diff --git a/.chronus/changes/add_on_validate-2024-1-26-14-11-57.md b/.chronus/changes/add_on_validate-2024-1-26-14-11-57.md
new file mode 100644
index 0000000000..bd8dd46b3c
--- /dev/null
+++ b/.chronus/changes/add_on_validate-2024-1-26-14-11-57.md
@@ -0,0 +1,7 @@
+---
+changeKind: feature
+packages:
+  - "@azure-tools/typespec-client-generator-core"
+---
+
+add validation on import of tcgc and remove duplicate validation warnings
\ No newline at end of file
diff --git a/packages/typespec-client-generator-core/src/decorators.ts b/packages/typespec-client-generator-core/src/decorators.ts
index 6ab122392c..b1bb827a29 100644
--- a/packages/typespec-client-generator-core/src/decorators.ts
+++ b/packages/typespec-client-generator-core/src/decorators.ts
@@ -33,21 +33,21 @@ import {
   SdkEmitterOptions,
   SdkOperationGroup,
 } from "./interfaces.js";
-import { parseEmitterName } from "./internal-utils.js";
+import { TCGCContext, createTCGCContext, parseEmitterName } from "./internal-utils.js";
 import { createStateSymbol, reportDiagnostic } from "./lib.js";
 import { getAllModels, getSdkEnum, getSdkModel } from "./types.js";
 
 export const namespace = "Azure.ClientGenerator.Core";
 const AllScopes = Symbol.for("@azure-core/typespec-client-generator-core/all-scopes");
 
-function getScopedDecoratorData(context: SdkContext, key: symbol, target: Type): any {
+function getScopedDecoratorData(context: TCGCContext, key: symbol, target: Type): any {
   const retval: Record<string | symbol, any> = context.program.stateMap(key).get(target);
   if (retval === undefined) return retval;
   if (Object.keys(retval).includes(context.emitterName)) return retval[context.emitterName];
   return retval[AllScopes]; // in this case it applies to all languages
 }
 
-function listScopedDecoratorData(context: SdkContext, key: symbol): any[] {
+function listScopedDecoratorData(context: TCGCContext, key: symbol): any[] {
   const retval = [...context.program.stateMap(key).values()];
   return retval
     .filter((targetEntry) => {
@@ -161,11 +161,14 @@ function findClientService(
 /**
  * Return the client object for the given namespace or interface, or undefined if the given namespace or interface is not a client.
  *
- * @param context SdkContext
+ * @param context TCGCContext
  * @param type Type to check
  * @returns Client or undefined
  */
-export function getClient(context: SdkContext, type: Namespace | Interface): SdkClient | undefined {
+export function getClient(
+  context: TCGCContext,
+  type: Namespace | Interface
+): SdkClient | undefined {
   if (hasExplicitClientOrOperationGroup(context)) {
     return getScopedDecoratorData(context, clientKey, type);
   }
@@ -183,7 +186,7 @@ export function getClient(context: SdkContext, type: Namespace | Interface): Sdk
   return undefined;
 }
 
-function hasExplicitClientOrOperationGroup(context: SdkContext): boolean {
+function hasExplicitClientOrOperationGroup(context: TCGCContext): boolean {
   return (
     listScopedDecoratorData(context, clientKey).length > 0 ||
     listScopedDecoratorData(context, operationGroupKey).length > 0
@@ -193,10 +196,10 @@ function hasExplicitClientOrOperationGroup(context: SdkContext): boolean {
 /**
  * List all the clients.
  *
- * @param context SdkContext
+ * @param context TCGCContext
  * @returns Array of clients
  */
-export function listClients(context: SdkContext): SdkClient[] {
+export function listClients(context: TCGCContext): SdkClient[] {
   const explicitClients = [...listScopedDecoratorData(context, clientKey)];
   if (explicitClients.length > 0) {
     return explicitClients;
@@ -255,11 +258,11 @@ export function $operationGroup(
 
 /**
  * Check a namespace or interface is an operation group.
- * @param context SdkContext
+ * @param context TCGCContext
  * @param type Type to check
  * @returns boolean
  */
-export function isOperationGroup(context: SdkContext, type: Namespace | Interface): boolean {
+export function isOperationGroup(context: TCGCContext, type: Namespace | Interface): boolean {
   if (hasExplicitClientOrOperationGroup(context)) {
     return getScopedDecoratorData(context, operationGroupKey, type) !== undefined;
   }
@@ -274,12 +277,12 @@ export function isOperationGroup(context: SdkContext, type: Namespace | Interfac
 }
 /**
  * Check an operation is in an operation group.
- * @param context SdkContext
+ * @param context TCGCContext
  * @param type Type to check
  * @returns boolean
  */
 export function isInOperationGroup(
-  context: SdkContext,
+  context: TCGCContext,
   type: Namespace | Interface | Operation
 ): boolean {
   switch (type.kind) {
@@ -298,7 +301,7 @@ export function isInOperationGroup(
   }
 }
 
-function buildOperationGroupPath(context: SdkContext, type: Namespace | Interface): string {
+function buildOperationGroupPath(context: TCGCContext, type: Namespace | Interface): string {
   const path = [];
   while (true) {
     const client = getClient(context, type);
@@ -319,12 +322,12 @@ function buildOperationGroupPath(context: SdkContext, type: Namespace | Interfac
 }
 /**
  * Return the operation group object for the given namespace or interface or undefined is not an operation group.
- * @param context SdkContext
+ * @param context TCGCContext
  * @param type Type to check
  * @returns Operation group or undefined.
  */
 export function getOperationGroup(
-  context: SdkContext,
+  context: TCGCContext,
   type: Namespace | Interface
 ): SdkOperationGroup | undefined {
   let operationGroup: SdkOperationGroup | undefined;
@@ -381,13 +384,13 @@ export function getOperationGroup(
 /**
  * List all the operation groups inside a client or an operation group. If ignoreHierarchy is true, the result will include all nested operation groups.
  *
- * @param context SdkContext
+ * @param context TCGCContext
  * @param group Client or operation group to list operation groups
  * @param ignoreHierarchy Whether to get all nested operation groups
  * @returns
  */
 export function listOperationGroups(
-  context: SdkContext,
+  context: TCGCContext,
   group: SdkClient | SdkOperationGroup,
   ignoreHierarchy = false
 ): SdkOperationGroup[] {
@@ -421,13 +424,13 @@ export function listOperationGroups(
 
 /**
  * List operations inside a client or an operation group. If ignoreHierarchy is true, the result will include all nested operations.
- * @param program SdkContext
+ * @param program TCGCContext
  * @param group Client or operation group to list operations
  * @param ignoreHierarchy Whether to get all nested operations
  * @returns
  */
 export function listOperationsInOperationGroup(
-  context: SdkContext,
+  context: TCGCContext,
   group: SdkOperationGroup | SdkClient,
   ignoreHierarchy = false
 ): Operation[] {
@@ -477,7 +480,7 @@ export function createSdkContext<TOptions extends Record<string, any> = SdkEmitt
   const generateConvenienceMethods =
     context.options["generate-convenience-methods"] ?? convenienceOptions;
   return {
-    program: context.program,
+    ...createTCGCContext(context.program),
     emitContext: context,
     emitterName: parseEmitterName(emitterName ?? context.program.emitters[0]?.metadata?.name), // eslint-disable-line deprecation/deprecation
     generateProtocolMethods: generateProtocolMethods,
@@ -509,14 +512,14 @@ export function $convenientAPI(
   setScopedDecoratorData(context, $convenientAPI, convenientAPIKey, entity, value, scope);
 }
 
-export function shouldGenerateProtocol(context: SdkContext, entity: Operation): boolean {
+export function shouldGenerateProtocol(context: TCGCContext, entity: Operation): boolean {
   const value = getScopedDecoratorData(context, protocolAPIKey, entity);
-  return value ?? context.generateProtocolMethods;
+  return value ?? !!context.generateProtocolMethods;
 }
 
-export function shouldGenerateConvenient(context: SdkContext, entity: Operation): boolean {
+export function shouldGenerateConvenient(context: TCGCContext, entity: Operation): boolean {
   const value = getScopedDecoratorData(context, convenientAPIKey, entity);
-  return value ?? context.generateConvenienceMethods;
+  return value ?? !!context.generateConvenienceMethods;
 }
 
 const excludeKey = createStateSymbol("exclude");
@@ -540,14 +543,14 @@ export function $include(context: DecoratorContext, entity: Model, scope?: Langu
 /**
  * @deprecated This function is unused and will be removed in a future release.
  */
-export function isExclude(context: SdkContext, entity: Model): boolean {
+export function isExclude(context: TCGCContext, entity: Model): boolean {
   return getScopedDecoratorData(context, excludeKey, entity) ?? false;
 }
 
 /**
  * @deprecated This function is unused and will be removed in a future release.
  */
-export function isInclude(context: SdkContext, entity: Model): boolean {
+export function isInclude(context: TCGCContext, entity: Model): boolean {
   return getScopedDecoratorData(context, includeKey, entity) ?? false;
 }
 
@@ -619,7 +622,7 @@ export function $clientFormat(
  * @deprecated This function is unused and will be removed in a future release.
  */
 export function getClientFormat(
-  context: SdkContext,
+  context: TCGCContext,
   entity: ModelProperty
 ): ClientFormat | undefined {
   let retval: ClientFormat | undefined = getScopedDecoratorData(context, clientFormatKey, entity);
@@ -654,12 +657,15 @@ export function $internal(context: DecoratorContext, target: Operation, scope?:
  * Whether a model / operation is internal or not. If it's internal, emitters
  * should not expose them to users
  *
- * @param context SdkContext
+ * @param context TCGCContext
  * @param entity model / operation that we want to check is internal or not
  * @returns whether the entity is internal
  * @deprecated This function is unused and will be removed in a future release.
  */
-export function isInternal(context: SdkContext, entity: Model | Operation | Enum | Union): boolean {
+export function isInternal(
+  context: TCGCContext,
+  entity: Model | Operation | Enum | Union
+): boolean {
   const found = getScopedDecoratorData(context, internalKey, entity) ?? false;
   if (entity.kind === "Operation" || found) {
     return found;
@@ -722,13 +728,13 @@ export function $usage(
 }
 
 export function getUsageOverride(
-  context: SdkContext,
+  context: TCGCContext,
   entity: Model | Enum
 ): UsageFlags | undefined {
   return getScopedDecoratorData(context, usageKey, entity);
 }
 
-export function getUsage(context: SdkContext, entity: Model | Enum): UsageFlags {
+export function getUsage(context: TCGCContext, entity: Model | Enum): UsageFlags {
   if (!context.modelsMap) {
     getAllModels(context); // this will populate modelsMap
   }
@@ -756,14 +762,14 @@ export function $access(
 }
 
 export function getAccessOverride(
-  context: SdkContext,
+  context: TCGCContext,
   entity: Model | Enum | Operation
 ): AccessFlags | undefined {
   return getScopedDecoratorData(context, accessKey, entity);
 }
 
 export function getAccess(
-  context: SdkContext,
+  context: TCGCContext,
   entity: Model | Enum | Operation
 ): AccessFlags | undefined {
   const override = getScopedDecoratorData(context, accessKey, entity);
@@ -800,11 +806,11 @@ export function $flattenProperty(
 /**
  * Whether a model property should be flattened or not.
  *
- * @param context SdkContext
+ * @param context TCGCContext
  * @param target ModelProperty that we want to check whether it should be flattened or not
  * @returns whether the model property should be flattened or not
  */
-export function shouldFlattenProperty(context: SdkContext, target: ModelProperty): boolean {
+export function shouldFlattenProperty(context: TCGCContext, target: ModelProperty): boolean {
   return getScopedDecoratorData(context, flattenPropertyKey, target) ?? false;
 }
 
@@ -819,6 +825,6 @@ export function $clientName(
   setScopedDecoratorData(context, $clientName, clientNameKey, entity, value, scope);
 }
 
-export function getClientNameOverride(context: SdkContext, entity: Type): string | undefined {
+export function getClientNameOverride(context: TCGCContext, entity: Type): string | undefined {
   return getScopedDecoratorData(context, clientNameKey, entity);
 }
diff --git a/packages/typespec-client-generator-core/src/interfaces.ts b/packages/typespec-client-generator-core/src/interfaces.ts
index e80299d99c..047637f921 100644
--- a/packages/typespec-client-generator-core/src/interfaces.ts
+++ b/packages/typespec-client-generator-core/src/interfaces.ts
@@ -5,8 +5,6 @@ import {
   Interface,
   ModelProperty,
   Namespace,
-  Operation,
-  Program,
   Type,
   UsageFlags,
 } from "@typespec/compiler";
@@ -18,6 +16,7 @@ import {
   HttpVerb,
   Visibility,
 } from "@typespec/http";
+import { TCGCContext } from "./internal-utils.js";
 
 export type SdkParameterLocation =
   | "endpointPath"
@@ -28,18 +27,8 @@ export type SdkParameterLocation =
   | "unknown";
 export type SdkParameterImplementation = "Client" | "Method";
 
-export interface SdkContext<TOptions extends object = Record<string, any>> {
-  program: Program;
+export interface SdkContext<TOptions extends object = Record<string, any>> extends TCGCContext {
   emitContext: EmitContext<TOptions>;
-  emitterName: string;
-  generateProtocolMethods: boolean;
-  generateConvenienceMethods: boolean;
-  filterOutCoreModels?: boolean;
-  packageName?: string;
-  modelsMap?: Map<Type, SdkModelType | SdkEnumType>;
-  operationModelsMap?: Map<Operation, Map<Type, SdkModelType | SdkEnumType>>;
-  generatedNames?: Set<string>;
-  arm?: boolean;
 }
 
 export interface SdkEmitterOptions {
diff --git a/packages/typespec-client-generator-core/src/internal-utils.ts b/packages/typespec-client-generator-core/src/internal-utils.ts
index 2b3d1bcbd2..23c13d83f7 100644
--- a/packages/typespec-client-generator-core/src/internal-utils.ts
+++ b/packages/typespec-client-generator-core/src/internal-utils.ts
@@ -1,3 +1,6 @@
+import { Operation, Program, Type } from "@typespec/compiler";
+import { SdkEnumType, SdkModelType } from "./interfaces.js";
+
 export function parseEmitterName(emitterName?: string): string {
   if (!emitterName) {
     throw new Error("No emitter name found in program");
@@ -9,3 +12,23 @@ export function parseEmitterName(emitterName?: string): string {
   if (["typescript", "ts"].includes(language)) return "javascript";
   return language;
 }
+
+export interface TCGCContext {
+  program: Program;
+  emitterName: string;
+  generateProtocolMethods?: boolean;
+  generateConvenienceMethods?: boolean;
+  filterOutCoreModels?: boolean;
+  packageName?: string;
+  arm?: boolean;
+  modelsMap?: Map<Type, SdkModelType | SdkEnumType>;
+  operationModelsMap?: Map<Operation, Map<Type, SdkModelType | SdkEnumType>>;
+  generatedNames?: Set<string>;
+}
+
+export function createTCGCContext(program: Program): TCGCContext {
+  return {
+    program,
+    emitterName: "__TCGC_INTERNAL__",
+  };
+}
diff --git a/packages/typespec-client-generator-core/src/public-utils.ts b/packages/typespec-client-generator-core/src/public-utils.ts
index e4ae05314e..11976fcc97 100644
--- a/packages/typespec-client-generator-core/src/public-utils.ts
+++ b/packages/typespec-client-generator-core/src/public-utils.ts
@@ -34,8 +34,7 @@ import {
   listOperationGroups,
   listOperationsInOperationGroup,
 } from "./decorators.js";
-import { SdkContext } from "./interfaces.js";
-import { parseEmitterName } from "./internal-utils.js";
+import { parseEmitterName, TCGCContext } from "./internal-utils.js";
 import { reportDiagnostic } from "./lib.js";
 
 /**
@@ -45,7 +44,7 @@ import { reportDiagnostic } from "./lib.js";
  * @returns
  */
 export function getDefaultApiVersion(
-  context: SdkContext,
+  context: TCGCContext,
   serviceNamespace: Namespace
 ): Version | undefined {
   try {
@@ -63,7 +62,7 @@ export function getDefaultApiVersion(
  * @returns
  */
 export function isApiVersion(
-  context: SdkContext,
+  context: TCGCContext,
   parameter: HttpOperationParameter | ModelProperty
 ): boolean {
   return (
@@ -78,7 +77,7 @@ export function isApiVersion(
  * @param context
  * @returns
  */
-export function getClientNamespaceString(context: SdkContext): string | undefined {
+export function getClientNamespaceString(context: TCGCContext): string | undefined {
   let packageName = context.packageName;
   if (packageName) {
     packageName = packageName
@@ -102,7 +101,7 @@ export function getClientNamespaceString(context: SdkContext): string | undefine
  * @param type
  * @returns
  */
-export function getEffectivePayloadType(context: SdkContext, type: Model): Model {
+export function getEffectivePayloadType(context: TCGCContext, type: Model): Model {
   const program = context.program;
 
   // if a type has name, we should resolve the name
@@ -148,7 +147,7 @@ export function isAzureCoreModel(t: Type): boolean {
  *
  * @deprecated This function is deprecated. Please pass in your emitter name as a parameter name to createSdkContext
  */
-export function getEmitterTargetName(context: SdkContext): string {
+export function getEmitterTargetName(context: TCGCContext): string {
   return parseEmitterName(context.program.emitters[0]?.metadata?.name); // eslint-disable-line deprecation/deprecation
 }
 
@@ -158,7 +157,7 @@ export function getEmitterTargetName(context: SdkContext): string {
  * @param property
  * @returns a tuple of the library and wire name for a model property
  */
-export function getPropertyNames(context: SdkContext, property: ModelProperty): [string, string] {
+export function getPropertyNames(context: TCGCContext, property: ModelProperty): [string, string] {
   return [getLibraryName(context, property), getWireName(context, property)];
 }
 
@@ -176,7 +175,7 @@ export function getPropertyNames(context: SdkContext, property: ModelProperty):
  * @param type
  * @returns the library name for a typespec type
  */
-export function getLibraryName(context: SdkContext, type: Type & { name?: string }): string {
+export function getLibraryName(context: TCGCContext, type: Type & { name?: string }): string {
   // 1. check if there's a client name
   let emitterSpecificName = getClientNameOverride(context, type);
   if (emitterSpecificName) return emitterSpecificName;
@@ -197,7 +196,7 @@ export function capitalize(name: string): string {
   return name[0].toUpperCase() + name.slice(1);
 }
 
-export function reportUnionUnsupported(context: SdkContext, type: Union): void {
+export function reportUnionUnsupported(context: TCGCContext, type: Union): void {
   reportDiagnostic(context.program, { code: "union-unsupported", target: type });
 }
 
@@ -210,7 +209,7 @@ interface DocWrapper {
   details?: string;
 }
 
-export function getDocHelper(context: SdkContext, type: Type): DocWrapper {
+export function getDocHelper(context: TCGCContext, type: Type): DocWrapper {
   if (getSummary(context.program, type)) {
     return {
       description: getSummary(context.program, type),
@@ -222,7 +221,7 @@ export function getDocHelper(context: SdkContext, type: Type): DocWrapper {
   };
 }
 
-export function getWireName(context: SdkContext, type: Type & { name: string }) {
+export function getWireName(context: TCGCContext, type: Type & { name: string }) {
   // 1. Check if there's an encoded name
   const encodedName = resolveEncodedName(context.program, type, "application/json");
   if (encodedName !== type.name) return encodedName;
@@ -242,7 +241,7 @@ interface SdkTypeBaseHelper<TKind> {
  * @param type
  */
 export function getSdkTypeBaseHelper<TKind>(
-  context: SdkContext,
+  context: TCGCContext,
   type: Type | string,
   kind: TKind
 ): SdkTypeBaseHelper<TKind> {
@@ -287,7 +286,7 @@ export function getCrossLanguageDefinitionId(type: {
  * @param type
  */
 export function getGeneratedName(
-  context: SdkContext,
+  context: TCGCContext,
   type: Model | Union,
   operation?: Operation
 ): string {
@@ -308,7 +307,7 @@ export function getGeneratedName(
  * @param type
  * @returns
  */
-function findContextPath(context: SdkContext, type: Model | Union): ContextNode[] {
+function findContextPath(context: TCGCContext, type: Model | Union): ContextNode[] {
   for (const client of listClients(context)) {
     for (const operation of listOperationsInOperationGroup(context, client)) {
       const result = getContextPath(context, operation, type);
@@ -350,7 +349,7 @@ interface ContextNode {
  * @returns
  */
 function getContextPath(
-  context: SdkContext,
+  context: TCGCContext,
   root: Operation | Model,
   typeToFind: Model | Union
 ): ContextNode[] {
@@ -490,7 +489,7 @@ function getContextPath(
  * @param contextPaths
  * @returns
  */
-function buildNameFromContextPaths(context: SdkContext, contextPath: ContextNode[]): string {
+function buildNameFromContextPaths(context: TCGCContext, contextPath: ContextNode[]): string {
   // fallback to empty name for corner case
   if (contextPath.length === 0) {
     return "";
diff --git a/packages/typespec-client-generator-core/src/types.ts b/packages/typespec-client-generator-core/src/types.ts
index b962eb7f95..4eed12aee0 100644
--- a/packages/typespec-client-generator-core/src/types.ts
+++ b/packages/typespec-client-generator-core/src/types.ts
@@ -61,7 +61,6 @@ import {
   SdkBuiltInKinds,
   SdkBuiltInType,
   SdkConstantType,
-  SdkContext,
   SdkDatetimeType,
   SdkDictionaryType,
   SdkDurationType,
@@ -85,14 +84,16 @@ import {
   isAzureCoreModel,
 } from "./public-utils.js";
 
-function getAnyType(context: SdkContext, type: Type): SdkBuiltInType {
+import { TCGCContext } from "./internal-utils.js";
+
+function getAnyType(context: TCGCContext, type: Type): SdkBuiltInType {
   return {
     ...getSdkTypeBaseHelper(context, type, "any"),
     encode: getEncodeHelper(context, type, "any"),
   };
 }
 
-function getEncodeHelper(context: SdkContext, type: Type, kind: string): string {
+function getEncodeHelper(context: TCGCContext, type: Type, kind: string): string {
   if (type.kind === "ModelProperty" || type.kind === "Scalar") {
     return getEncode(context.program, type)?.encoding || kind;
   }
@@ -108,7 +109,7 @@ function getEncodeHelper(context: SdkContext, type: Type, kind: string): string
  * @param propertyType the type of the property, i.e. the internal type that we add the format info onto
  */
 function addFormatInfo(
-  context: SdkContext,
+  context: TCGCContext,
   type: ModelProperty | Scalar,
   propertyType: SdkType
 ): void {
@@ -149,7 +150,7 @@ function addFormatInfo(
  * @param propertyType the type of the property, i.e. the internal type that we add the encoding info onto
  */
 function addEncodeInfo(
-  context: SdkContext,
+  context: TCGCContext,
   type: ModelProperty | Scalar,
   propertyType: SdkType
 ): [void, readonly Diagnostic[]] {
@@ -224,7 +225,7 @@ function getScalarKind(scalar: Scalar): SdkBuiltInKinds {
  * @returns the corresponding sdk type
  */
 export function getSdkBuiltInType(
-  context: SdkContext,
+  context: TCGCContext,
   type: Scalar | IntrinsicType | NumericLiteral | StringLiteral | BooleanLiteral
 ): SdkBuiltInType {
   if (context.program.checker.isStdType(type) || type.kind === "Intrinsic") {
@@ -254,7 +255,7 @@ export function getSdkBuiltInType(
   throw Error(`Unknown kind ${type.kind}`);
 }
 
-export function getSdkDurationType(context: SdkContext, type: Scalar): SdkDurationType {
+export function getSdkDurationType(context: TCGCContext, type: Scalar): SdkDurationType {
   // we don't get encode info until we get to the property / parameter level
   // so we insert the default. Later in properties, we will check
   // for encoding info and override accordingly
@@ -266,7 +267,7 @@ export function getSdkDurationType(context: SdkContext, type: Scalar): SdkDurati
 }
 
 export function getSdkArrayOrDict(
-  context: SdkContext,
+  context: TCGCContext,
   type: Model,
   operation?: Operation
 ): [(SdkDictionaryType | SdkArrayType) | undefined, readonly Diagnostic[]] {
@@ -301,7 +302,7 @@ export function getSdkArrayOrDict(
 }
 
 export function getSdkTuple(
-  context: SdkContext,
+  context: TCGCContext,
   type: Tuple,
   operation?: Operation
 ): [SdkTupleType, readonly Diagnostic[]] {
@@ -314,12 +315,12 @@ export function getSdkTuple(
   });
 }
 
-function getNonNullOptions(context: SdkContext, type: Union): Type[] {
+function getNonNullOptions(context: TCGCContext, type: Union): Type[] {
   return [...type.variants.values()].map((x) => x.type).filter((t) => !isNullType(t));
 }
 
 export function getSdkUnion(
-  context: SdkContext,
+  context: TCGCContext,
   type: Union,
   operation?: Operation
 ): [SdkType, readonly Diagnostic[]] {
@@ -350,7 +351,7 @@ export function getSdkUnion(
 }
 
 export function getSdkConstant(
-  context: SdkContext,
+  context: TCGCContext,
   type: StringLiteral | NumericLiteral | BooleanLiteral
 ): SdkConstantType {
   switch (type.kind) {
@@ -367,7 +368,7 @@ export function getSdkConstant(
 }
 
 function addDiscriminatorToModelType(
-  context: SdkContext,
+  context: TCGCContext,
   type: Model,
   model: SdkModelType,
   operation?: Operation
@@ -455,7 +456,7 @@ function addDiscriminatorToModelType(
 }
 
 export function getSdkModel(
-  context: SdkContext,
+  context: TCGCContext,
   type: Model,
   operation?: Operation
 ): [SdkModelType, readonly Diagnostic[]] {
@@ -531,7 +532,7 @@ export function getSdkModel(
 }
 
 function getSdkEnumValueType(
-  context: SdkContext,
+  context: TCGCContext,
   type: EnumMember | StringLiteral | NumericLiteral
 ): SdkBuiltInType {
   let kind: "string" | "int32" | "float32" = "string";
@@ -545,7 +546,7 @@ function getSdkEnumValueType(
 }
 
 export function getSdkEnumValue(
-  context: SdkContext,
+  context: TCGCContext,
   enumType: SdkEnumType,
   type: EnumMember
 ): SdkEnumValueType {
@@ -561,7 +562,7 @@ export function getSdkEnumValue(
   };
 }
 
-export function getSdkEnum(context: SdkContext, type: Enum, operation?: Operation): SdkEnumType {
+export function getSdkEnum(context: TCGCContext, type: Enum, operation?: Operation): SdkEnumType {
   let sdkType = context.modelsMap?.get(type) as SdkEnumType | undefined;
   if (!sdkType) {
     const docWrapper = getDocHelper(context, type);
@@ -587,7 +588,7 @@ export function getSdkEnum(context: SdkContext, type: Enum, operation?: Operatio
 }
 
 function getSdkUnionEnumValues(
-  context: SdkContext,
+  context: TCGCContext,
   type: UnionEnum,
   enumType: SdkEnumType
 ): SdkEnumValueType[] {
@@ -608,7 +609,7 @@ function getSdkUnionEnumValues(
   return values;
 }
 
-function getSdkUnionEnum(context: SdkContext, type: UnionEnum, operation?: Operation) {
+function getSdkUnionEnum(context: TCGCContext, type: UnionEnum, operation?: Operation) {
   let sdkType = context.modelsMap?.get(type.union) as SdkEnumType | undefined;
   if (!sdkType) {
     const union = type.union as Union & { name: string };
@@ -634,7 +635,7 @@ function getSdkUnionEnum(context: SdkContext, type: UnionEnum, operation?: Opera
 }
 
 function getKnownValuesEnum(
-  context: SdkContext,
+  context: TCGCContext,
   type: Scalar | ModelProperty,
   operation?: Operation
 ): SdkEnumType | undefined {
@@ -672,7 +673,7 @@ function getKnownValuesEnum(
 }
 
 export function getClientTypeWithDiagnostics(
-  context: SdkContext,
+  context: TCGCContext,
   type: Type,
   operation?: Operation
 ): [SdkType, readonly Diagnostic[]] {
@@ -759,7 +760,7 @@ export function getClientTypeWithDiagnostics(
   return diagnostics.wrap(retval);
 }
 
-export function getClientType(context: SdkContext, type: Type, operation?: Operation): SdkType {
+export function getClientType(context: TCGCContext, type: Type, operation?: Operation): SdkType {
   return ignoreDiagnostics(getClientTypeWithDiagnostics(context, type, operation));
 }
 
@@ -774,7 +775,7 @@ export function isReadOnly(property: SdkBodyModelPropertyType) {
   return false;
 }
 
-function getSdkVisibility(context: SdkContext, type: ModelProperty): Visibility[] | undefined {
+function getSdkVisibility(context: TCGCContext, type: ModelProperty): Visibility[] | undefined {
   const visibility = getVisibility(context.program, type);
   if (visibility) {
     const result = [];
@@ -798,7 +799,7 @@ function getSdkVisibility(context: SdkContext, type: ModelProperty): Visibility[
   return undefined;
 }
 
-function getAvailableApiVersions(context: SdkContext, type: Type): string[] {
+function getAvailableApiVersions(context: TCGCContext, type: Type): string[] {
   const allVersions = getVersions(context.program, type)[1]?.getVersions() ?? [];
   const addedOnVersions = getAddedOnVersions(context.program, type)?.map((x) => x.value) ?? [];
   const removedOnVersions = getRemovedOnVersions(context.program, type)?.map((x) => x.value) ?? [];
@@ -824,7 +825,7 @@ function getAvailableApiVersions(context: SdkContext, type: Type): string[] {
 }
 
 function getSdkModelPropertyType(
-  context: SdkContext,
+  context: TCGCContext,
   type: ModelProperty,
   operation?: Operation
 ): [SdkModelPropertyTypeBase, readonly Diagnostic[]] {
@@ -849,7 +850,7 @@ function getSdkModelPropertyType(
 }
 
 function getSdkBodyModelPropertyType(
-  context: SdkContext,
+  context: TCGCContext,
   type: ModelProperty,
   operation?: Operation
 ): [SdkBodyModelPropertyType, readonly Diagnostic[]] {
@@ -887,7 +888,7 @@ function getSdkBodyModelPropertyType(
 }
 
 function addPropertiesToModelType(
-  context: SdkContext,
+  context: TCGCContext,
   type: Model,
   sdkType: SdkType,
   operation?: Operation
@@ -916,7 +917,12 @@ function addPropertiesToModelType(
   return diagnostics.wrap(undefined);
 }
 
-function updateModelsMap(context: SdkContext, type: Type, sdkType: SdkType, operation?: Operation) {
+function updateModelsMap(
+  context: TCGCContext,
+  type: Type,
+  sdkType: SdkType,
+  operation?: Operation
+) {
   if (sdkType.kind !== "model" && sdkType.kind !== "enum") {
     return;
   }
@@ -983,7 +989,7 @@ function updateModelsMap(context: SdkContext, type: Type, sdkType: SdkType, oper
 }
 
 function checkAndGetClientType(
-  context: SdkContext,
+  context: TCGCContext,
   type: Type,
   operation?: Operation
 ): [SdkType | undefined, readonly Diagnostic[]] {
@@ -999,7 +1005,7 @@ function checkAndGetClientType(
 }
 
 function updateUsageOfModel(
-  context: SdkContext,
+  context: TCGCContext,
   type: SdkType,
   usage: UsageFlags,
   seenModelNames?: Set<SdkType>
@@ -1049,7 +1055,7 @@ function updateUsageOfModel(
 }
 
 function updateTypesFromOperation(
-  context: SdkContext,
+  context: TCGCContext,
   operation: Operation
 ): [void, readonly Diagnostic[]] {
   const diagnostics = createDiagnosticCollector();
@@ -1105,7 +1111,7 @@ function updateTypesFromOperation(
   return diagnostics.wrap(undefined);
 }
 
-function updateAccessOfModel(context: SdkContext): void {
+function updateAccessOfModel(context: TCGCContext): void {
   for (const [type, sdkType] of context.modelsMap?.entries() ?? []) {
     const internal = isInternal(context, type as any); // eslint-disable-line deprecation/deprecation
     if (internal) {
@@ -1146,7 +1152,7 @@ interface GetAllModelsOptions {
   output?: boolean;
 }
 
-function handleServiceOrphanType(context: SdkContext, type: Model | Enum) {
+function handleServiceOrphanType(context: TCGCContext, type: Model | Enum) {
   const diagnostics = createDiagnosticCollector();
   // eslint-disable-next-line deprecation/deprecation
   if (type.kind === "Model" && isInclude(context, type)) {
@@ -1164,7 +1170,7 @@ function handleServiceOrphanType(context: SdkContext, type: Model | Enum) {
 }
 
 export function getAllModelsWithDiagnostics(
-  context: SdkContext,
+  context: TCGCContext,
   options: GetAllModelsOptions = {}
 ): [(SdkModelType | SdkEnumType)[], readonly Diagnostic[]] {
   const diagnostics = createDiagnosticCollector();
@@ -1228,11 +1234,11 @@ export function getAllModelsWithDiagnostics(
 }
 
 export function getAllModels(
-  context: SdkContext,
+  context: TCGCContext,
   options: GetAllModelsOptions = {}
 ): (SdkModelType | SdkEnumType)[] {
   // we currently don't return diagnostics even though we keep track of them
   // when we move to the new sdk type ecosystem completely, we'll expose
-  // diagnostics as a separate property on the sdkContext
+  // diagnostics as a separate property on the TCGCContext
   return ignoreDiagnostics(getAllModelsWithDiagnostics(context, options));
 }
diff --git a/packages/typespec-client-generator-core/src/validate.ts b/packages/typespec-client-generator-core/src/validate.ts
new file mode 100644
index 0000000000..833c7fcdbb
--- /dev/null
+++ b/packages/typespec-client-generator-core/src/validate.ts
@@ -0,0 +1,12 @@
+import { Program } from "@typespec/compiler";
+import { createTCGCContext } from "./internal-utils.js";
+import { getAllModelsWithDiagnostics } from "./types.js";
+
+export function $onValidate(program: Program) {
+  // Pass along any diagnostics that might be returned from the HTTP library
+  const tcgcContext = createTCGCContext(program);
+  const [_, diagnostics] = getAllModelsWithDiagnostics(tcgcContext);
+  if (diagnostics.length > 0) {
+    program.reportDiagnostics(diagnostics);
+  }
+}