diff --git a/.chronus/changes/fix-js-option-forwarding-2026-08-17.md b/.chronus/changes/fix-js-option-forwarding-2026-08-17.md
new file mode 100644
index 0000000000..b72519b27c
--- /dev/null
+++ b/.chronus/changes/fix-js-option-forwarding-2026-08-17.md
@@ -0,0 +1,8 @@
+---
+changeKind: fix
+packages:
+  - "@azure-tools/typespec-ts"
+---
+
+Forward legacy headers, credential scopes, and logging options in modular clients, including a
+deprecated package-local `credentialScopes` alias for clients that use OAuth scopes.
diff --git a/packages/typespec-ts/src/modular/build-client-context.ts b/packages/typespec-ts/src/modular/build-client-context.ts
index 91cdd3ca5e..aa3c734494 100644
--- a/packages/typespec-ts/src/modular/build-client-context.ts
+++ b/packages/typespec-ts/src/modular/build-client-context.ts
@@ -135,6 +135,17 @@ export function buildClientContext(
         docs: getDocsWithKnownVersion(dpgContext, p),
       };
     });
+  if (
+    emitterOptions.options.addCredentials &&
+    emitterOptions.options.credentialScopes !== undefined
+  ) {
+    propertiesInOptions.push({
+      name: "credentialScopes",
+      type: "string | string[]",
+      hasQuestionToken: true,
+      docs: ["@deprecated Use `credentials.scopes` instead."],
+    });
+  }
   if (dpgContext.arm) {
     propertiesInOptions.push({
       name: "cloudSetting",
diff --git a/packages/typespec-ts/src/modular/helpers/client-helpers.ts b/packages/typespec-ts/src/modular/helpers/client-helpers.ts
index 369c350743..59fdc61e7d 100644
--- a/packages/typespec-ts/src/modular/helpers/client-helpers.ts
+++ b/packages/typespec-ts/src/modular/helpers/client-helpers.ts
@@ -298,7 +298,9 @@ function buildCredentials(
   const scopesString = credentialScopes
     ? credentialScopes.map((cs) => `"${cs}"`).join(", ") || `\`\${${endpointParam}}/.default\``
     : "";
-  const scopes = scopesString ? `scopes: options.credentials?.scopes ?? [${scopesString}],` : "";
+  const scopes = scopesString
+    ? `scopes: options.credentials?.scopes ?? (typeof options.credentialScopes === "string" ? [options.credentialScopes] : options.credentialScopes) ?? [${scopesString}],`
+    : "";
 
   const apiKeyHeaderName = credentialKeyHeaderName
     ? `apiKeyHeaderName: options.credentials?.apiKeyHeaderName ?? "${credentialKeyHeaderName}",`
@@ -312,7 +314,7 @@ function buildCredentials(
 }
 
 function buildLoggingOptions(): string | undefined {
-  return `{ logger: options.loggingOptions?.logger ?? logger.info }`;
+  return `{ ...options.loggingOptions, logger: options.loggingOptions?.logger ?? logger.info }`;
 }
 
 /**
diff --git a/packages/typespec-ts/src/modular/helpers/operation-helpers.ts b/packages/typespec-ts/src/modular/helpers/operation-helpers.ts
index 5de6b9629c..4aa550a68b 100644
--- a/packages/typespec-ts/src/modular/helpers/operation-helpers.ts
+++ b/packages/typespec-ts/src/modular/helpers/operation-helpers.ts
@@ -126,6 +126,7 @@ export function getSendPrivateFunction(
   const operationMethod = operation.operation.verb.toLowerCase();
   const optionalParamName = getOptionalParamsName(parameters);
   const statements: string[] = [];
+  const parameterNames = new Set(parameters.map((p) => p.name));
   let pathStr = `"${operationPath}"`;
   const urlTemplateParams = [
     ...getPathParameters(operation),
@@ -133,8 +134,7 @@ export function getSendPrivateFunction(
   ];
   if (urlTemplateParams.length > 0) {
     // Generate a unique local variable name that doesn't conflict with parameter names
-    const paramNames = new Set(parameters.map((p) => p.name));
-    const pathVarName = generateLocallyUniqueName("path", paramNames);
+    const pathVarName = generateLocallyUniqueName("path", parameterNames);
     const includeRootSlash = client ? getClientOptions(client, "includeRootSlash") !== false : true;
 
     const uriTemplate = includeRootSlash
@@ -149,12 +149,26 @@ export function getSendPrivateFunction(
     pathStr = pathVarName;
   }
 
+  const requestParametersName = generateLocallyUniqueName("requestParameters", parameterNames);
+  const headerAndBodyParameters = getHeaderAndBodyParameters(
+    dpgContext,
+    operation,
+    optionalParamName,
+    requestParametersName,
+  );
+  const operationOptionsExpression = `${resolveReference(
+    dependencies.operationOptionsToRequestParameters,
+  )}(${optionalParamName})`;
+  const requestParametersExpression = headerAndBodyParameters.hasHeaders
+    ? requestParametersName
+    : operationOptionsExpression;
+
+  if (headerAndBodyParameters.hasHeaders) {
+    statements.push(`const ${requestParametersName} = ${operationOptionsExpression};`);
+  }
+
   statements.push(
-    `return context.path(${pathStr}).${operationMethod}({...${resolveReference(dependencies.operationOptionsToRequestParameters)}(${optionalParamName}), ${getHeaderAndBodyParameters(
-      dpgContext,
-      operation,
-      optionalParamName,
-    )}});`,
+    `return context.path(${pathStr}).${operationMethod}({...${requestParametersExpression}, ${headerAndBodyParameters.value}});`,
   );
 
   return {
@@ -1413,9 +1427,10 @@ function getHeaderAndBodyParameters(
   dpgContext: SdkContext,
   operation: ServiceOperation,
   optionalParamName: string = "options",
-): string {
+  requestParametersName: string = "requestParameters",
+): { value: string; hasHeaders: boolean } {
   if (!operation.operation.parameters) {
-    return "";
+    return { value: "", hasHeaders: false };
   }
   const operationParameters = operation.operation.parameters.filter((p) => !isContentType(p));
 
@@ -1464,7 +1479,7 @@ function getHeaderAndBodyParameters(
   if (parametersImplementation.header.length) {
     paramStr = `${paramStr}\nheaders: {${parametersImplementation.header
       .map((i) => buildHeaderParameter(dpgContext.program, i.paramMap, i.param, i.paramAccessor))
-      .join(",\n")}, ...${optionalParamName}.requestOptions?.headers },`;
+      .join(",\n")}, ...${requestParametersName}.headers },`;
   }
   if (operation.operation.bodyParam === undefined && parametersImplementation.body.length) {
     paramStr = `${paramStr}\nbody: {${parametersImplementation.body
@@ -1473,7 +1488,7 @@ function getHeaderAndBodyParameters(
   } else if (operation.operation.bodyParam !== undefined) {
     paramStr = `${paramStr}${buildBodyParameter(dpgContext, operation.operation.bodyParam)}`;
   }
-  return paramStr;
+  return { value: paramStr, hasHeaders: parametersImplementation.header.length > 0 };
 }
 
 // Specially handle the type for headers because we only allow string/number/boolean values
diff --git a/packages/typespec-ts/test/azure-modular-integration/generated/authentication/oauth2/src/index.d.ts b/packages/typespec-ts/test/azure-modular-integration/generated/authentication/oauth2/src/index.d.ts
index 9a0b3a4b40..a794aee7d3 100644
--- a/packages/typespec-ts/test/azure-modular-integration/generated/authentication/oauth2/src/index.d.ts
+++ b/packages/typespec-ts/test/azure-modular-integration/generated/authentication/oauth2/src/index.d.ts
@@ -23,6 +23,7 @@ export declare class OAuth2Client {
 }
 
 export declare interface OAuth2ClientOptionalParams extends ClientOptions {
+    credentialScopes?: string | string[];
 }
 
 export { RestError }
diff --git a/packages/typespec-ts/test/azure-modular-integration/generated/authentication/union/src/index.d.ts b/packages/typespec-ts/test/azure-modular-integration/generated/authentication/union/src/index.d.ts
index 980ee6e5bf..82a3ee0ca8 100644
--- a/packages/typespec-ts/test/azure-modular-integration/generated/authentication/union/src/index.d.ts
+++ b/packages/typespec-ts/test/azure-modular-integration/generated/authentication/union/src/index.d.ts
@@ -19,6 +19,7 @@ export declare class UnionClient {
 }
 
 export declare interface UnionClientOptionalParams extends ClientOptions {
+    credentialScopes?: string | string[];
 }
 
 export declare interface ValidKeyOptionalParams extends OperationOptions {
diff --git a/packages/typespec-ts/test/modular-unit/client-options.test.ts b/packages/typespec-ts/test/modular-unit/client-options.test.ts
new file mode 100644
index 0000000000..20be8f0e7c
--- /dev/null
+++ b/packages/typespec-ts/test/modular-unit/client-options.test.ts
@@ -0,0 +1,120 @@
+import { afterAll, assert, describe, it } from "vitest";
+
+import { Project } from "ts-morph";
+import { buildGetClientOptionsParam } from "../../src/modular/helpers/client-helpers.js";
+import type { ModularEmitterOptions } from "../../src/modular/interfaces.js";
+import {
+  emitModularClientContextFromTypeSpec,
+  emitModularOperationsFromTypeSpec,
+} from "../util/emit-util.js";
+import { clearCompileCache } from "../util/test-util.js";
+
+afterAll(clearCompileCache);
+
+describe("client option forwarding", () => {
+  const credentialSpec = `
+    import "@typespec/http";
+    import "@typespec/rest";
+    import "@azure-tools/typespec-azure-core";
+
+    using TypeSpec.Http;
+    using TypeSpec.Rest;
+    using Azure.Core;
+
+    @useAuth(
+      OAuth2Auth<[
+        {
+          type: OAuth2FlowType.implicit,
+          authorizationUrl: "https://login.microsoftonline.com/common/oauth2/authorize",
+          scopes: ["https://example.com/.default"],
+        }
+      ]>
+    )
+    @service(#{ title: "ScopeClient" })
+    @server("{endpoint}", "Service endpoint", { endpoint: url })
+    namespace ScopeService;
+
+    @route("/read")
+    @get
+    op read(): void;
+  `;
+
+  it("merges normalized operation headers with generated service headers", async () => {
+    const result = await emitModularOperationsFromTypeSpec(`
+      @route("/read")
+      @get
+      op read(@header("x-service-header") serviceHeader: string): void;
+    `);
+    const text = result![0]!.getFullText();
+
+    assert.include(text, "const requestParameters = operationOptionsToRequestParameters(options);");
+    assert.include(text, '"x-service-header": serviceHeader');
+    // The core helper folds deprecated customHeaders into this normalized headers bag.
+    assert.include(text, "...requestParameters.headers");
+    assert.notInclude(text, "...options.requestOptions?.headers");
+  });
+
+  it("normalizes legacy credential scopes after current credential options", () => {
+    const text = emitGetClientOptions();
+    const currentScopes = text.indexOf("options.credentials?.scopes");
+    const legacyStringScopes = text.indexOf('typeof options.credentialScopes === "string"');
+    const legacyArrayScopes = text.indexOf(": options.credentialScopes");
+    const generatedScopes = text.indexOf('"https://example.com/.default"');
+
+    assert.isAtLeast(currentScopes, 0);
+    assert.isAbove(legacyStringScopes, currentScopes);
+    assert.include(text, "? [options.credentialScopes]");
+    assert.isAbove(legacyArrayScopes, legacyStringScopes);
+    assert.isAbove(generatedScopes, legacyArrayScopes);
+  });
+
+  it("declares the deprecated credential scopes alias on scoped client options only", async () => {
+    const scopedResult = await emitModularClientContextFromTypeSpec(credentialSpec, {
+      "add-credentials": true,
+      "credential-scopes": ["https://example.com/.default"],
+    });
+    const scopedText = scopedResult!.getFullText();
+
+    assert.include(
+      scopedText,
+      "export interface ScopeServiceClientOptionalParams extends ClientOptions",
+    );
+    assert.include(scopedText, "@deprecated Use `credentials.scopes` instead.");
+    assert.include(scopedText, "credentialScopes?: string | string[];");
+
+    const unscopedResult = await emitModularClientContextFromTypeSpec(`
+      @route("/read")
+      @get
+      op read(): void;
+    `);
+    assert.notInclude(unscopedResult!.getFullText(), "credentialScopes");
+  });
+
+  it("preserves logging header and query allowlists while defaulting the logger", () => {
+    const text = emitGetClientOptions();
+
+    assert.include(
+      text,
+      "loggingOptions: { ...options.loggingOptions, logger: options.loggingOptions?.logger ?? logger.info }",
+    );
+  });
+});
+
+function emitGetClientOptions(): string {
+  const project = new Project({ useInMemoryFileSystem: true });
+  const factory = project.createSourceFile("client.ts").addFunction({ name: "createClient" });
+  const emitterOptions: ModularEmitterOptions = {
+    options: {
+      addCredentials: true,
+      credentialScopes: ["https://example.com/.default"],
+    },
+    modularOptions: {
+      sourceRoot: "",
+      compatibilityMode: false,
+      experimentalExtensibleEnums: false,
+    },
+  };
+
+  buildGetClientOptionsParam(factory, emitterOptions, "endpoint");
+  return factory.getText();
+}
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/anonymous/anonymous.md b/packages/typespec-ts/test/modular-unit/scenarios/anonymous/anonymous.md
index 8682671e94..746bcb30ab 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/anonymous/anonymous.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/anonymous/anonymous.md
@@ -892,9 +892,10 @@ export function _readSend(
   context: Client,
   options: ReadOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
@@ -962,9 +963,10 @@ export function _readSend(
   context: Client,
   options: ReadOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
@@ -1049,9 +1051,10 @@ export function _readSend(
   context: Client,
   options: ReadOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
@@ -1209,9 +1212,10 @@ export function _readSend(
   context: Client,
   options: ReadOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
@@ -1424,9 +1428,10 @@ export function _readSend(
   context: Client,
   options: ReadOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/api-operations/apiOperations.md b/packages/typespec-ts/test/modular-unit/scenarios/api-operations/apiOperations.md
index 4076c937d8..5b0fe827f6 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/api-operations/apiOperations.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/api-operations/apiOperations.md
@@ -321,9 +321,10 @@ export function _downloadFileSend(
   context: Client,
   options: DownloadFileOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/downloadFile").post({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/octet-stream", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/octet-stream", ...requestParameters.headers },
   });
 }
 
@@ -378,9 +379,10 @@ export function _downloadFileSend(
   context: Client,
   options: DownloadFileOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/downloadFile").post({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/octet-stream", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/octet-stream", ...requestParameters.headers },
   });
 }
 
@@ -500,9 +502,10 @@ export function _testSend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "text/plain", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "text/plain", ...requestParameters.headers },
   });
 }
 
@@ -542,7 +545,10 @@ export function createTesting(
   const endpointUrl = options.endpoint ?? String(endpointParam);
   const { apiVersion: _, ...updatedOptions } = {
     ...options,
-    loggingOptions: { logger: options.loggingOptions?.logger ?? logger.info },
+    loggingOptions: {
+      ...options.loggingOptions,
+      logger: options.loggingOptions?.logger ?? logger.info,
+    },
   };
   const clientContext = getClient(endpointUrl, undefined, updatedOptions);
 
@@ -628,9 +634,10 @@ export function _testSend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "text/plain", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "text/plain", ...requestParameters.headers },
   });
 }
 
@@ -670,7 +677,10 @@ export function createTesting(
   const endpointUrl = options.endpoint ?? String(endpointParam);
   const { apiVersion: _, ...updatedOptions } = {
     ...options,
-    loggingOptions: { logger: options.loggingOptions?.logger ?? logger.info },
+    loggingOptions: {
+      ...options.loggingOptions,
+      logger: options.loggingOptions?.logger ?? logger.info,
+    },
   };
   const clientContext = getClient(endpointUrl, undefined, updatedOptions);
 
@@ -740,9 +750,10 @@ export function _test1Send(
   context: Client,
   options: Test1OptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/test1").get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "text/plain", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "text/plain", ...requestParameters.headers },
   });
 }
 
@@ -776,9 +787,10 @@ export function _testSend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "text/plain", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "text/plain", ...requestParameters.headers },
   });
 }
 
@@ -818,7 +830,10 @@ export function createTesting(
   const endpointUrl = options.endpoint ?? String(endpointParam);
   const { apiVersion: _, ...updatedOptions } = {
     ...options,
-    loggingOptions: { logger: options.loggingOptions?.logger ?? logger.info },
+    loggingOptions: {
+      ...options.loggingOptions,
+      logger: options.loggingOptions?.logger ?? logger.info,
+    },
   };
   const clientContext = getClient(endpointUrl, undefined, updatedOptions);
 
@@ -1057,9 +1072,10 @@ export function _listSend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/api-operations/azureCoreOperations.md b/packages/typespec-ts/test/modular-unit/scenarios/api-operations/azureCoreOperations.md
index 2661f00223..c995dcb30a 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/api-operations/azureCoreOperations.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/api-operations/azureCoreOperations.md
@@ -83,9 +83,10 @@ export function _getWidgetOperationStatusSend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/api-operations/reservedWordOperations.md b/packages/typespec-ts/test/modular-unit/scenarios/api-operations/reservedWordOperations.md
index 2287b92008..a810a0a5ce 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/api-operations/reservedWordOperations.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/api-operations/reservedWordOperations.md
@@ -26,9 +26,10 @@ export function _$continueSend(
   context: Client,
   options: ContinueOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
@@ -82,9 +83,10 @@ export function _$returnSend(
   context: Client,
   options: ReturnOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
@@ -138,9 +140,10 @@ export function _globalSend(
   context: Client,
   options: GlobalOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/client-context/clientContext.md b/packages/typespec-ts/test/modular-unit/scenarios/client-context/clientContext.md
index 11f56bae3e..2a341e1668 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/client-context/clientContext.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/client-context/clientContext.md
@@ -79,7 +79,10 @@ export function createService(
   const endpointUrl = options.endpoint ?? `${endpointParam}/client/structure/${clientParam}`;
   const { apiVersion: _, ...updatedOptions } = {
     ...options,
-    loggingOptions: { logger: options.loggingOptions?.logger ?? logger.info },
+    loggingOptions: {
+      ...options.loggingOptions,
+      logger: options.loggingOptions?.logger ?? logger.info,
+    },
   };
   const clientContext = getClient(endpointUrl, undefined, updatedOptions);
 
@@ -173,7 +176,10 @@ export function createService(options: ServiceClientOptionalParams = {}): Servic
   const endpointUrl = options.endpoint ?? `${endpointParam}/client/structure/${clientParam}`;
   const { apiVersion: _, ...updatedOptions } = {
     ...options,
-    loggingOptions: { logger: options.loggingOptions?.logger ?? logger.info },
+    loggingOptions: {
+      ...options.loggingOptions,
+      logger: options.loggingOptions?.logger ?? logger.info,
+    },
   };
   const clientContext = getClient(endpointUrl, undefined, updatedOptions);
 
@@ -269,7 +275,10 @@ export function createTestService(
   const endpointUrl = options.endpoint ?? `${endpointParam}/client/structure/${clientParam}`;
   const { apiVersion: _, ...updatedOptions } = {
     ...options,
-    loggingOptions: { logger: options.loggingOptions?.logger ?? logger.info },
+    loggingOptions: {
+      ...options.loggingOptions,
+      logger: options.loggingOptions?.logger ?? logger.info,
+    },
   };
   const clientContext = getClient(endpointUrl, undefined, updatedOptions);
 
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/client-context/optionalApiVersion.md b/packages/typespec-ts/test/modular-unit/scenarios/client-context/optionalApiVersion.md
index 5cad458555..17bff8af45 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/client-context/optionalApiVersion.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/client-context/optionalApiVersion.md
@@ -78,7 +78,10 @@ export function createDataMapService(
   const endpointUrl = options.endpoint ?? String(endpointParam);
   const { apiVersion: _, ...updatedOptions } = {
     ...options,
-    loggingOptions: { logger: options.loggingOptions?.logger ?? logger.info },
+    loggingOptions: {
+      ...options.loggingOptions,
+      logger: options.loggingOptions?.logger ?? logger.info,
+    },
   };
   const clientContext = getClient(endpointUrl, undefined, updatedOptions);
   const apiVersion = options.apiVersion;
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/enum-union/enumUnion.md b/packages/typespec-ts/test/modular-unit/scenarios/enum-union/enumUnion.md
index 62ff12bfba..5193423843 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/enum-union/enumUnion.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/enum-union/enumUnion.md
@@ -528,10 +528,11 @@ export function _getSend(
   body: string,
   options: GetOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "text/plain",
-    headers: { "test-header": testHeader, ...options.requestOptions?.headers },
+    headers: { "test-header": testHeader, ...requestParameters.headers },
     body: body,
   });
 }
@@ -609,10 +610,11 @@ export function _getSend(
   body: string,
   options: GetOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "text/plain",
-    headers: { "test-header": testHeader, ...options.requestOptions?.headers },
+    headers: { "test-header": testHeader, ...requestParameters.headers },
     body: body,
   });
 }
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/example/example.md b/packages/typespec-ts/test/modular-unit/scenarios/example/example.md
index e985e6bf9a..c32c117c00 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/example/example.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/example/example.md
@@ -116,9 +116,10 @@ export function _readSend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/models-generator/modelsGenerator.md b/packages/typespec-ts/test/modular-unit/scenarios/models-generator/modelsGenerator.md
index 10dfac7677..fdb4289651 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/models-generator/modelsGenerator.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/models-generator/modelsGenerator.md
@@ -453,10 +453,11 @@ export function _readSend(
   body: Foo,
   options: ReadOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "application/json",
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    headers: { accept: "application/json", ...requestParameters.headers },
     body: fooSerializer(body),
   });
 }
@@ -504,9 +505,10 @@ export function _readSend(
   prop: Date,
   options: ReadOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { prop: prop.toUTCString(), ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { prop: prop.toUTCString(), ...requestParameters.headers },
   });
 }
 
@@ -587,10 +589,11 @@ export function _readSend(
   body: Foo,
   options: ReadOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "application/json",
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    headers: { accept: "application/json", ...requestParameters.headers },
     body: fooSerializer(body),
   });
 }
@@ -672,10 +675,11 @@ export function _readSend(
   body: Foo,
   options: ReadOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "application/json",
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    headers: { accept: "application/json", ...requestParameters.headers },
     body: fooSerializer(body),
   });
 }
@@ -753,10 +757,11 @@ export function _readSend(
   body: Foo,
   options: ReadOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "application/json",
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    headers: { accept: "application/json", ...requestParameters.headers },
     body: fooSerializer(body),
   });
 }
@@ -825,10 +830,11 @@ export function _readSend(
   body: Foo,
   options: ReadOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "application/json",
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    headers: { accept: "application/json", ...requestParameters.headers },
     body: fooSerializer(body),
   });
 }
@@ -898,10 +904,11 @@ export function _readSend(
   body: Foo,
   options: ReadOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "application/json",
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    headers: { accept: "application/json", ...requestParameters.headers },
     body: fooSerializer(body),
   });
 }
@@ -975,10 +982,11 @@ export function _readSend(
   body: Foo,
   options: ReadOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "application/json",
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    headers: { accept: "application/json", ...requestParameters.headers },
     body: fooSerializer(body),
   });
 }
@@ -1062,10 +1070,11 @@ export function _readSend(
   body: Foo,
   options: ReadOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "application/json",
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    headers: { accept: "application/json", ...requestParameters.headers },
     body: fooSerializer(body),
   });
 }
@@ -1150,10 +1159,11 @@ export function _readSend(
   body: Foo,
   options: ReadOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "application/json",
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    headers: { accept: "application/json", ...requestParameters.headers },
     body: fooSerializer(body),
   });
 }
@@ -1238,10 +1248,11 @@ export function _readSend(
   body: Foo,
   options: ReadOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "application/json",
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    headers: { accept: "application/json", ...requestParameters.headers },
     body: fooSerializer(body),
   });
 }
@@ -1423,9 +1434,10 @@ export function _readSend(
   context: Client,
   options: ReadOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
@@ -1531,9 +1543,10 @@ export function _readSend(
   context: Client,
   options: ReadOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
@@ -1667,10 +1680,11 @@ export function _readSend(
   body: PSDog,
   options: ReadOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "application/json",
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    headers: { accept: "application/json", ...requestParameters.headers },
     body: psDogSerializer(body),
   });
 }
@@ -1805,9 +1819,10 @@ export function _readSend(
   context: Client,
   options: ReadOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
@@ -1984,9 +1999,10 @@ export function _readSend(
   context: Client,
   options: ReadOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
@@ -2078,9 +2094,10 @@ export function _readSend(
   context: Client,
   options: ReadOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
@@ -2303,10 +2320,11 @@ export function _getSend(
   body: string,
   options: GetOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "text/plain",
-    headers: { "test-header": testHeader, ...options.requestOptions?.headers },
+    headers: { "test-header": testHeader, ...requestParameters.headers },
     body: body,
   });
 }
@@ -2880,10 +2898,11 @@ export function _readSend(
   body: Client_1,
   options: ReadOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "application/json",
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    headers: { accept: "application/json", ...requestParameters.headers },
     body: clientSerializer(body),
   });
 }
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/models/api-version/apiVersionAsFixedEnum.md b/packages/typespec-ts/test/modular-unit/scenarios/models/api-version/apiVersionAsFixedEnum.md
index 0f71f13abf..9f5100c6a1 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/models/api-version/apiVersionAsFixedEnum.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/models/api-version/apiVersionAsFixedEnum.md
@@ -65,11 +65,12 @@ export function _fooSend(
   context: Client,
   options: FooOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").get({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     headers: {
       "api-version": context.apiVersion ?? "2021-10-01-preview",
-      ...options.requestOptions?.headers,
+      ...requestParameters.headers,
     },
   });
 }
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/models/azureCoreErrorModels.md b/packages/typespec-ts/test/modular-unit/scenarios/models/azureCoreErrorModels.md
index 8b5f50633d..ed6e8e26d2 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/models/azureCoreErrorModels.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/models/azureCoreErrorModels.md
@@ -396,10 +396,11 @@ export function _createOrUpdateSend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).put({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "application/json",
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    headers: { accept: "application/json", ...requestParameters.headers },
     body: avsSummarySerializer(resource),
   });
 }
@@ -450,9 +451,10 @@ export function _listSend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/models/missingErrorResponseModel.md b/packages/typespec-ts/test/modular-unit/scenarios/models/missingErrorResponseModel.md
index 3bb104414c..bc740b53fd 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/models/missingErrorResponseModel.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/models/missingErrorResponseModel.md
@@ -115,9 +115,10 @@ export function _getAssetChainSummarySend(
   context: Client,
   options: GetAssetChainSummaryOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/assetChainSummary").get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/models/models.md b/packages/typespec-ts/test/modular-unit/scenarios/models/models.md
index 022f269322..af6a5d3674 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/models/models.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/models/models.md
@@ -79,10 +79,11 @@ export function _readSend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "application/json",
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    headers: { accept: "application/json", ...requestParameters.headers },
     body: streamingChatCompletionOptionsSerializer(body),
   });
 }
@@ -145,10 +146,11 @@ export function _readSend(
   context: Client,
   options: ReadOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "application/json",
-    headers: { accept: "text/plain", ...options.requestOptions?.headers },
+    headers: { accept: "text/plain", ...requestParameters.headers },
     body: { stream: true, messages: "aaaaa", index: 123 },
   });
 }
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/models/nullable/nullableUnion.md b/packages/typespec-ts/test/modular-unit/scenarios/models/nullable/nullableUnion.md
index 612d2c8e93..3867197660 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/models/nullable/nullableUnion.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/models/nullable/nullableUnion.md
@@ -74,10 +74,11 @@ export function _postSend(
   body: A,
   options: PostOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "application/json",
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    headers: { accept: "application/json", ...requestParameters.headers },
     body: !body ? body : _postRequestSerializer(body),
   });
 }
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/models/response/headerCollectionPrefixRequiredSkipSignature.md b/packages/typespec-ts/test/modular-unit/scenarios/models/response/headerCollectionPrefixRequiredSkipSignature.md
index 77e9e3edf9..e047d1ec81 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/models/response/headerCollectionPrefixRequiredSkipSignature.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/models/response/headerCollectionPrefixRequiredSkipSignature.md
@@ -65,12 +65,13 @@ export function _getBlobSend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).get({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     headers: {
       ...(options?.requestId !== undefined ? { "x-ms-request-id": options?.requestId } : {}),
       accept: "application/json",
-      ...options.requestOptions?.headers,
+      ...requestParameters.headers,
     },
   });
 }
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/models/response/headerCollectionPrefixSkipSerialization.md b/packages/typespec-ts/test/modular-unit/scenarios/models/response/headerCollectionPrefixSkipSerialization.md
index 80fc2f449d..bf55fb9caf 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/models/response/headerCollectionPrefixSkipSerialization.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/models/response/headerCollectionPrefixSkipSerialization.md
@@ -82,12 +82,13 @@ export function _getBlobSend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).get({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     headers: {
       ...(options?.requestId !== undefined ? { "x-ms-request-id": options?.requestId } : {}),
       accept: "application/json",
-      ...options.requestOptions?.headers,
+      ...requestParameters.headers,
     },
   });
 }
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/models/treatUnknownAsRecord.md b/packages/typespec-ts/test/modular-unit/scenarios/models/treatUnknownAsRecord.md
index 6cdb621b1e..64ede7f8a3 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/models/treatUnknownAsRecord.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/models/treatUnknownAsRecord.md
@@ -101,9 +101,10 @@ export function _getAnySend(
   context: Client,
   options: GetAnyOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/any").get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/operations/armPatchWithUnionResponse.md b/packages/typespec-ts/test/modular-unit/scenarios/operations/armPatchWithUnionResponse.md
index 5f0c153599..3a099f2d54 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/operations/armPatchWithUnionResponse.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/operations/armPatchWithUnionResponse.md
@@ -97,10 +97,11 @@ export function _updateSend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).patch({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "application/json",
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    headers: { accept: "application/json", ...requestParameters.headers },
     body: partnerTopicUpdateParametersSerializer(properties),
   });
 }
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/operations/body-param/bytesWithDifferentContentType.md b/packages/typespec-ts/test/modular-unit/scenarios/operations/body-param/bytesWithDifferentContentType.md
index c1eddde983..eb07a8c6c4 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/operations/body-param/bytesWithDifferentContentType.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/operations/body-param/bytesWithDifferentContentType.md
@@ -36,10 +36,11 @@ export function _uploadFileSend(
   body: string,
   options: UploadFileOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "text/plain",
-    headers: { accept: "*/*", ...options.requestOptions?.headers },
+    headers: { accept: "*/*", ...requestParameters.headers },
     body: body,
   });
 }
@@ -128,10 +129,11 @@ export function _uploadFileSend(
   body: Uint8Array,
   options: UploadFileOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "application/octet-stream",
-    headers: { accept: "application/xml", ...options.requestOptions?.headers },
+    headers: { accept: "application/xml", ...requestParameters.headers },
     body: body,
   });
 }
@@ -221,10 +223,11 @@ export function _uploadFileSend(
   body: Uint8Array,
   options: UploadFileOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "application/octet-stream",
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    headers: { accept: "application/json", ...requestParameters.headers },
     body: body,
   });
 }
@@ -314,10 +317,11 @@ export function _uploadFileSend(
   body: Uint8Array,
   options: UploadFileOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "application/octet-stream",
-    headers: { accept: "text/plain", ...options.requestOptions?.headers },
+    headers: { accept: "text/plain", ...requestParameters.headers },
     body: body,
   });
 }
@@ -403,10 +407,11 @@ export function _uploadFileSend(
   body: Uint8Array,
   options: UploadFileOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "application/octet-stream",
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    headers: { accept: "application/json", ...requestParameters.headers },
     body: body,
   });
 }
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/operations/bodyMetadataExtraction.md b/packages/typespec-ts/test/modular-unit/scenarios/operations/bodyMetadataExtraction.md
index 8cb02bbed3..29caf45471 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/operations/bodyMetadataExtraction.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/operations/bodyMetadataExtraction.md
@@ -68,10 +68,11 @@ export function _bodyRootWithHeaderSend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "application/json",
-    headers: { foo: body.foo, ...options.requestOptions?.headers },
+    headers: { foo: body.foo, ...requestParameters.headers },
     body: requestBodySerializer(body),
   });
 }
@@ -256,12 +257,13 @@ export function _bodyRootWithOptionalHeaderSend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "application/json",
     headers: {
       ...(body.foo !== undefined ? { foo: body.foo } : {}),
-      ...options.requestOptions?.headers,
+      ...requestParameters.headers,
     },
     body: optionalHeaderBodySerializer(body),
   });
@@ -449,12 +451,13 @@ export function _createOptionalPathResourceSend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "application/json",
     headers: {
       ...(options?.body?.foo !== undefined ? { foo: options?.body?.foo } : {}),
-      ...options.requestOptions?.headers,
+      ...requestParameters.headers,
     },
     body: {
       body: !options?.body ? options?.body : optionalBodyWithHeaderSerializer(options?.body),
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/operations/clientDefaultValue.md b/packages/typespec-ts/test/modular-unit/scenarios/operations/clientDefaultValue.md
index 65ff41c94e..57d44211c5 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/operations/clientDefaultValue.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/operations/clientDefaultValue.md
@@ -74,10 +74,11 @@ export function _createSend(
   context: Client,
   options: CreateOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/api/create").post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "text/plain",
-    headers: { accept: "text/plain", ...options.requestOptions?.headers },
+    headers: { accept: "text/plain", ...requestParameters.headers },
     body: options?.body ?? "default-body",
   });
 }
@@ -115,12 +116,13 @@ export function _testQuerySend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).get({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     headers: {
       "custom-header": options?.customHeader ?? "application/json",
       accept: "application/json",
-      ...options.requestOptions?.headers,
+      ...requestParameters.headers,
     },
   });
 }
@@ -201,10 +203,11 @@ export function _createRequiredSend(
   body: string,
   options: CreateRequiredOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/api/createRequired").post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "text/plain",
-    headers: { accept: "text/plain", ...options.requestOptions?.headers },
+    headers: { accept: "text/plain", ...requestParameters.headers },
     body: body,
   });
 }
@@ -243,12 +246,13 @@ export function _testRequiredSend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).get({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     headers: {
       "custom-header": customHeader,
       accept: "application/json",
-      ...options.requestOptions?.headers,
+      ...requestParameters.headers,
     },
   });
 }
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/operations/cookie-param/ignoreCookieParam.md b/packages/typespec-ts/test/modular-unit/scenarios/operations/cookie-param/ignoreCookieParam.md
index d745a03e9a..00673f4af2 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/operations/cookie-param/ignoreCookieParam.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/operations/cookie-param/ignoreCookieParam.md
@@ -36,9 +36,10 @@ export function _testSend(
   context: Client,
   options: TestOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "text/plain", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "text/plain", ...requestParameters.headers },
   });
 }
 
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/operations/deserializeEmptyBody.md b/packages/typespec-ts/test/modular-unit/scenarios/operations/deserializeEmptyBody.md
index 2729daa372..bc6dd9cd8a 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/operations/deserializeEmptyBody.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/operations/deserializeEmptyBody.md
@@ -52,9 +52,10 @@ export function _deleteKeyValueSend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).delete({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
@@ -134,9 +135,10 @@ export function _getResourceSend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
@@ -224,9 +226,10 @@ export function _deleteKeyValueSend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).delete({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/operations/error-deserialization/xmlErrorDeserialization.md b/packages/typespec-ts/test/modular-unit/scenarios/operations/error-deserialization/xmlErrorDeserialization.md
index abd6f497ad..afc815ab3d 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/operations/error-deserialization/xmlErrorDeserialization.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/operations/error-deserialization/xmlErrorDeserialization.md
@@ -51,9 +51,10 @@ export function _getWidgetSend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
@@ -148,9 +149,10 @@ export function _getDocumentSend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json, application/xml", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json, application/xml", ...requestParameters.headers },
   });
 }
 
@@ -251,9 +253,10 @@ export function _getItemSend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/operations/header-param/headerParamWithClientInitialization.md b/packages/typespec-ts/test/modular-unit/scenarios/operations/header-param/headerParamWithClientInitialization.md
index 36cd3c638a..12f63e6f30 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/operations/header-param/headerParamWithClientInitialization.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/operations/header-param/headerParamWithClientInitialization.md
@@ -130,7 +130,10 @@ export function createBillingBenefits(
   const endpointUrl = options.endpoint ?? String(endpointParam);
   const { apiVersion: _, ...updatedOptions } = {
     ...options,
-    loggingOptions: { logger: options.loggingOptions?.logger ?? logger.info },
+    loggingOptions: {
+      ...options.loggingOptions,
+      logger: options.loggingOptions?.logger ?? logger.info,
+    },
   };
   const clientContext = getClient(endpointUrl, undefined, updatedOptions);
 
@@ -183,12 +186,13 @@ export function _getSend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).get({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     headers: {
       ...(context.expand !== undefined ? { $expand: context.expand } : {}),
       accept: "application/json",
-      ...options.requestOptions?.headers,
+      ...requestParameters.headers,
     },
   });
 }
@@ -359,7 +363,10 @@ export function createBillingBenefits(
   const endpointUrl = options.endpoint ?? String(endpointParam);
   const { apiVersion: _, ...updatedOptions } = {
     ...options,
-    loggingOptions: { logger: options.loggingOptions?.logger ?? logger.info },
+    loggingOptions: {
+      ...options.loggingOptions,
+      logger: options.loggingOptions?.logger ?? logger.info,
+    },
   };
   const clientContext = getClient(endpointUrl, undefined, updatedOptions);
 
@@ -412,12 +419,13 @@ export function _getSend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).get({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     headers: {
       ...(context.expand !== undefined ? { $expand: context.expand } : {}),
       accept: "application/json",
-      ...options.requestOptions?.headers,
+      ...requestParameters.headers,
     },
   });
 }
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/operations/header-param/optionalConstantHeaderParam.md b/packages/typespec-ts/test/modular-unit/scenarios/operations/header-param/optionalConstantHeaderParam.md
index 70d613d770..2047d76762 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/operations/header-param/optionalConstantHeaderParam.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/operations/header-param/optionalConstantHeaderParam.md
@@ -28,8 +28,9 @@ export function _readSend(
   parameters: string,
   options: ReadOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "text/plain",
     headers: {
       "required-header": "requiredValue",
@@ -41,7 +42,7 @@ export function _readSend(
       ...(options?.optionalStringHeader !== undefined
         ? { "optional-string-header": options?.optionalStringHeader }
         : {}),
-      ...options.requestOptions?.headers,
+      ...requestParameters.headers,
     },
     body: parameters,
   });
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/operations/lroPaging.md b/packages/typespec-ts/test/modular-unit/scenarios/operations/lroPaging.md
index 91190f977e..84cb3abae7 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/operations/lroPaging.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/operations/lroPaging.md
@@ -313,9 +313,10 @@ export function _suspendSend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).post({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/operations/operations.md b/packages/typespec-ts/test/modular-unit/scenarios/operations/operations.md
index 43f53b9f89..fd29aad5a9 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/operations/operations.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/operations/operations.md
@@ -151,8 +151,9 @@ export function _readSend(
   prop2: number,
   options: ReadOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "application/json",
     headers: {
       "required-header": requiredHeader,
@@ -195,7 +196,7 @@ export function _readSend(
               : options?.nullableDateHeader.toUTCString(),
           }
         : {}),
-      ...options.requestOptions?.headers,
+      ...requestParameters.headers,
     },
     body: { prop1: prop1, prop2: prop2 },
   });
@@ -266,11 +267,12 @@ export function _readSend(
   nullableRequiredHeader: string | null,
   options: ReadOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").get({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     headers: {
       "nullable-required-header": nullableRequiredHeader,
-      ...options.requestOptions?.headers,
+      ...requestParameters.headers,
     },
   });
 }
@@ -434,9 +436,10 @@ export function _readSend(
   context: Client,
   options: ReadOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
@@ -494,10 +497,11 @@ export function _readSend(
   context: Client,
   options: ReadOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "application/json",
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    headers: { accept: "application/json", ...requestParameters.headers },
     body: !options?.bars ? options?.bars : barArraySerializer(options?.bars),
   });
 }
@@ -615,9 +619,10 @@ export function _readSend(
   context: Client,
   options: ReadOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
@@ -685,9 +690,10 @@ export function _testSend(
   context: Client,
   options: TestOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").post({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
@@ -773,9 +779,10 @@ export function _testSend(
   context: Client,
   options: TestOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").post({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
@@ -875,9 +882,10 @@ export function _getSend(
   context: Client,
   options: GetOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
@@ -969,9 +977,10 @@ export function _getSend(
   context: Client,
   options: GetOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/").get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
@@ -1062,10 +1071,11 @@ export function _createOrUpdateEndpointSend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "application/json",
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    headers: { accept: "application/json", ...requestParameters.headers },
     body: endpointSerializer(endpointParam),
   });
 }
@@ -1196,9 +1206,10 @@ export function _fooSend(
   context: Client,
   options: FooOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/list-post").post({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
@@ -1227,9 +1238,10 @@ export function _barSend(
   context: Client,
   options: BarOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/list-get").post({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/operations/override.md b/packages/typespec-ts/test/modular-unit/scenarios/operations/override.md
index f35bdd6692..66253a2070 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/operations/override.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/operations/override.md
@@ -301,11 +301,12 @@ export function _removeOptionalOriginalSend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).get({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     headers: {
       ...(options?.param4 !== undefined ? { param4: options?.param4 } : {}),
-      ...options.requestOptions?.headers,
+      ...requestParameters.headers,
     },
   });
 }
@@ -415,13 +416,14 @@ export function _changeOptionalityOriginalSend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).get({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     headers: {
       ...(options?.requiredHeader !== undefined
         ? { "required-header": options?.requiredHeader }
         : {}),
-      ...options.requestOptions?.headers,
+      ...requestParameters.headers,
     },
   });
 }
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/operations/pagination/disablePagination.md b/packages/typespec-ts/test/modular-unit/scenarios/operations/pagination/disablePagination.md
index 13549be79b..5d2765be3e 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/operations/pagination/disablePagination.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/operations/pagination/disablePagination.md
@@ -101,9 +101,10 @@ export function _fooSend(
   context: Client,
   options: FooOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/list-post").post({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
@@ -127,9 +128,10 @@ export function _barSend(
   context: Client,
   options: BarOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/list-get").post({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/operations/path-param/pathParamUrlTemplate.md b/packages/typespec-ts/test/modular-unit/scenarios/operations/path-param/pathParamUrlTemplate.md
index 6aa3d2bd80..49594e683a 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/operations/path-param/pathParamUrlTemplate.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/operations/path-param/pathParamUrlTemplate.md
@@ -79,10 +79,11 @@ export function _updateKeySend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).patch({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "text/plain",
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    headers: { accept: "application/json", ...requestParameters.headers },
     body: parameters,
   });
 }
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/operations/path-param/pathParameterNamedPath.md b/packages/typespec-ts/test/modular-unit/scenarios/operations/path-param/pathParameterNamedPath.md
index c998c291fb..6a0cabc2ca 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/operations/path-param/pathParameterNamedPath.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/operations/path-param/pathParameterNamedPath.md
@@ -38,9 +38,10 @@ export function _getResultFileSend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path_1).get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "text/plain", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "text/plain", ...requestParameters.headers },
   });
 }
 ```
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/operations/query-param/queryParamWithClientInitialization.md b/packages/typespec-ts/test/modular-unit/scenarios/operations/query-param/queryParamWithClientInitialization.md
index 86fa2fe1ba..cd7428f72a 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/operations/query-param/queryParamWithClientInitialization.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/operations/query-param/queryParamWithClientInitialization.md
@@ -130,7 +130,10 @@ export function createBillingBenefits(
   const endpointUrl = options.endpoint ?? String(endpointParam);
   const { apiVersion: _, ...updatedOptions } = {
     ...options,
-    loggingOptions: { logger: options.loggingOptions?.logger ?? logger.info },
+    loggingOptions: {
+      ...options.loggingOptions,
+      logger: options.loggingOptions?.logger ?? logger.info,
+    },
   };
   const clientContext = getClient(endpointUrl, undefined, updatedOptions);
 
@@ -184,9 +187,10 @@ export function _getSend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
@@ -356,7 +360,10 @@ export function createBillingBenefits(
   const endpointUrl = options.endpoint ?? String(endpointParam);
   const { apiVersion: _, ...updatedOptions } = {
     ...options,
-    loggingOptions: { logger: options.loggingOptions?.logger ?? logger.info },
+    loggingOptions: {
+      ...options.loggingOptions,
+      logger: options.loggingOptions?.logger ?? logger.info,
+    },
   };
   const clientContext = getClient(endpointUrl, undefined, updatedOptions);
 
@@ -410,9 +417,10 @@ export function _getSend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/operations/wrapNonModelReturn.md b/packages/typespec-ts/test/modular-unit/scenarios/operations/wrapNonModelReturn.md
index 7bd17b6436..47de69474a 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/operations/wrapNonModelReturn.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/operations/wrapNonModelReturn.md
@@ -39,9 +39,10 @@ export function _getSend(
   context: Client,
   options: GetOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/dns").get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "text/plain", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "text/plain", ...requestParameters.headers },
   });
 }
 
@@ -99,9 +100,10 @@ export function _listDomainsSend(
   context: Client,
   options: ListDomainsOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/domains").post({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
@@ -184,9 +186,10 @@ export function _getLogsSend(
   context: Client,
   options: GetLogsOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/logs").get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/octet-stream", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/octet-stream", ...requestParameters.headers },
   });
 }
 
@@ -244,9 +247,10 @@ export function _getSend(
   context: Client,
   options: GetOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/dns").get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "text/plain", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "text/plain", ...requestParameters.headers },
   });
 }
 
@@ -306,9 +310,10 @@ export function _listSend(
   context: Client,
   options: ListOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/resources").get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
@@ -366,9 +371,10 @@ export function _getModelSend(
   context: Client,
   options: GetModelOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/models").get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
@@ -626,9 +632,10 @@ export function _getAnyObjectSend(
   context: Client,
   options: GetAnyObjectOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/anyObject").get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
@@ -655,9 +662,10 @@ export function _getModelArraySend(
   context: Client,
   options: GetModelArrayOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/modelArray").get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
@@ -712,9 +720,10 @@ export function _getAnySend(
   context: Client,
   options: GetAnyOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/any").get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
@@ -739,9 +748,10 @@ export function _getStringArraySend(
   context: Client,
   options: GetStringArrayOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/stringArray").get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "application/json", ...requestParameters.headers },
   });
 }
 
@@ -772,9 +782,10 @@ export function _getBooleanSend(
   context: Client,
   options: GetBooleanOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/boolean").get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "text/plain", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "text/plain", ...requestParameters.headers },
   });
 }
 
@@ -801,9 +812,10 @@ export function _getStringSend(
   context: Client,
   options: GetStringOptionalParams = { requestOptions: {} },
 ): StreamableMethod {
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path("/string").get({
-    ...operationOptionsToRequestParameters(options),
-    headers: { accept: "text/plain", ...options.requestOptions?.headers },
+    ...requestParameters,
+    headers: { accept: "text/plain", ...requestParameters.headers },
   });
 }
 
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/samples/parameters/bodyOptionalCheck.md b/packages/typespec-ts/test/modular-unit/scenarios/samples/parameters/bodyOptionalCheck.md
index 7c07fc941e..d4625300f5 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/samples/parameters/bodyOptionalCheck.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/samples/parameters/bodyOptionalCheck.md
@@ -104,10 +104,11 @@ export function _readSend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "application/json",
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    headers: { accept: "application/json", ...requestParameters.headers },
     body: !options?.widget ? options?.widget : bodyParameterSerializer(options?.widget),
   });
 }
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/samples/parameters/bodyOptionalParameterName.md b/packages/typespec-ts/test/modular-unit/scenarios/samples/parameters/bodyOptionalParameterName.md
index 64c764abc8..ca52269102 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/samples/parameters/bodyOptionalParameterName.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/samples/parameters/bodyOptionalParameterName.md
@@ -167,10 +167,11 @@ export function _backupSend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "application/json",
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    headers: { accept: "application/json", ...requestParameters.headers },
     body: !options?.backupRequestProperties
       ? options?.backupRequestProperties
       : backupRequestPropertiesSerializer(options?.backupRequestProperties),
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/samples/parameters/bodyReadonlyOptionalCheck.md b/packages/typespec-ts/test/modular-unit/scenarios/samples/parameters/bodyReadonlyOptionalCheck.md
index 03e9b293db..37fb0b75e2 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/samples/parameters/bodyReadonlyOptionalCheck.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/samples/parameters/bodyReadonlyOptionalCheck.md
@@ -115,10 +115,11 @@ export function _readSend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "application/json",
-    headers: { accept: "application/json", ...options.requestOptions?.headers },
+    headers: { accept: "application/json", ...requestParameters.headers },
     body: bodyParameterSerializer(widget),
   });
 }
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/samples/parameters/parameterNormalization.md b/packages/typespec-ts/test/modular-unit/scenarios/samples/parameters/parameterNormalization.md
index 18b43b69a3..22119aa3ad 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/samples/parameters/parameterNormalization.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/samples/parameters/parameterNormalization.md
@@ -76,12 +76,13 @@ export function _postSend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "application/json",
     headers: {
       ...(options?.headerParam !== undefined ? { header_param: options?.headerParam } : {}),
-      ...options.requestOptions?.headers,
+      ...requestParameters.headers,
     },
     body: !options?.listCredentialsRequest
       ? options?.listCredentialsRequest
diff --git a/packages/typespec-ts/test/modular-unit/scenarios/samples/parameters/parameterOrdering.md b/packages/typespec-ts/test/modular-unit/scenarios/samples/parameters/parameterOrdering.md
index 4bc2f20e1a..829d161788 100644
--- a/packages/typespec-ts/test/modular-unit/scenarios/samples/parameters/parameterOrdering.md
+++ b/packages/typespec-ts/test/modular-unit/scenarios/samples/parameters/parameterOrdering.md
@@ -96,8 +96,9 @@ export function _verifySend(
       allowReserved: options?.requestOptions?.skipUrlEncoding,
     },
   );
+  const requestParameters = operationOptionsToRequestParameters(options);
   return context.path(path).post({
-    ...operationOptionsToRequestParameters(options),
+    ...requestParameters,
     contentType: "application/json",
     headers: {
       ...(options?.clientRequestId !== undefined
@@ -105,7 +106,7 @@ export function _verifySend(
         : {}),
       "apc-gateway-id": apcGatewayId,
       accept: "application/json",
-      ...options.requestOptions?.headers,
+      ...requestParameters.headers,
     },
     body: testVerificationContentSerializer(body),
   });
diff --git a/packages/typespec-ts/test/util/emit-util.ts b/packages/typespec-ts/test/util/emit-util.ts
index 3759aa0e16..7172d702b8 100644
--- a/packages/typespec-ts/test/util/emit-util.ts
+++ b/packages/typespec-ts/test/util/emit-util.ts
@@ -25,6 +25,7 @@ import { buildRootIndex } from "../../src/modular/build-root-index.js";
 import { buildSubpathIndexFile } from "../../src/modular/build-subpath-index.js";
 import { emitSamples } from "../../src/modular/emit-samples.js";
 import { emitTests } from "../../src/modular/emit-tests.js";
+import { getCredentialInfo } from "../../src/transform/transform-client-options.js";
 import { getClientHierarchyMap } from "../../src/utils/client-utils.js";
 
 export interface ModelConfigOptions extends ClientOptions {
@@ -254,6 +255,16 @@ export async function emitModularClientContextFromTypeSpec(
     withVersionedApiVersion: options.withVersionedApiVersion ? true : false,
   });
   const dpgContext = await createDpgContextTestHelper(context.program);
+  Object.assign(
+    dpgContext.emitterOptions!,
+    getCredentialInfo(dpgContext.program, {
+      "add-credentials": options["add-credentials"],
+      "credential-scopes": options["credential-scopes"],
+      "credential-key-header-name": options["credential-key-header-name"],
+      "custom-http-auth-header-name": options["custom-http-auth-header-name"],
+      "custom-http-auth-shared-key-prefix": options["custom-http-auth-shared-key-prefix"],
+    }),
+  );
   if (options.packageDetails) {
     dpgContext.emitterOptions!.packageDetails = options.packageDetails;
   }