diff --git a/packages/http-client-csharp/generator/TestProjects/Spector/http/payload/content-negotiation/tspCodeModel.json b/packages/http-client-csharp/generator/TestProjects/Spector/http/payload/content-negotiation/tspCodeModel.json
index 449693b81d4..7fbd3aebb6f 100644
--- a/packages/http-client-csharp/generator/TestProjects/Spector/http/payload/content-negotiation/tspCodeModel.json
+++ b/packages/http-client-csharp/generator/TestProjects/Spector/http/payload/content-negotiation/tspCodeModel.json
@@ -22,7 +22,7 @@
     {
       "$id": "3",
       "kind": "constant",
-      "name": "PngImageContentType",
+      "name": "GetAvatarAsPngRequestAccept",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -38,7 +38,7 @@
     {
       "$id": "5",
       "kind": "constant",
-      "name": "PngImageContentType1",
+      "name": "GetAvatarAsPngRequestAccept1",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -54,7 +54,7 @@
     {
       "$id": "7",
       "kind": "constant",
-      "name": "PngImageContentType2",
+      "name": "GetAvatarAsPngRequestAccept2",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -70,7 +70,7 @@
     {
       "$id": "9",
       "kind": "constant",
-      "name": "JpegImageContentType",
+      "name": "GetAvatarAsJpegRequestAccept",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -86,7 +86,7 @@
     {
       "$id": "11",
       "kind": "constant",
-      "name": "JpegImageContentType1",
+      "name": "GetAvatarAsJpegRequestAccept1",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -102,7 +102,7 @@
     {
       "$id": "13",
       "kind": "constant",
-      "name": "JpegImageContentType2",
+      "name": "GetAvatarAsJpegRequestAccept2",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -118,7 +118,7 @@
     {
       "$id": "15",
       "kind": "constant",
-      "name": "PngImageContentType3",
+      "name": "GetAvatarAsPngRequestAccept3",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -134,7 +134,7 @@
     {
       "$id": "17",
       "kind": "constant",
-      "name": "PngImageContentType4",
+      "name": "GetAvatarAsPngRequestAccept4",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -150,7 +150,7 @@
     {
       "$id": "19",
       "kind": "constant",
-      "name": "PngImageContentType5",
+      "name": "GetAvatarAsPngRequestAccept5",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -166,7 +166,7 @@
     {
       "$id": "21",
       "kind": "constant",
-      "name": "PngImageAsJsonContentType1",
+      "name": "GetAvatarAsJsonRequestAccept",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -182,7 +182,7 @@
     {
       "$id": "23",
       "kind": "constant",
-      "name": "PngImageAsJsonContentType2",
+      "name": "GetAvatarAsJsonRequestAccept1",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -198,7 +198,7 @@
     {
       "$id": "25",
       "kind": "constant",
-      "name": "PngImageAsJsonContentType3",
+      "name": "GetAvatarAsJsonRequestAccept2",
       "namespace": "",
       "usage": "None",
       "valueType": {
diff --git a/packages/http-client-csharp/generator/TestProjects/Spector/http/payload/xml/tspCodeModel.json b/packages/http-client-csharp/generator/TestProjects/Spector/http/payload/xml/tspCodeModel.json
index f3d3730c93e..73f60b20567 100644
--- a/packages/http-client-csharp/generator/TestProjects/Spector/http/payload/xml/tspCodeModel.json
+++ b/packages/http-client-csharp/generator/TestProjects/Spector/http/payload/xml/tspCodeModel.json
@@ -86,7 +86,7 @@
     {
       "$id": "8",
       "kind": "constant",
-      "name": "XmlErrorContentType",
+      "name": "GetResponseContentType",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -102,7 +102,7 @@
     {
       "$id": "10",
       "kind": "constant",
-      "name": "XmlErrorContentType1",
+      "name": "GetResponseContentType1",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -118,7 +118,7 @@
     {
       "$id": "12",
       "kind": "constant",
-      "name": "XmlErrorContentType2",
+      "name": "GetResponseContentType2",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -150,7 +150,7 @@
     {
       "$id": "16",
       "kind": "constant",
-      "name": "XmlErrorContentType3",
+      "name": "GetResponseContentType3",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -166,7 +166,7 @@
     {
       "$id": "18",
       "kind": "constant",
-      "name": "XmlErrorContentType4",
+      "name": "GetResponseContentType4",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -182,7 +182,7 @@
     {
       "$id": "20",
       "kind": "constant",
-      "name": "XmlErrorContentType5",
+      "name": "GetResponseContentType5",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -214,7 +214,7 @@
     {
       "$id": "24",
       "kind": "constant",
-      "name": "XmlErrorContentType6",
+      "name": "GetResponseContentType6",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -230,7 +230,7 @@
     {
       "$id": "26",
       "kind": "constant",
-      "name": "XmlErrorContentType7",
+      "name": "GetResponseContentType7",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -246,7 +246,7 @@
     {
       "$id": "28",
       "kind": "constant",
-      "name": "XmlErrorContentType8",
+      "name": "GetResponseContentType8",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -278,7 +278,7 @@
     {
       "$id": "32",
       "kind": "constant",
-      "name": "XmlErrorContentType9",
+      "name": "GetResponseContentType9",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -294,7 +294,7 @@
     {
       "$id": "34",
       "kind": "constant",
-      "name": "XmlErrorContentType10",
+      "name": "GetResponseContentType10",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -310,7 +310,7 @@
     {
       "$id": "36",
       "kind": "constant",
-      "name": "XmlErrorContentType11",
+      "name": "GetResponseContentType11",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -342,7 +342,7 @@
     {
       "$id": "40",
       "kind": "constant",
-      "name": "XmlErrorContentType12",
+      "name": "GetResponseContentType12",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -358,7 +358,7 @@
     {
       "$id": "42",
       "kind": "constant",
-      "name": "XmlErrorContentType13",
+      "name": "GetResponseContentType13",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -374,7 +374,7 @@
     {
       "$id": "44",
       "kind": "constant",
-      "name": "XmlErrorContentType14",
+      "name": "GetResponseContentType14",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -406,7 +406,7 @@
     {
       "$id": "48",
       "kind": "constant",
-      "name": "XmlErrorContentType15",
+      "name": "GetResponseContentType15",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -422,7 +422,7 @@
     {
       "$id": "50",
       "kind": "constant",
-      "name": "XmlErrorContentType16",
+      "name": "GetResponseContentType16",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -438,7 +438,7 @@
     {
       "$id": "52",
       "kind": "constant",
-      "name": "XmlErrorContentType17",
+      "name": "GetResponseContentType17",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -470,7 +470,7 @@
     {
       "$id": "56",
       "kind": "constant",
-      "name": "XmlErrorContentType18",
+      "name": "GetResponseContentType18",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -486,7 +486,7 @@
     {
       "$id": "58",
       "kind": "constant",
-      "name": "XmlErrorContentType19",
+      "name": "GetResponseContentType19",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -502,7 +502,7 @@
     {
       "$id": "60",
       "kind": "constant",
-      "name": "XmlErrorContentType20",
+      "name": "GetResponseContentType20",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -534,7 +534,7 @@
     {
       "$id": "64",
       "kind": "constant",
-      "name": "XmlErrorContentType21",
+      "name": "GetResponseContentType21",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -550,7 +550,7 @@
     {
       "$id": "66",
       "kind": "constant",
-      "name": "XmlErrorContentType22",
+      "name": "GetResponseContentType22",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -566,7 +566,7 @@
     {
       "$id": "68",
       "kind": "constant",
-      "name": "XmlErrorContentType23",
+      "name": "GetResponseContentType23",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -598,7 +598,7 @@
     {
       "$id": "72",
       "kind": "constant",
-      "name": "XmlErrorContentType24",
+      "name": "GetResponseContentType24",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -614,7 +614,7 @@
     {
       "$id": "74",
       "kind": "constant",
-      "name": "XmlErrorContentType25",
+      "name": "GetResponseContentType25",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -630,7 +630,7 @@
     {
       "$id": "76",
       "kind": "constant",
-      "name": "XmlErrorContentType26",
+      "name": "GetResponseContentType26",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -662,7 +662,7 @@
     {
       "$id": "80",
       "kind": "constant",
-      "name": "XmlErrorContentType27",
+      "name": "GetResponseContentType27",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -678,7 +678,7 @@
     {
       "$id": "82",
       "kind": "constant",
-      "name": "XmlErrorContentType28",
+      "name": "GetResponseContentType28",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -694,7 +694,7 @@
     {
       "$id": "84",
       "kind": "constant",
-      "name": "XmlErrorContentType29",
+      "name": "GetResponseContentType29",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -726,7 +726,7 @@
     {
       "$id": "88",
       "kind": "constant",
-      "name": "XmlErrorContentType30",
+      "name": "GetResponseContentType30",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -742,7 +742,7 @@
     {
       "$id": "90",
       "kind": "constant",
-      "name": "XmlErrorContentType31",
+      "name": "GetResponseContentType31",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -758,7 +758,7 @@
     {
       "$id": "92",
       "kind": "constant",
-      "name": "XmlErrorContentType32",
+      "name": "GetResponseContentType32",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -790,7 +790,7 @@
     {
       "$id": "96",
       "kind": "constant",
-      "name": "XmlErrorContentType33",
+      "name": "GetResponseContentType33",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -806,7 +806,7 @@
     {
       "$id": "98",
       "kind": "constant",
-      "name": "XmlErrorContentType34",
+      "name": "GetResponseContentType34",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -822,7 +822,7 @@
     {
       "$id": "100",
       "kind": "constant",
-      "name": "XmlErrorContentType35",
+      "name": "GetResponseContentType35",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -854,7 +854,7 @@
     {
       "$id": "104",
       "kind": "constant",
-      "name": "XmlErrorContentType36",
+      "name": "GetResponseContentType36",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -870,7 +870,7 @@
     {
       "$id": "106",
       "kind": "constant",
-      "name": "XmlErrorContentType37",
+      "name": "GetResponseContentType37",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -886,7 +886,7 @@
     {
       "$id": "108",
       "kind": "constant",
-      "name": "XmlErrorContentType38",
+      "name": "GetResponseContentType38",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -918,7 +918,7 @@
     {
       "$id": "112",
       "kind": "constant",
-      "name": "XmlErrorContentType39",
+      "name": "GetResponseContentType39",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -934,7 +934,7 @@
     {
       "$id": "114",
       "kind": "constant",
-      "name": "XmlErrorContentType40",
+      "name": "GetResponseContentType40",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -950,7 +950,7 @@
     {
       "$id": "116",
       "kind": "constant",
-      "name": "XmlErrorContentType41",
+      "name": "GetResponseContentType41",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -982,7 +982,7 @@
     {
       "$id": "120",
       "kind": "constant",
-      "name": "XmlErrorContentType42",
+      "name": "GetResponseContentType42",
       "namespace": "",
       "usage": "None",
       "valueType": {
diff --git a/packages/http-client-csharp/generator/TestProjects/Spector/http/type/union/tspCodeModel.json b/packages/http-client-csharp/generator/TestProjects/Spector/http/type/union/tspCodeModel.json
index 7b5c6d926d3..2c21b31efe3 100644
--- a/packages/http-client-csharp/generator/TestProjects/Spector/http/type/union/tspCodeModel.json
+++ b/packages/http-client-csharp/generator/TestProjects/Spector/http/type/union/tspCodeModel.json
@@ -394,7 +394,7 @@
     {
       "$id": "34",
       "kind": "constant",
-      "name": "MixedLiteralsCasesStringLiteral1",
+      "name": "GetResponseProp5",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -410,7 +410,7 @@
     {
       "$id": "36",
       "kind": "constant",
-      "name": "MixedLiteralsCasesStringLiteral2",
+      "name": "GetResponseProp6",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -426,7 +426,7 @@
     {
       "$id": "38",
       "kind": "constant",
-      "name": "MixedLiteralsCasesStringLiteral3",
+      "name": "GetResponseProp7",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -442,7 +442,7 @@
     {
       "$id": "40",
       "kind": "constant",
-      "name": "MixedLiteralsCasesStringLiteral4",
+      "name": "MixedLiteralsCasesStringLiteral1",
       "namespace": "",
       "usage": "None",
       "valueType": {
@@ -458,7 +458,7 @@
     {
       "$id": "42",
       "kind": "constant",
-      "name": "MixedLiteralsCasesStringLiteral11",
+      "name": "GetResponseProp51",
       "namespace": "",
       "usage": "None",
       "valueType": {
diff --git a/packages/http-client-csharp/package-lock.json b/packages/http-client-csharp/package-lock.json
index 3f4c49f696c..e8812c1af42 100644
--- a/packages/http-client-csharp/package-lock.json
+++ b/packages/http-client-csharp/package-lock.json
@@ -11,7 +11,7 @@
       "devDependencies": {
         "@azure-tools/azure-http-specs": "0.1.0-alpha.38",
         "@azure-tools/typespec-azure-core": "0.66.0",
-        "@azure-tools/typespec-client-generator-core": "0.66.0",
+        "@azure-tools/typespec-client-generator-core": "0.66.2",
         "@microsoft/api-extractor": "^7.52.2",
         "@types/node": "~22.12.0",
         "@typespec/compiler": "1.10.0",
@@ -35,7 +35,7 @@
         "vitest": "^3.0.5"
       },
       "peerDependencies": {
-        "@azure-tools/typespec-client-generator-core": ">=0.66.0 <0.67.0 || ~0.67.0-0",
+        "@azure-tools/typespec-client-generator-core": ">=0.66.2 <0.67.0 || ~0.67.0-0",
         "@typespec/compiler": "^1.10.0",
         "@typespec/http": "^1.10.0",
         "@typespec/openapi": "^1.10.0",
@@ -134,9 +134,9 @@
       }
     },
     "node_modules/@azure-tools/typespec-client-generator-core": {
-      "version": "0.66.0",
-      "resolved": "https://registry.npmjs.org/@azure-tools/typespec-client-generator-core/-/typespec-client-generator-core-0.66.0.tgz",
-      "integrity": "sha512-ITg9Ls1p0vr1nTM6BaeO+u3p5+jkJ6JtzomrUAhgBNQUZGsC5MIOt4leOJf8XMBCwW3WFLIRRVF86xMgamMfDA==",
+      "version": "0.66.2",
+      "resolved": "https://registry.npmjs.org/@azure-tools/typespec-client-generator-core/-/typespec-client-generator-core-0.66.2.tgz",
+      "integrity": "sha512-Qr5fstJ0yQiTYNvp/EuY3+mUBue2ri9qNZkT6aC+CsfBt5yjfdjo++3SuEsDQtELyS8pBoDOT3weLiB0N+/fSw==",
       "dev": true,
       "license": "MIT",
       "dependencies": {
diff --git a/packages/http-client-csharp/package.json b/packages/http-client-csharp/package.json
index 80f74950682..283b0f46bb1 100644
--- a/packages/http-client-csharp/package.json
+++ b/packages/http-client-csharp/package.json
@@ -52,7 +52,7 @@
     "emitter/lib/*.tsp"
   ],
   "peerDependencies": {
-    "@azure-tools/typespec-client-generator-core": ">=0.66.0 <0.67.0 || ~0.67.0-0",
+    "@azure-tools/typespec-client-generator-core": ">=0.66.2 <0.67.0 || ~0.67.0-0",
     "@typespec/compiler": "^1.10.0",
     "@typespec/http": "^1.10.0",
     "@typespec/openapi": "^1.10.0",
@@ -64,7 +64,7 @@
   "devDependencies": {
     "@azure-tools/azure-http-specs": "0.1.0-alpha.38",
     "@azure-tools/typespec-azure-core": "0.66.0",
-    "@azure-tools/typespec-client-generator-core": "0.66.0",
+    "@azure-tools/typespec-client-generator-core": "0.66.2",
     "@microsoft/api-extractor": "^7.52.2",
     "@types/node": "~22.12.0",
     "@typespec/compiler": "1.10.0",