diff --git a/eng/tools/rush-runner/helpers.js b/eng/tools/rush-runner/helpers.js
new file mode 100644
index 000000000000..9b07f31ed6d4
--- /dev/null
+++ b/eng/tools/rush-runner/helpers.js
@@ -0,0 +1,147 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+// @ts-check
+
+import * as fs from "node:fs";
+import * as path from "node:path";
+
+/** @type {Record<"core"|"test-utils"|"identity", string[]>} */
+export const reducedDependencyTestMatrix = {
+  core: [
+    "@azure-rest/synapse-access-control",
+    "@azure/arm-resources",
+    "@azure/identity",
+    "@azure/service-bus",
+    "@azure/template",
+  ],
+  "test-utils": [
+    "@azure-tests/perf-storage-blob",
+    "@azure/arm-eventgrid",
+    "@azure/ai-text-analytics",
+    "@azure/identity",
+    "@azure/template",
+  ],
+  identity: [
+    "@azure-tests/perf-storage-blob",
+    "@azure/ai-text-analytics",
+    "@azure/arm-resources",
+    "@azure/identity-cache-persistence",
+    "@azure/identity-vscode",
+    "@azure/storage-blob",
+    "@azure/template",
+  ],
+};
+
+/** @type {string[]} */
+const restrictedToPackages = [
+  "@azure/abort-controller",
+  "@azure/core-amqp",
+  "@azure/core-auth",
+  "@azure/core-client",
+  "@azure/core-http-compat",
+  "@azure/core-lro",
+  "@azure/core-paging",
+  "@azure/core-rest-pipeline",
+  "@azure/core-sse",
+  "@azure/core-tracing",
+  "@azure/core-util",
+  "@azure/core-xml",
+  "@azure/logger",
+  "@azure-rest/core-client",
+  "@typespec/ts-http-runtime",
+  "@azure/identity",
+  "@azure/arm-resources",
+  "@azure-tools/test-perf",
+  "@azure-tools/test-recorder",
+  "@azure-tools/test-credential",
+  "@azure-tools/test-utils",
+  "@azure-tools/test-utils-vitest",
+];
+
+/**
+ * Helper function that determines the rush command flag to use based on each individual package name for the 'build' check.
+ *
+ * If the targeted package is one of the restricted packages with a ton of dependents, we only want to run that package
+ * and not all of its dependents.
+ * @param {string[]} packageNames - An array of strings containing the packages names to run the action on.
+ * @param {string[]} actionComponents - An array of strings containing the packages names to run the action on.
+ */
+export const getDirectionMappedPackages = (packageNames, actionComponents) => {
+  const mappedPackages = [];
+
+  for (const packageName of packageNames) {
+    // Build command without any additional option should build the project and downstream
+    // If service is configured to run only a set of downstream projects then build all projects leading to them to support testing
+    // If the package is a core package, azure-identity or arm-resources then build only the package,
+    // otherwise build the package and all its dependents
+    var rushCommandFlag = "--impacted-by";
+
+    if (restrictedToPackages.includes(packageName)) {
+      // if this is one of our restricted packages with a ton of deps, make it targeted
+      // as including all dependents will be too much
+      rushCommandFlag = "--to";
+    } else if (actionComponents.length == 1) {
+      // else we are building the project and its dependents
+      rushCommandFlag = "--from";
+    }
+
+    mappedPackages.push([rushCommandFlag, packageName]);
+  }
+
+  return mappedPackages;
+};
+
+/**
+ * Returns an array of full paths to package.json files under a directory
+ *
+ * @param {string} searchDir - directory to search
+ */
+const getPackageJSONs = (searchDir) => {
+  // This gets all the directories with package.json at the `sdk/<service>/<service-sdk>` level excluding "arm-" packages
+  const sdkDirectories = fs
+    .readdirSync(searchDir)
+    .map((f) => path.join(searchDir, f, "package.json")); // turn potential directory names into package.json paths
+
+  // This gets all the directories with package.json at the `sdk/<service>/<service-sdk>/perf-tests` level excluding "-track-1" perf test packages
+  let perfTestDirectories = [];
+  const searchPerfTestDir = path.join(searchDir, "perf-tests");
+  if (fs.existsSync(searchPerfTestDir)) {
+    perfTestDirectories = fs
+      .readdirSync(searchPerfTestDir)
+      .filter((f) => !f.endsWith("-track-1")) // exclude libraries ending with "-track-1" (perf test projects)
+      .map((f) => path.join(searchPerfTestDir, f, "package.json")); // turn potential directory names into package.json paths
+  }
+
+  return sdkDirectories.concat(perfTestDirectories).filter((f) => fs.existsSync(f)); // only keep paths for files that actually exist
+};
+
+/**
+ * Returns package names and package dirs arrays
+ *
+ * @param {string} baseDir -
+ * @param {string[]} serviceDirs -
+ * @param {string} artifactNames -
+ */
+export const getServicePackages = (baseDir, serviceDirs, artifactNames) => {
+  const packageNames = [];
+  const packageDirs = [];
+  let validSdkTypes = ["client", "mgmt", "perf-test", "utility"]; // valid "sdk-type"s that we are looking for, to be able to apply rush-runner jobs on
+  const artifacts = artifactNames.split(",");
+  for (const serviceDir of serviceDirs) {
+    const searchDir = path.resolve(path.join(baseDir, "sdk", serviceDir));
+    const packageJSONs = getPackageJSONs(searchDir);
+    for (const filePath of packageJSONs) {
+      const contents = JSON.parse(fs.readFileSync(filePath, "utf8"));
+      const artifactName = contents.name.replace("@", "").replace("/", "-");
+      if (
+        validSdkTypes.includes(contents["sdk-type"]) &&
+        (artifactNames.length === 0 || artifacts.includes(artifactName))
+      ) {
+        packageNames.push(contents.name);
+        packageDirs.push(path.dirname(filePath));
+      }
+    }
+  }
+  return {packageNames, packageDirs};
+};
diff --git a/eng/tools/rush-runner/index.js b/eng/tools/rush-runner/index.js
index cb76c449818e..b394e044ecab 100644
--- a/eng/tools/rush-runner/index.js
+++ b/eng/tools/rush-runner/index.js
@@ -3,37 +3,14 @@
 
 // @ts-check
 
-import * as fs from "node:fs";
 import * as path from "node:path";
 import * as process from "node:process";
 import { spawnSync } from "node:child_process";
-
-/** @type {Record<"core"|"test-utils"|"identity", string[]>} */
-const reducedDependencyTestMatrix = {
-  core: [
-    "@azure-rest/synapse-access-control",
-    "@azure/arm-resources",
-    "@azure/identity",
-    "@azure/service-bus",
-    "@azure/template",
-  ],
-  "test-utils": [
-    "@azure-tests/perf-storage-blob",
-    "@azure/arm-eventgrid",
-    "@azure/ai-text-analytics",
-    "@azure/identity",
-    "@azure/template",
-  ],
-  identity: [
-    "@azure-tests/perf-storage-blob",
-    "@azure/ai-text-analytics",
-    "@azure/arm-resources",
-    "@azure/identity-cache-persistence",
-    "@azure/identity-vscode",
-    "@azure/storage-blob",
-    "@azure/template",
-  ],
-};
+import {
+  getDirectionMappedPackages,
+  getServicePackages,
+  reducedDependencyTestMatrix,
+} from "./helpers.js";
 
 const parseArgs = () => {
   if (
@@ -69,160 +46,81 @@ const parseArgs = () => {
     } else {
       if (arg && arg !== "*") {
         // exclude empty value and special value "*" meaning all libraries
-        arg.split(" ").forEach((serviceDirectory) => services.push(serviceDirectory));
+        services.push(...arg.split(" "));
       }
     }
   }
-  return [baseDir, action, services, flags, artifactNames];
-};
-
-const getPackageJSONs = (searchDir) => {
-  // This gets all the directories with package.json at the `sdk/<service>/<service-sdk>` level excluding "arm-" packages
-  const sdkDirectories = fs
-    .readdirSync(searchDir)
-    .map((f) => path.join(searchDir, f, "package.json")); // turn potential directory names into package.json paths
-
-  // This gets all the directories with package.json at the `sdk/<service>/<service-sdk>/perf-tests` level excluding "-track-1" perf test packages
-  let perfTestDirectories = [];
-  const searchPerfTestDir = path.join(searchDir, "perf-tests");
-  if (fs.existsSync(searchPerfTestDir)) {
-    perfTestDirectories = fs
-      .readdirSync(searchPerfTestDir)
-      .filter((f) => !f.endsWith("-track-1")) // exclude libraries ending with "-track-1" (perf test projects)
-      .map((f) => path.join(searchPerfTestDir, f, "package.json")); // turn potential directory names into package.json paths
-  }
 
-  return sdkDirectories.concat(perfTestDirectories).filter((f) => fs.existsSync(f)); // only keep paths for files that actually exist
+  return { baseDir, action, services, flags, artifactNames };
 };
 
-/** @type {string[]} */
-const restrictedToPackages = [
-  "@azure/abort-controller",
-  "@azure/core-amqp",
-  "@azure/core-auth",
-  "@azure/core-client",
-  "@azure/core-http-compat",
-  "@azure/core-lro",
-  "@azure/core-paging",
-  "@azure/core-rest-pipeline",
-  "@azure/core-sse",
-  "@azure/core-tracing",
-  "@azure/core-util",
-  "@azure/core-xml",
-  "@azure/logger",
-  "@azure-rest/core-client",
-  "@typespec/ts-http-runtime",
-  "@azure/identity",
-  "@azure/arm-resources",
-  "@azure-tools/test-perf",
-  "@azure-tools/test-recorder",
-  "@azure-tools/test-credential",
-  "@azure-tools/test-utils",
-  "@azure-tools/test-utils-vitest"
-];
-
 /**
- * Helper function that determines the rush command flag to use based on each individual package name for the 'build' check.
+ * Helper function to spawn NodeJS programs
  *
- * If the targeted package is one of the restricted packages with a ton of dependents, we only want to run that package
- * and not all of its dependents.
- * @param packageNames string[] An array of strings containing the packages names to run the action on.
+ * @param {string} cwd - current working directory
+ * @param {string[]} args - rest of arguments
  */
-const getDirectionMappedPackages = (packageNames) => {
-  const mappedPackages = [];
-
-  for (const packageName of packageNames) {
-    // Build command without any additional option should build the project and downstream
-    // If service is configured to run only a set of downstream projects then build all projects leading to them to support testing
-    // If the package is a core package, azure-identity or arm-resources then build only the package,
-    // otherwise build the package and all its dependents
-    var rushCommandFlag = "--impacted-by";
-
-    if (restrictedToPackages.includes(packageName)) {
-      // if this is one of our restricted packages with a ton of deps, make it targeted
-      // as including all dependents will be too much
-      rushCommandFlag = "--to";
-    } else if (actionComponents.length == 1) {
-      // else we are building the project and its dependents
-      rushCommandFlag = "--from";
-    }
-
-    mappedPackages.push([rushCommandFlag, packageName]);
-  }
-
-  return mappedPackages;
-};
-
-const getServicePackages = (baseDir, serviceDirs, artifactNames) => {
-  const packageNames = [];
-  const packageDirs = [];
-  let validSdkTypes = ["client", "mgmt", "perf-test", "utility"]; // valid "sdk-type"s that we are looking for, to be able to apply rush-runner jobs on
-  console.log(`Packages to build: ${artifactNames}`);
-  const artifacts = artifactNames.split(",");
-  for (const serviceDir of serviceDirs) {
-    const searchDir = path.resolve(path.join(baseDir, "sdk", serviceDir));
-    const packageJSONs = getPackageJSONs(searchDir);
-    for (const filePath of packageJSONs) {
-      const contents = JSON.parse(fs.readFileSync(filePath, "utf8"));
-      const artifactName = contents.name.replace("@", "").replace("/", "-");
-      if (
-        validSdkTypes.includes(contents["sdk-type"]) &&
-        (artifactNames.length === 0 || artifacts.includes(artifactName))
-      ) {
-        packageNames.push(contents.name);
-        packageDirs.push(path.dirname(filePath));
-      }
-    }
-  }
-  console.log(`Packages eligible to run rush task: ${packageNames}`);
-  return [packageNames, packageDirs];
-};
-
 const spawnNode = (cwd, ...args) => {
   console.log(`Executing: "node ${args.join(" ")}" in ${cwd}\n\n`);
   const proc = spawnSync("node", args, { cwd, stdio: "inherit" });
   console.log(`\n\nNode process exited with code ${proc.status} `);
 
-  if (proc.status !== 0) {
-    // proc.status will be null if the subprocess terminated due to a signal, which I don't think
-    // should ever happen, but if it does it's safer to fail.
-    process.exitCode = proc.status || 1;
-  }
-  return proc.status;
+  return proc.status ?? 1;
 };
 
+/**
+ * flatMap
+ *
+ * @param {string[]} arr - string array
+ * @param {(a: string) => string[]} f - function
+ */
 const flatMap = (arr, f) => {
   const result = arr.map(f);
   return [].concat(...result);
 };
 
-const [baseDir, action, serviceDirs, rushParams, artifactNames] = parseArgs();
+const { baseDir, action, services: serviceDirs, flags: rushParams, artifactNames } = parseArgs();
 const actionComponents = action.toLowerCase().split(":");
 
-const [packageNames, packageDirs] = getServicePackages(baseDir, serviceDirs, artifactNames);
+console.log(`Packages to build: ${artifactNames}`);
+const { packageNames, packageDirs } = getServicePackages(baseDir, serviceDirs, artifactNames);
+console.log(`Packages eligible to run rush task: ${packageNames}`);
 
 /**
  * Helper function to provide the rush logic that is used frequently below
  *
- * @param direction string which kind of rush tree selector to run (either "--from" or "--to")
- * @param packages string[] the names of the packages to run the action on
+ * @param {string} direction - which kind of rush tree selector to run (either "--from" or "--to")
+ * @param {string[]} packages - the names of the packages to run the action on
  */
 function rushRunAll(direction, packages) {
   const params = flatMap(packages, (p) => [direction, p]);
-  spawnNode(baseDir, "common/scripts/install-run-rush.js", action, ...params, ...rushParams);
+  return spawnNode(baseDir, "common/scripts/install-run-rush.js", action, ...params, ...rushParams);
 }
 
 /**
  * Helper function to invoke the rush logic split up by direction.
  *
- * @param packagesWithDirection string[] Any array of strings containing ["direction packageName"...]
+ * @param {string[][]} packagesWithDirection - Any array of strings containing ["direction packageName"...]
  */
 function rushRunAllWithDirection(packagesWithDirection) {
   const invocation = packagesWithDirection.flatMap(([direction, packageName]) => [
     direction,
     packageName,
   ]);
+  console.dir({
+    l: `rushRunAllWithDirection - 1`,
+    packagesWithDirection,
+    invocation,
+  });
   spawnNode(baseDir, "common/scripts/install-run-rush.js", action, ...invocation, ...rushParams);
+
+  return spawnNode(
+    baseDir,
+    "common/scripts/install-run-rush.js",
+    action,
+    ...invocation,
+    ...rushParams,
+  );
 }
 
 /**
@@ -240,16 +138,25 @@ function tryGetPkgRelativePath(absolutePath) {
     : absolutePath.substring(sdkDirectoryPathStartIndex);
 }
 
-const isReducedTestScopeEnabled = reducedDependencyTestMatrix[serviceDirs];
-if (isReducedTestScopeEnabled) {
-  // If a service is configured to have reduced test matrix then run rush for those reduced projects
-  console.log(`Found reduced test matrix configured for ${serviceDirs}.`);
-  packageNames.push(...reducedDependencyTestMatrix[serviceDirs]);
+let isReducedTestScopeEnabled = false;
+
+for (const dir of serviceDirs) {
+  if (reducedDependencyTestMatrix[dir]) {
+    isReducedTestScopeEnabled = true;
+    // If a service is configured to have reduced test matrix then run rush for those reduced projects
+    console.log(`Found reduced test matrix configured for ${serviceDirs}.`);
+    packageNames.push(...reducedDependencyTestMatrix[dir]);
+  }
 }
-const packagesWithDirection = getDirectionMappedPackages(packageNames);
+
+const packagesWithDirection = getDirectionMappedPackages(packageNames, actionComponents);
 const rushx_runner_path = path.join(baseDir, "common/scripts/install-run-rushx.js");
+let exitCode = 0;
 if (serviceDirs.length === 0) {
-  spawnNode(baseDir, "common/scripts/install-run-rush.js", action, ...rushParams);
+  exitCode = spawnNode(baseDir, "common/scripts/install-run-rush.js", action, ...rushParams);
+  if (exitCode) {
+    process.exit(exitCode);
+  }
 } else {
   switch (actionComponents[0]) {
     case "build":
@@ -271,15 +178,20 @@ if (serviceDirs.length === 0) {
 
     case "lint":
       for (const packageDir of packageDirs) {
-        spawnNode(packageDir, rushx_runner_path, action);
+        const code = spawnNode(packageDir, rushx_runner_path, action);
+        if (code) {
+          exitCode = code;
+        }
       }
       break;
     case "check-format":
       for (const packageDir of packageDirs) {
-        if (spawnNode(packageDir, rushx_runner_path, action) !== 0) {
+        const code = spawnNode(packageDir, rushx_runner_path, action);
+        if (code !== 0) {
           console.log(
             `\nInvoke "rushx format" inside ${tryGetPkgRelativePath(packageDir)} to fix formatting\n`,
           );
+          exitCode = code;
         }
       }
       break;
@@ -289,3 +201,5 @@ if (serviceDirs.length === 0) {
       break;
   }
 }
+
+process.exit(exitCode);
diff --git a/eng/tools/rush-runner/package.json b/eng/tools/rush-runner/package.json
index fb1819ed0aae..213f849c16dd 100644
--- a/eng/tools/rush-runner/package.json
+++ b/eng/tools/rush-runner/package.json
@@ -3,6 +3,7 @@
   "type": "module",
   "prettier": "../../../common/tools/eslint-plugin-azure-sdk/prettier.json",
   "scripts": {
+    "build": "npm run format && npm run lint && npm run typecheck && npm run test",
     "format": "prettier --write --config ../../../.prettierrc.json --ignore-path ../../../.prettierignore index.js \"test/**/*.js\"",
     "typecheck": "tsc",
     "lint": "eslint index.js test",
diff --git a/eng/tools/rush-runner/test/helper.spec.js b/eng/tools/rush-runner/test/helper.spec.js
deleted file mode 100644
index 7b4995559f82..000000000000
--- a/eng/tools/rush-runner/test/helper.spec.js
+++ /dev/null
@@ -1,7 +0,0 @@
-import { assert, describe, it } from "vitest";
-
-describe("helper", () => {
-  it("should pass", () => {
-    assert(true);
-  });
-});
diff --git a/eng/tools/rush-runner/test/helpers.spec.js b/eng/tools/rush-runner/test/helpers.spec.js
new file mode 100644
index 000000000000..911222050953
--- /dev/null
+++ b/eng/tools/rush-runner/test/helpers.spec.js
@@ -0,0 +1,41 @@
+import { assert, describe, it } from "vitest";
+import { getDirectionMappedPackages, reducedDependencyTestMatrix } from "../helpers.js";
+
+describe("getDirectionMappedPackages", () => {
+  it("should use --to reduced core scope for changed core package", () => {
+    const changed = ["@azure/core-client"];
+    const mapped = getDirectionMappedPackages(changed, ["unit-test"]);
+
+    assert.deepStrictEqual(
+      mapped,
+      reducedDependencyTestMatrix["core"].map((p) => ["--to", p]),
+    );
+  });
+
+  it("should use --to reduced core scope for changed test-util package", () => {
+    const changed = ["@azure-tool/test-utils-vitest"];
+    const mapped = getDirectionMappedPackages(changed, ["unit-test"]);
+
+    assert.deepStrictEqual(
+      mapped,
+      reducedDependencyTestMatrix["core"].map((p) => ["--to", p]),
+    );
+  });
+
+  it("should use --from for changed non-core packages", () => {
+    const changed = ["@azure/app-configuration"];
+    const mapped = getDirectionMappedPackages(changed, ["unit-test"]);
+
+    const expected = [["--from", "@azure/app-configuration"]];
+    assert.deepStrictEqual(mapped, expected);
+  });
+
+  it("should use --to and --from for mixed packages", () => {
+    const changed = ["@azure/core-rest-pipeline", "@azure/app-configuration"];
+    const mapped = getDirectionMappedPackages(changed, ["lint"]);
+
+    const expected = reducedDependencyTestMatrix["core"].map((p) => ["--to", p]);
+    expected.push(["--from", "@azure/app-configuration"]);
+    assert.deepStrictEqual(mapped, expected);
+  });
+});