.Spread;
+      if (this.options['emit-error-types']) {
+        usageFlags |= tcgc.UsageFlags.Exception;
+      }
+      if ((model.usage & usageFlags) === 0) {
         // skip types without input and output usage. this will include core
         // types unless they're explicitly referenced (e.g. a model property).
         // we keep the models for spread params as we internally use them.
@@ -358,6 +362,9 @@ export class Adapter {
     if (<tcgc.UsageFlags>(model.usage & tcgc.UsageFlags.Output) === tcgc.UsageFlags.Output) {
       modelFlags |= rust.ModelFlags.Output;
     }
+    if (this.options['emit-error-types'] && <tcgc.UsageFlags>(model.usage & tcgc.UsageFlags.Exception) === tcgc.UsageFlags.Exception) {
+      modelFlags |= rust.ModelFlags.Error;
+    }
 
     rustModel = new rust.Model(modelName, model.access === 'internal' ? 'pubCrate' : 'pub', modelFlags);
     rustModel.docs = this.adaptDocs(model.summary, model.doc);
diff --git a/packages/typespec-rust/test/Cargo.lock b/packages/typespec-rust/test/Cargo.lock
index cd2fe6186..4a7ca4fc4 100644
--- a/packages/typespec-rust/test/Cargo.lock
+++ b/packages/typespec-rust/test/Cargo.lock
@@ -1511,6 +1511,7 @@ dependencies = [
  "async-trait",
  "azure_core",
  "serde",
+ "serde_json",
  "tokio",
 ]
 
diff --git a/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/Cargo.toml b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/Cargo.toml
index 32d3ba2c2..9967a1d72 100644
--- a/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/Cargo.toml
+++ b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/Cargo.toml
@@ -13,6 +13,7 @@ default = ["azure_core/default"]
 [dependencies]
 azure_core = { workspace = true }
 serde = { workspace = true }
+serde_json = { workspace = true }
 
 [dev-dependencies]
 async-trait = { workspace = true }
diff --git a/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/src/generated/models/models.rs b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/src/generated/models/models.rs
index e3d5505da..568ca339d 100644
--- a/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/src/generated/models/models.rs
+++ b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/src/generated/models/models.rs
@@ -4,10 +4,58 @@
 // Code generated by Microsoft (R) Rust Code Generator. DO NOT EDIT.
 
 use super::{CreatedByType, ManagedServiceIdentityType};
-use azure_core::{fmt::SafeDebug, time::OffsetDateTime};
+use azure_core::{fmt::SafeDebug, time::OffsetDateTime, Value};
 use serde::{Deserialize, Serialize};
 use std::collections::HashMap;
 
+/// Api error.
+#[derive(Clone, Default, Deserialize, SafeDebug, Serialize)]
+pub struct ApiError {
+    /// The error code.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub code: Option<String>,
+
+    /// The Api error details
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub details: Option<Vec<ApiErrorBase>>,
+
+    /// The Api inner error
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub innererror: Option<InnerError>,
+
+    /// The error message.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub message: Option<String>,
+
+    /// The target of the particular error.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub target: Option<String>,
+}
+
+/// Api error base.
+#[derive(Clone, Default, Deserialize, SafeDebug, Serialize)]
+pub struct ApiErrorBase {
+    /// The error code.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub code: Option<String>,
+
+    /// The error message.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub message: Option<String>,
+
+    /// The target of the particular error.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub target: Option<String>,
+}
+
+/// An error response.
+#[derive(Clone, Default, Deserialize, SafeDebug, Serialize)]
+pub struct CloudError {
+    /// Api error.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub error: Option<ApiError>,
+}
+
 /// Concrete tracked resource types can be created by aliasing this type using a specific property type.
 #[derive(Clone, Default, Deserialize, SafeDebug, Serialize)]
 pub struct ConfidentialResource {
@@ -51,6 +99,64 @@ pub struct ConfidentialResourceProperties {
     pub username: Option<String>,
 }
 
+/// The resource management error additional info.
+#[derive(Clone, Default, Deserialize, SafeDebug, Serialize)]
+pub struct ErrorAdditionalInfo {
+    /// The additional info.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub info: Option<Value>,
+
+    /// The additional info type.
+    #[serde(rename = "type", skip_serializing_if = "Option::is_none")]
+    pub type_prop: Option<String>,
+}
+
+/// The error detail.
+#[derive(Clone, Default, Deserialize, SafeDebug, Serialize)]
+pub struct ErrorDetail {
+    /// The error additional info.
+    #[serde(rename = "additionalInfo", skip_serializing_if = "Option::is_none")]
+    pub additional_info: Option<Vec<ErrorAdditionalInfo>>,
+
+    /// The error code.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub code: Option<String>,
+
+    /// The error details.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub details: Option<Vec<ErrorDetail>>,
+
+    /// The error message.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub message: Option<String>,
+
+    /// The error target.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub target: Option<String>,
+}
+
+/// Error response
+///
+/// Common error response for all Azure Resource Manager APIs to return error details for failed operations.
+#[derive(Clone, Default, Deserialize, SafeDebug, Serialize)]
+pub struct ErrorResponse {
+    /// The error object.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub error: Option<ErrorDetail>,
+}
+
+/// Inner error details.
+#[derive(Clone, Default, Deserialize, SafeDebug, Serialize)]
+pub struct InnerError {
+    /// The internal error message or exception dump.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub errordetail: Option<String>,
+
+    /// The exception type.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub exceptiontype: Option<String>,
+}
+
 /// Concrete tracked resource types can be created by aliasing this type using a specific property type.
 #[derive(Clone, Default, Deserialize, SafeDebug, Serialize)]
 pub struct ManagedIdentityTrackedResource {
diff --git a/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/src/generated/models/models_impl.rs b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/src/generated/models/models_impl.rs
index a81ef33a5..b1059ada1 100644
--- a/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/src/generated/models/models_impl.rs
+++ b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/src/generated/models/models_impl.rs
@@ -3,8 +3,11 @@
 // Licensed under the MIT License. See License.txt in the project root for license information.
 // Code generated by Microsoft (R) Rust Code Generator. DO NOT EDIT.
 
-use super::{ConfidentialResource, ManagedIdentityTrackedResource};
-use azure_core::{http::RequestContent, json::to_json, Result};
+use super::{
+    ApiError, ApiErrorBase, CloudError, ConfidentialResource, ErrorAdditionalInfo, ErrorDetail,
+    ErrorResponse, InnerError, ManagedIdentityTrackedResource,
+};
+use azure_core::{error::ErrorKind, http::RequestContent, json::to_json, Result};
 
 impl TryFrom<ConfidentialResource> for RequestContent<ConfidentialResource> {
     type Error = azure_core::Error;
@@ -19,3 +22,129 @@ impl TryFrom<ManagedIdentityTrackedResource> for RequestContent<ManagedIdentityT
         Ok(to_json(&value)?.into())
     }
 }
+
+impl TryFrom<azure_core::Error> for ApiError {
+    type Error = azure_core::Error;
+    fn try_from(error: azure_core::Error) -> std::result::Result<Self, Self::Error> {
+        match error.kind() {
+            ErrorKind::HttpResponse {
+                raw_response: Some(raw_response),
+                ..
+            } => Ok(serde_json::from_str(
+                raw_response.body().clone().into_string()?.as_ref(),
+            )?),
+            _ => Err(azure_core::Error::with_message(
+                azure_core::error::ErrorKind::DataConversion,
+                "ErrorKind was not HttpResponse and could not be parsed.",
+            )),
+        }
+    }
+}
+
+impl TryFrom<azure_core::Error> for ApiErrorBase {
+    type Error = azure_core::Error;
+    fn try_from(error: azure_core::Error) -> std::result::Result<Self, Self::Error> {
+        match error.kind() {
+            ErrorKind::HttpResponse {
+                raw_response: Some(raw_response),
+                ..
+            } => Ok(serde_json::from_str(
+                raw_response.body().clone().into_string()?.as_ref(),
+            )?),
+            _ => Err(azure_core::Error::with_message(
+                azure_core::error::ErrorKind::DataConversion,
+                "ErrorKind was not HttpResponse and could not be parsed.",
+            )),
+        }
+    }
+}
+
+impl TryFrom<azure_core::Error> for CloudError {
+    type Error = azure_core::Error;
+    fn try_from(error: azure_core::Error) -> std::result::Result<Self, Self::Error> {
+        match error.kind() {
+            ErrorKind::HttpResponse {
+                raw_response: Some(raw_response),
+                ..
+            } => Ok(serde_json::from_str(
+                raw_response.body().clone().into_string()?.as_ref(),
+            )?),
+            _ => Err(azure_core::Error::with_message(
+                azure_core::error::ErrorKind::DataConversion,
+                "ErrorKind was not HttpResponse and could not be parsed.",
+            )),
+        }
+    }
+}
+
+impl TryFrom<azure_core::Error> for ErrorAdditionalInfo {
+    type Error = azure_core::Error;
+    fn try_from(error: azure_core::Error) -> std::result::Result<Self, Self::Error> {
+        match error.kind() {
+            ErrorKind::HttpResponse {
+                raw_response: Some(raw_response),
+                ..
+            } => Ok(serde_json::from_str(
+                raw_response.body().clone().into_string()?.as_ref(),
+            )?),
+            _ => Err(azure_core::Error::with_message(
+                azure_core::error::ErrorKind::DataConversion,
+                "ErrorKind was not HttpResponse and could not be parsed.",
+            )),
+        }
+    }
+}
+
+impl TryFrom<azure_core::Error> for ErrorDetail {
+    type Error = azure_core::Error;
+    fn try_from(error: azure_core::Error) -> std::result::Result<Self, Self::Error> {
+        match error.kind() {
+            ErrorKind::HttpResponse {
+                raw_response: Some(raw_response),
+                ..
+            } => Ok(serde_json::from_str(
+                raw_response.body().clone().into_string()?.as_ref(),
+            )?),
+            _ => Err(azure_core::Error::with_message(
+                azure_core::error::ErrorKind::DataConversion,
+                "ErrorKind was not HttpResponse and could not be parsed.",
+            )),
+        }
+    }
+}
+
+impl TryFrom<azure_core::Error> for ErrorResponse {
+    type Error = azure_core::Error;
+    fn try_from(error: azure_core::Error) -> std::result::Result<Self, Self::Error> {
+        match error.kind() {
+            ErrorKind::HttpResponse {
+                raw_response: Some(raw_response),
+                ..
+            } => Ok(serde_json::from_str(
+                raw_response.body().clone().into_string()?.as_ref(),
+            )?),
+            _ => Err(azure_core::Error::with_message(
+                azure_core::error::ErrorKind::DataConversion,
+                "ErrorKind was not HttpResponse and could not be parsed.",
+            )),
+        }
+    }
+}
+
+impl TryFrom<azure_core::Error> for InnerError {
+    type Error = azure_core::Error;
+    fn try_from(error: azure_core::Error) -> std::result::Result<Self, Self::Error> {
+        match error.kind() {
+            ErrorKind::HttpResponse {
+                raw_response: Some(raw_response),
+                ..
+            } => Ok(serde_json::from_str(
+                raw_response.body().clone().into_string()?.as_ref(),
+            )?),
+            _ => Err(azure_core::Error::with_message(
+                azure_core::error::ErrorKind::DataConversion,
+                "ErrorKind was not HttpResponse and could not be parsed.",
+            )),
+        }
+    }
+}
diff --git a/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs
index 228029cbb..f8d0c8ef8 100644
--- a/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs
+++ b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tests/common_properties_error_client_test.rs
@@ -5,7 +5,7 @@
 mod common;
 
 use azure_core::http::StatusCode;
-use spector_armcommon::models::{ConfidentialResource, ConfidentialResourceProperties};
+use spector_armcommon::models::{CloudError, ConfidentialResource, ConfidentialResourceProperties};
 
 #[tokio::test]
 async fn get_for_predefined_error() {
@@ -21,7 +21,6 @@ async fn get_for_predefined_error() {
 }
 
 #[tokio::test]
-#[ignore] // Follow up on custom error design
 async fn create_for_user_defined_error() {
     let resource = ConfidentialResource {
         location: Some("eastus".to_string()),
@@ -41,4 +40,21 @@ async fn create_for_user_defined_error() {
     let err = rsp.unwrap_err();
     assert_eq!(err.http_status(), Some(StatusCode::BadRequest));
     assert_eq!(err.to_string(), "Username should not contain only numbers.");
+
+    let cloud_err: CloudError = err.try_into().unwrap();
+
+    let cloud_error = cloud_err.error.as_ref();
+    assert!(cloud_error.is_some());
+    assert_eq!(cloud_error.unwrap().code, Some("BadRequest".to_string()));
+    assert_eq!(
+        cloud_error.unwrap().message,
+        Some("Username should not contain only numbers.".to_string())
+    );
+
+    let cloud_inner = cloud_error.unwrap().innererror.as_ref();
+    assert!(cloud_inner.is_some());
+    assert_eq!(
+        cloud_inner.unwrap().exceptiontype,
+        Some("general".to_string())
+    );
 }
diff --git a/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tspconfig.yaml b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tspconfig.yaml
new file mode 100644
index 000000000..c6df08f53
--- /dev/null
+++ b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/tspconfig.yaml
@@ -0,0 +1,3 @@
+options:
+  "@azure-tools/typespec-rust":
+    emit-error-types: true

From 1bece99c27868eb01bc17733405b006d6ee26fd0 Mon Sep 17 00:00:00 2001
From: Anton Kolesnyk <41349689+antkmsft@users.noreply.github.com>
Date: Wed, 25 Feb 2026 11:51:09 -0800
Subject: [PATCH 13/16] Fix typo in Error enum comment

---
 packages/typespec-rust/src/codemodel/types.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/typespec-rust/src/codemodel/types.ts b/packages/typespec-rust/src/codemodel/types.ts
index 4c931beb5..63137de55 100644
--- a/packages/typespec-rust/src/codemodel/types.ts
+++ b/packages/typespec-rust/src/codemodel/types.ts
@@ -341,7 +341,7 @@ export enum ModelFlags {
   /** model is a sub-type in a polymorphic discriminated union */
   PolymorphicSubtype = 4,
 
-  /** model is as error */
+  /** model is an error */
   Error = 8,
 }
 

From 78633826a0c1c069721af772e3d0a57d9ad40403 Mon Sep 17 00:00:00 2001
From: Anton Kolesnyk <antkmsft@users.noreply.github.com>
Date: Wed, 25 Feb 2026 12:00:50 -0800
Subject: [PATCH 14/16] Commit generated file after merge with latest main

---
 .../common-properties/src/generated/models/models.rs       | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/src/generated/models/models.rs b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/src/generated/models/models.rs
index 50b07d459..a4aaded43 100644
--- a/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/src/generated/models/models.rs
+++ b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/src/generated/models/models.rs
@@ -10,6 +10,7 @@ use std::collections::HashMap;
 
 /// Api error.
 #[derive(Clone, Default, Deserialize, SafeDebug, Serialize)]
+#[non_exhaustive]
 pub struct ApiError {
     /// The error code.
     #[serde(skip_serializing_if = "Option::is_none")]
@@ -34,6 +35,7 @@ pub struct ApiError {
 
 /// Api error base.
 #[derive(Clone, Default, Deserialize, SafeDebug, Serialize)]
+#[non_exhaustive]
 pub struct ApiErrorBase {
     /// The error code.
     #[serde(skip_serializing_if = "Option::is_none")]
@@ -50,6 +52,7 @@ pub struct ApiErrorBase {
 
 /// An error response.
 #[derive(Clone, Default, Deserialize, SafeDebug, Serialize)]
+#[non_exhaustive]
 pub struct CloudError {
     /// Api error.
     #[serde(skip_serializing_if = "Option::is_none")]
@@ -101,6 +104,7 @@ pub struct ConfidentialResourceProperties {
 
 /// The resource management error additional info.
 #[derive(Clone, Default, Deserialize, SafeDebug, Serialize)]
+#[non_exhaustive]
 pub struct ErrorAdditionalInfo {
     /// The additional info.
     #[serde(skip_serializing_if = "Option::is_none")]
@@ -113,6 +117,7 @@ pub struct ErrorAdditionalInfo {
 
 /// The error detail.
 #[derive(Clone, Default, Deserialize, SafeDebug, Serialize)]
+#[non_exhaustive]
 pub struct ErrorDetail {
     /// The error additional info.
     #[serde(rename = "additionalInfo", skip_serializing_if = "Option::is_none")]
@@ -139,6 +144,7 @@ pub struct ErrorDetail {
 ///
 /// Common error response for all Azure Resource Manager APIs to return error details for failed operations.
 #[derive(Clone, Default, Deserialize, SafeDebug, Serialize)]
+#[non_exhaustive]
 pub struct ErrorResponse {
     /// The error object.
     #[serde(skip_serializing_if = "Option::is_none")]
@@ -147,6 +153,7 @@ pub struct ErrorResponse {
 
 /// Inner error details.
 #[derive(Clone, Default, Deserialize, SafeDebug, Serialize)]
+#[non_exhaustive]
 pub struct InnerError {
     /// The internal error message or exception dump.
     #[serde(skip_serializing_if = "Option::is_none")]

From 5195c9bfeda9a6e7eb552ec0227a863717fd3eda Mon Sep 17 00:00:00 2001
From: Anton Kolesnyk <antkmsft@users.noreply.github.com>
Date: Wed, 25 Feb 2026 13:01:23 -0800
Subject: [PATCH 15/16] Fix typescript lint

---
 packages/typespec-rust/src/codegen/context.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/typespec-rust/src/codegen/context.ts b/packages/typespec-rust/src/codegen/context.ts
index 2d084fcba..0f49b2219 100644
--- a/packages/typespec-rust/src/codegen/context.ts
+++ b/packages/typespec-rust/src/codegen/context.ts
@@ -140,7 +140,7 @@ export class Context {
    * @returns the impl TryFrom<T> block for type or the empty string
    */
   getTryFromForError(model: rust.Model, use: Use): string {
-    if ((model.flags & rust.ModelFlags.Error) !== rust.ModelFlags.Error) {
+    if ((model.flags & rust.ModelFlags.Error) === 0) {
       return '';
     }
 

From 9ae8aa3be14728b800fb2bbcceb3ded054d5bae3 Mon Sep 17 00:00:00 2001
From: Anton Kolesnyk <antkmsft@users.noreply.github.com>
Date: Wed, 25 Feb 2026 16:32:24 -0800
Subject: [PATCH 16/16] Only generate TryFrom for the error that actually gets
 returned, not all sub-models recursively

---
 .../typespec-rust/src/tcgcadapter/adapter.ts  | 31 +++++-
 .../src/generated/models/models.rs            | 17 +---
 .../src/generated/models/models_impl.rs       | 95 +------------------
 3 files changed, 33 insertions(+), 110 deletions(-)

diff --git a/packages/typespec-rust/src/tcgcadapter/adapter.ts b/packages/typespec-rust/src/tcgcadapter/adapter.ts
index 27133f93f..2352b8e13 100644
--- a/packages/typespec-rust/src/tcgcadapter/adapter.ts
+++ b/packages/typespec-rust/src/tcgcadapter/adapter.ts
@@ -180,6 +180,30 @@ export class Adapter {
 
     const processedTypes = new Set<string>();
 
+    const getErrorModelNames = function(clients: tcgc.SdkClientType<tcgc.SdkHttpOperation>[], visitedClientNames = new Set<string>()) : Set<string> {
+      const errorModelNames = new Set<string>();
+      for (const client of clients) {
+        if (visitedClientNames.has(client.name)) {
+          continue;
+        }
+        visitedClientNames.add(client.name);
+        for (const errorModelName
+          of client.methods.flatMap(mt => mt.operation.exceptions).filter(
+            e => e.type?.kind === 'model').map(md => (md.type as tcgc.SdkModelType).name)
+        ) {
+          errorModelNames.add(errorModelName);
+        }
+
+        for (const errorModelName of getErrorModelNames(client.children ?? [], visitedClientNames).values()) {
+          errorModelNames.add(errorModelName);
+        }
+      }
+
+      return errorModelNames;
+    }
+
+    const errorModelNames = getErrorModelNames(this.ctx.sdkPackage.clients);
+
     for (const model of this.ctx.sdkPackage.models) {
       let usageFlags = tcgc.UsageFlags.Input | tcgc.UsageFlags.Output | tcgc.UsageFlags.Spread;
       if (this.options['emit-error-types']) {
@@ -214,6 +238,9 @@ export class Adapter {
         this.getExternalType(model.external);
       } else {
         const rustModel = this.getModel(model);
+        if ((model.usage & tcgc.UsageFlags.Exception) !== 0 && errorModelNames.has(model.name)) {
+          rustModel.flags |= rust.ModelFlags.Error;
+        }
         this.crate.models.push(rustModel);
       }
     }
@@ -376,14 +403,10 @@ export class Adapter {
     // include error and LRO polling types as output types
     if (
       <tcgc.UsageFlags>(model.usage & tcgc.UsageFlags.Output) === tcgc.UsageFlags.Output ||
-      <tcgc.UsageFlags>(model.usage & tcgc.UsageFlags.Exception) === tcgc.UsageFlags.Exception ||
       <tcgc.UsageFlags>(model.usage & tcgc.UsageFlags.LroPolling) === tcgc.UsageFlags.LroPolling
     ) {
       modelFlags |= rust.ModelFlags.Output;
     }
-    if (this.options['emit-error-types'] && <tcgc.UsageFlags>(model.usage & tcgc.UsageFlags.Exception) === tcgc.UsageFlags.Exception) {
-      modelFlags |= rust.ModelFlags.Error;
-    }
 
     rustModel = new rust.Model(modelName, model.access === 'internal' ? 'pubCrate' : 'pub', modelFlags);
     rustModel.docs = this.adaptDocs(model.summary, model.doc);
diff --git a/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/src/generated/models/models.rs b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/src/generated/models/models.rs
index a4aaded43..69b76a73b 100644
--- a/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/src/generated/models/models.rs
+++ b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/src/generated/models/models.rs
@@ -9,8 +9,7 @@ use serde::{Deserialize, Serialize};
 use std::collections::HashMap;
 
 /// Api error.
-#[derive(Clone, Default, Deserialize, SafeDebug, Serialize)]
-#[non_exhaustive]
+#[derive(Clone, Deserialize, SafeDebug, Serialize)]
 pub struct ApiError {
     /// The error code.
     #[serde(skip_serializing_if = "Option::is_none")]
@@ -34,8 +33,7 @@ pub struct ApiError {
 }
 
 /// Api error base.
-#[derive(Clone, Default, Deserialize, SafeDebug, Serialize)]
-#[non_exhaustive]
+#[derive(Clone, Deserialize, SafeDebug, Serialize)]
 pub struct ApiErrorBase {
     /// The error code.
     #[serde(skip_serializing_if = "Option::is_none")]
@@ -52,7 +50,6 @@ pub struct ApiErrorBase {
 
 /// An error response.
 #[derive(Clone, Default, Deserialize, SafeDebug, Serialize)]
-#[non_exhaustive]
 pub struct CloudError {
     /// Api error.
     #[serde(skip_serializing_if = "Option::is_none")]
@@ -103,8 +100,7 @@ pub struct ConfidentialResourceProperties {
 }
 
 /// The resource management error additional info.
-#[derive(Clone, Default, Deserialize, SafeDebug, Serialize)]
-#[non_exhaustive]
+#[derive(Clone, Deserialize, SafeDebug, Serialize)]
 pub struct ErrorAdditionalInfo {
     /// The additional info.
     #[serde(skip_serializing_if = "Option::is_none")]
@@ -116,8 +112,7 @@ pub struct ErrorAdditionalInfo {
 }
 
 /// The error detail.
-#[derive(Clone, Default, Deserialize, SafeDebug, Serialize)]
-#[non_exhaustive]
+#[derive(Clone, Deserialize, SafeDebug, Serialize)]
 pub struct ErrorDetail {
     /// The error additional info.
     #[serde(rename = "additionalInfo", skip_serializing_if = "Option::is_none")]
@@ -144,7 +139,6 @@ pub struct ErrorDetail {
 ///
 /// Common error response for all Azure Resource Manager APIs to return error details for failed operations.
 #[derive(Clone, Default, Deserialize, SafeDebug, Serialize)]
-#[non_exhaustive]
 pub struct ErrorResponse {
     /// The error object.
     #[serde(skip_serializing_if = "Option::is_none")]
@@ -152,8 +146,7 @@ pub struct ErrorResponse {
 }
 
 /// Inner error details.
-#[derive(Clone, Default, Deserialize, SafeDebug, Serialize)]
-#[non_exhaustive]
+#[derive(Clone, Deserialize, SafeDebug, Serialize)]
 pub struct InnerError {
     /// The internal error message or exception dump.
     #[serde(skip_serializing_if = "Option::is_none")]
diff --git a/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/src/generated/models/models_impl.rs b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/src/generated/models/models_impl.rs
index 9e176a0d6..920ca03f1 100644
--- a/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/src/generated/models/models_impl.rs
+++ b/packages/typespec-rust/test/spector/azure/resource-manager/common-properties/src/generated/models/models_impl.rs
@@ -3,10 +3,7 @@
 //
 // Code generated by Microsoft (R) Rust Code Generator. DO NOT EDIT.
 
-use super::{
-    ApiError, ApiErrorBase, CloudError, ConfidentialResource, ErrorAdditionalInfo, ErrorDetail,
-    ErrorResponse, InnerError, ManagedIdentityTrackedResource,
-};
+use super::{CloudError, ConfidentialResource, ErrorResponse, ManagedIdentityTrackedResource};
 use azure_core::{error::ErrorKind, http::RequestContent, json::to_json, Result};
 
 impl TryFrom<ConfidentialResource> for RequestContent<ConfidentialResource> {
@@ -23,42 +20,6 @@ impl TryFrom<ManagedIdentityTrackedResource> for RequestContent<ManagedIdentityT
     }
 }
 
-impl TryFrom<azure_core::Error> for ApiError {
-    type Error = azure_core::Error;
-    fn try_from(error: azure_core::Error) -> std::result::Result<Self, Self::Error> {
-        match error.kind() {
-            ErrorKind::HttpResponse {
-                raw_response: Some(raw_response),
-                ..
-            } => Ok(serde_json::from_str(
-                raw_response.body().clone().into_string()?.as_ref(),
-            )?),
-            _ => Err(azure_core::Error::with_message(
-                azure_core::error::ErrorKind::DataConversion,
-                "ErrorKind was not HttpResponse and could not be parsed.",
-            )),
-        }
-    }
-}
-
-impl TryFrom<azure_core::Error> for ApiErrorBase {
-    type Error = azure_core::Error;
-    fn try_from(error: azure_core::Error) -> std::result::Result<Self, Self::Error> {
-        match error.kind() {
-            ErrorKind::HttpResponse {
-                raw_response: Some(raw_response),
-                ..
-            } => Ok(serde_json::from_str(
-                raw_response.body().clone().into_string()?.as_ref(),
-            )?),
-            _ => Err(azure_core::Error::with_message(
-                azure_core::error::ErrorKind::DataConversion,
-                "ErrorKind was not HttpResponse and could not be parsed.",
-            )),
-        }
-    }
-}
-
 impl TryFrom<azure_core::Error> for CloudError {
     type Error = azure_core::Error;
     fn try_from(error: azure_core::Error) -> std::result::Result<Self, Self::Error> {
@@ -77,42 +38,6 @@ impl TryFrom<azure_core::Error> for CloudError {
     }
 }
 
-impl TryFrom<azure_core::Error> for ErrorAdditionalInfo {
-    type Error = azure_core::Error;
-    fn try_from(error: azure_core::Error) -> std::result::Result<Self, Self::Error> {
-        match error.kind() {
-            ErrorKind::HttpResponse {
-                raw_response: Some(raw_response),
-                ..
-            } => Ok(serde_json::from_str(
-                raw_response.body().clone().into_string()?.as_ref(),
-            )?),
-            _ => Err(azure_core::Error::with_message(
-                azure_core::error::ErrorKind::DataConversion,
-                "ErrorKind was not HttpResponse and could not be parsed.",
-            )),
-        }
-    }
-}
-
-impl TryFrom<azure_core::Error> for ErrorDetail {
-    type Error = azure_core::Error;
-    fn try_from(error: azure_core::Error) -> std::result::Result<Self, Self::Error> {
-        match error.kind() {
-            ErrorKind::HttpResponse {
-                raw_response: Some(raw_response),
-                ..
-            } => Ok(serde_json::from_str(
-                raw_response.body().clone().into_string()?.as_ref(),
-            )?),
-            _ => Err(azure_core::Error::with_message(
-                azure_core::error::ErrorKind::DataConversion,
-                "ErrorKind was not HttpResponse and could not be parsed.",
-            )),
-        }
-    }
-}
-
 impl TryFrom<azure_core::Error> for ErrorResponse {
     type Error = azure_core::Error;
     fn try_from(error: azure_core::Error) -> std::result::Result<Self, Self::Error> {
@@ -130,21 +55,3 @@ impl TryFrom<azure_core::Error> for ErrorResponse {
         }
     }
 }
-
-impl TryFrom<azure_core::Error> for InnerError {
-    type Error = azure_core::Error;
-    fn try_from(error: azure_core::Error) -> std::result::Result<Self, Self::Error> {
-        match error.kind() {
-            ErrorKind::HttpResponse {
-                raw_response: Some(raw_response),
-                ..
-            } => Ok(serde_json::from_str(
-                raw_response.body().clone().into_string()?.as_ref(),
-            )?),
-            _ => Err(azure_core::Error::with_message(
-                azure_core::error::ErrorKind::DataConversion,
-                "ErrorKind was not HttpResponse and could not be parsed.",
-            )),
-        }
-    }
-}