diff --git a/e2e/core/node-integration.test.ts b/e2e/core/node-integration.test.ts
index b239791..d86f938 100644
--- a/e2e/core/node-integration.test.ts
+++ b/e2e/core/node-integration.test.ts
@@ -1,4 +1,4 @@
-import { TrackJS, timestamp } from "@trackjs/core";
+import { TrackJS, timestamp, userAgent } from "@trackjs/core";
 import { test, expect, beforeEach } from "vitest";
 import { MockTransport } from "./mocks/transport";
 import type { NetworkTelemetry, Transport, TransportRequest, TransportResponse } from "@trackjs/core";
@@ -49,6 +49,35 @@ test('TrackJS.track() can track errors after install', async () => {
   });
 });
 
+test('TrackJS.track() with environment', async () => {
+  const transport = new MockTransport();
+
+  TrackJS.initialize({
+    token: 'test token',
+    transport,
+    dependencies: {
+      "foo": "1.2.3"
+    },
+    originalUrl: "original-url",
+    referrerUrl: "referrer-url",
+    userAgent: userAgent("Node", "12.1", "windows", "x64", "11.2"),
+  });
+
+  await TrackJS.track(new Error('Oops'));
+
+  expect(transport.sentRequests).toHaveLength(1);
+  expect(JSON.parse(transport.sentRequests[0]?.data as string)).toMatchObject({
+    environment: expect.objectContaining({
+      originalUrl: "original-url",
+      referrer: "referrer-url",
+      dependencies: {
+        "foo": "1.2.3"
+      },
+      userAgent: "Node/12.1 (windows x64 11.2)"
+    })
+  });
+})
+
 test('TrackJS.track() with custom metadata', async () => {
   const transport = new MockTransport();
 
diff --git a/packages/core/package.json b/packages/core/package.json
index 6fe9393..a5c575d 100644
--- a/packages/core/package.json
+++ b/packages/core/package.json
@@ -43,6 +43,6 @@
     "clean": "rimraf dist",
     "prepublishOnly": "npm run build",
     "test": "vitest run",
-    "test:watch": "vitest"
+    "dev": "vitest"
   }
 }
diff --git a/packages/core/src/client.ts b/packages/core/src/client.ts
index ed00ca7..9edccea 100644
--- a/packages/core/src/client.ts
+++ b/packages/core/src/client.ts
@@ -1,7 +1,6 @@
 import { Metadata } from "./metadata";
 import { TelemetryLog } from "./telemetryLog";
 import { timestamp, serialize, isError } from "./utils";
-
 import type {
   CapturePayload,
   Options,
@@ -75,14 +74,12 @@ export class Client {
 
       environment: {
         age: 0,
-        dependencies: {
-          "foo": "bar"
-        },
-        originalUrl: "",
-        referrer: "",
-        userAgent: 'node/22.0 (osx x64 123)',
-        viewportHeight: -1,
-        viewportWidth: -1
+        dependencies: structuredClone(this.options.dependencies),
+        originalUrl: this.options.originalUrl,
+        referrer: this.options.referrerUrl,
+        userAgent: this.options.userAgent,
+        viewportHeight: this.options.viewportHeight,
+        viewportWidth: this.options.viewportWidth
       },
 
       metadata: payloadMetadata.get(),
@@ -92,8 +89,8 @@ export class Client {
       network: this.telemetry.get("net"),
       visitor: this.telemetry.get("vis"),
 
-      agentPlatform: "",
-      version: '0.0.0',
+      agentPlatform: this.options.agent,
+      version: this.options.agentVersion,
       throttled: 0,
     };
   }
diff --git a/packages/core/src/constants.ts b/packages/core/src/constants.ts
new file mode 100644
index 0000000..389c1a6
--- /dev/null
+++ b/packages/core/src/constants.ts
@@ -0,0 +1,6 @@
+export const MAX_METADATA_LENGTH = 500;
+export const MAX_TELEMETRY_LOG_SIZE = 30;
+export const MAX_TELEMETRY_MESSAGE_LENGTH = 10_000;
+export const MAX_TELEMETRY_URI_LENGTH = 1_000;
+export const MAX_TELEMETRY_ATTRIBUTES = 20;
+export const MAX_TELEMETRY_ATTRIBUTE_VALUE = 500;
\ No newline at end of file
diff --git a/packages/core/src/index.ts b/packages/core/src/index.ts
index a95ba72..3e1087e 100644
--- a/packages/core/src/index.ts
+++ b/packages/core/src/index.ts
@@ -1,4 +1,4 @@
 export * as TrackJS from './trackjs';
-export { timestamp, uuid } from './utils/';
+export { timestamp, userAgent, uuid } from './utils/';
 
 export type * from './types/';
\ No newline at end of file
diff --git a/packages/core/src/metadata.ts b/packages/core/src/metadata.ts
index 4ae8d24..a01777e 100644
--- a/packages/core/src/metadata.ts
+++ b/packages/core/src/metadata.ts
@@ -1,7 +1,6 @@
+import { MAX_METADATA_LENGTH } from "./constants";
 import { truncate } from "./utils";
 
-const MAX_METADATA_LENGTH = 500;
-
 export class Metadata {
 
   private store: Map<string, string> = new Map();
@@ -30,9 +29,7 @@ export class Metadata {
 
   public clone(): Metadata {
     const cloned = new Metadata();
-    for (const [key, value] of this.store.entries()) {
-      cloned.store.set(key, value);
-    }
+    cloned.store = structuredClone(this.store);
     return cloned;
   }
 
diff --git a/packages/core/src/telemetryLog.ts b/packages/core/src/telemetryLog.ts
index 31b4e5c..9a0bd30 100644
--- a/packages/core/src/telemetryLog.ts
+++ b/packages/core/src/telemetryLog.ts
@@ -1,11 +1,21 @@
-import type { ConsoleTelemetry, NavigationTelemetry, NetworkTelemetry, Telemetry, TelemetryType, VisitorTelemetry } from "./types";
 import { truncate } from "./utils";
+import {
+  MAX_TELEMETRY_ATTRIBUTE_VALUE,
+  MAX_TELEMETRY_ATTRIBUTES,
+  MAX_TELEMETRY_LOG_SIZE,
+  MAX_TELEMETRY_MESSAGE_LENGTH,
+  MAX_TELEMETRY_URI_LENGTH
+} from "./constants";
+
+import type {
+  ConsoleTelemetry,
+  NavigationTelemetry,
+  NetworkTelemetry,
+  Telemetry,
+  TelemetryType,
+  VisitorTelemetry
+} from "./types";
 
-const MAX_LOG_SIZE = 30;
-const MAX_MESSAGE_LENGTH = 10_000;
-const MAX_URI_LENGTH = 1_000;
-const MAX_ATTRIBUTES = 20;
-const MAX_ATTRIBUTE_VALUE = 500;
 
 export class TelemetryLog {
 
@@ -36,8 +46,8 @@ export class TelemetryLog {
     }
     this.store.push({ type, telemetry});
 
-    if (this.store.length > MAX_LOG_SIZE) {
-      this.store = this.store.slice(this.store.length - MAX_LOG_SIZE);
+    if (this.store.length > MAX_TELEMETRY_LOG_SIZE) {
+      this.store = this.store.slice(this.store.length - MAX_TELEMETRY_LOG_SIZE);
     }
   }
 
@@ -47,7 +57,7 @@ export class TelemetryLog {
 
   public clone(): TelemetryLog {
     const cloned = new TelemetryLog();
-    cloned.store = this.store.slice(0);
+    cloned.store = structuredClone(this.store);
     return cloned;
   }
 
@@ -64,18 +74,18 @@ export class TelemetryLog {
 }
 
 export function _normalizeConsoleTelemetry(telemetry: any) : ConsoleTelemetry {
-  telemetry.message = truncate(telemetry.message, MAX_MESSAGE_LENGTH);
+  telemetry.message = truncate(telemetry.message, MAX_TELEMETRY_MESSAGE_LENGTH);
   return telemetry;
 }
 
 export function _normalizeNavigationTelemetry(telemetry: any) : NavigationTelemetry {
-  telemetry.from = truncate(telemetry.from, MAX_URI_LENGTH);
-  telemetry.to = truncate(telemetry.to, MAX_URI_LENGTH);
+  telemetry.from = truncate(telemetry.from, MAX_TELEMETRY_URI_LENGTH);
+  telemetry.to = truncate(telemetry.to, MAX_TELEMETRY_URI_LENGTH);
   return telemetry;
 }
 
 export function _normalizeNetworkTelemetry(telemetry: any) : NetworkTelemetry {
-  telemetry.url = truncate(telemetry.url, MAX_URI_LENGTH);
+  telemetry.url = truncate(telemetry.url, MAX_TELEMETRY_URI_LENGTH);
   return telemetry;
 }
 
@@ -84,10 +94,10 @@ export function _normalizeVisitorTelemetry(telemetry: any) : VisitorTelemetry {
   const currentAttributes: attributes = telemetry.element?.attributes || {};
   let normalizedAttributes: attributes = {};
 
-  const limitedAttributes = Object.entries(currentAttributes).slice(0, MAX_ATTRIBUTES);
+  const limitedAttributes = Object.entries(currentAttributes).slice(0, MAX_TELEMETRY_ATTRIBUTES);
 
   for (const [key, value] of limitedAttributes) {
-    normalizedAttributes[key] = truncate(value, MAX_ATTRIBUTE_VALUE);
+    normalizedAttributes[key] = truncate(value, MAX_TELEMETRY_ATTRIBUTE_VALUE);
   }
 
   (telemetry.element || {}).attributes = normalizedAttributes;
diff --git a/packages/core/src/trackjs.ts b/packages/core/src/trackjs.ts
index 87caba7..970f3d2 100644
--- a/packages/core/src/trackjs.ts
+++ b/packages/core/src/trackjs.ts
@@ -18,17 +18,25 @@ let config: Options | null = null;
 let client: Client | null = null;
 
 const defaultOptions: Options = {
-  application: '',
+  agent: "core",
+  agentVersion: "{{AGENT_VERSION}}",
+  application: "",
+  dependencies: {},
   correlationId: uuid(),
-  errorURL: 'https://capture.trackjs.com/capture/node',
+  errorURL: "https://capture.trackjs.com/capture/node",
   metadata: {},
   onError: () => true,
+  originalUrl: "",
+  referrerUrl: "",
   serializer: [],
-  sessionId: '',
-  token: '',
+  sessionId: "",
+  token: "",
   transport: new FetchTransport(),
-  userId: '',
-  version: ''
+  userAgent: "",
+  userId: "",
+  version: "",
+  viewportHeight: -1,
+  viewportWidth: -1
 };
 
 /**
@@ -74,7 +82,7 @@ export function initialize(options: Partial<Options> & { token: string }): void
 }
 
 /**
- * Adds a object set of key-value pairs to metadata for any future errors.
+ * Adds a object map of key-value pairs to metadata for any future errors.
  * Keys and values will be truncated to 500 characters.
  *
  * @param metadata - object with string values to be added as metadata.
@@ -163,10 +171,6 @@ export function addTelemetry(type: TelemetryType, telemetry: Telemetry): void {
   return client!.addTelemetry(type, telemetry);
 }
 
-export function addDependencies(...args: [dependencies: Record<string, string>]): void {
-  throw new Error("not implemented");
-}
-
 /**
  * Track and error or error-like object to the TrackJS error monitoring service.
  *
diff --git a/packages/core/src/types/options.ts b/packages/core/src/types/options.ts
index 64fef65..1975213 100644
--- a/packages/core/src/types/options.ts
+++ b/packages/core/src/types/options.ts
@@ -39,6 +39,20 @@ export interface TrackOptions {
 
 export interface Options {
 
+  /**
+   * The name of the TrackJS agent package
+   *
+   * @default "core"
+   */
+  agent: string,
+
+  /**
+   * The version of the TrackJS agent package
+   *
+   * @default "{{AGENT_VERSION}}"
+   */
+  agentVersion: string,
+
   /**
    * TrackJS Application key.
    *
@@ -53,6 +67,14 @@ export interface Options {
    */
   correlationId: string;
 
+  /**
+   * Dependency package names and version for the current environment.
+   *
+   * @default {}
+   * @example { "node": "22.12.0" }
+   */
+  dependencies: { [name: string]: string };
+
   /**
    * URL destination override for capturing errors.
    *
@@ -69,15 +91,32 @@ export interface Options {
 
   /**
    * Custom handler to manipulate or suppress errors captured by the agent.
+   *
    * @param payload error payload to be sent to TrackJS.
    * @returns false will suppress the error from being sent.
-   *
    * @default (payload) => true
    */
   onError: (payload: CapturePayload) => boolean;
 
   /**
-   * Custom functions for serializing objects to strings. Will execute before the default serializer.
+   * When environment has a user interface, the URI location where the application
+   * was started, or the URL of the page when it was first loaded.
+   *
+   * @default ""
+   */
+  originalUrl: string
+
+  /**
+   * When environment has a user interface, the URI location where the user came
+   * from before landing on this page or screen.
+   *
+   * @default ""
+   */
+  referrerUrl: string
+
+  /**
+   * Custom functions for serializing objects to strings. Will execute before the
+   * default serializer.
    *
    * @default []
    */
@@ -96,12 +135,23 @@ export interface Options {
   token: string;
 
   /**
-   * Custom transport function for sending data. Required if the current environment does not support `fetch`.
+   * Custom transport function for sending data. Required if the current
+   * environment does not support `fetch`.
    *
    * @default FetchTransport
    */
   transport: Transport;
 
+  /**
+   * User-Agent string describing the user's running environment, browser, process,
+   * operating system, arch, and version. For non-browser environments, this can
+   * be constructed with the userAgent() util function.
+   *
+   * @see {@link userAgent}
+   * @defaults ""
+   */
+  userAgent: string
+
   /**
    * Customer-generated Id representing the current user.
    *
@@ -116,4 +166,19 @@ export interface Options {
    */
   version: string;
 
+  /**
+   * When environment has a user interface, the height of the user viewport in
+   * pixels.
+   *
+   * @default -1
+   */
+  viewportHeight: number
+
+  /**
+   * When environment has a user interface, the width of the user viewport in
+   * pixels.
+   *
+   * @default -1
+   */
+  viewportWidth: number
 }
\ No newline at end of file
diff --git a/packages/core/src/utils/index.ts b/packages/core/src/utils/index.ts
index 9475c79..97e8a84 100644
--- a/packages/core/src/utils/index.ts
+++ b/packages/core/src/utils/index.ts
@@ -2,4 +2,5 @@ export * from './isType';
 export * from './serialize';
 export * from './timestamp';
 export * from './truncate';
+export * from './userAgent';
 export * from './uuid';
\ No newline at end of file
diff --git a/packages/core/src/utils/userAgent.ts b/packages/core/src/utils/userAgent.ts
new file mode 100644
index 0000000..2ce2b0f
--- /dev/null
+++ b/packages/core/src/utils/userAgent.ts
@@ -0,0 +1,26 @@
+/**
+ * Build a TrackJS-compatible browser-like userAgent string based on the current
+ * running environment.
+ *
+ * @param engine - The runtime engine, like "Node", "Deno", or "Chrome"
+ * @param engineVersion - The runtime version.
+ * @param os - The running operating system, like "Macintosh" or "Windows"
+ * @param osArch - The architecture of the operating system, like "x64"
+ * @param osVersion - The running operating system version, like 10.15.7
+ * @returns A constructed userAgent String
+ *
+ * @example
+ * ```
+ * TrackJS.initialize({
+ *   token: "your-token",
+ *   userAgent: userAgent("Node", "22.12.0", "Macintosh", "x64", "15.6")
+ * })
+ */
+export function userAgent(
+  engine: string,
+  engineVersion: string,
+  os: string,
+  osArch: string,
+  osVersion: string) : string {
+    return `${engine}/${engineVersion.replace("v", "")} (${os} ${osArch} ${osVersion})`;
+}
\ No newline at end of file
diff --git a/packages/core/test/client.test.ts b/packages/core/test/client.test.ts
index ab0d230..80b8695 100644
--- a/packages/core/test/client.test.ts
+++ b/packages/core/test/client.test.ts
@@ -10,17 +10,27 @@ let defaultOptions: Options;
 beforeEach(() => {
   mockTransport = new MockTransport();
   defaultOptions = {
+    agent: "test",
+    agentVersion: "1.2.3",
     application: 'test-app',
     correlationId: 'test-correlation-id',
+    dependencies: {
+      "foo": "1.2.3"
+    },
     errorURL: 'https://test.trackjs.com/capture',
     metadata: {},
     onError: () => true,
+    originalUrl: "original-url",
+    referrerUrl: "referrer-url",
     serializer: [],
     sessionId: 'test-session',
     token: 'test-token',
     transport: mockTransport,
+    userAgent: "test-agent",
     userId: 'test-user',
-    version: '0.0.0'
+    version: '0.0.0',
+    viewportHeight: 100,
+    viewportWidth: 200
   };
 });
 
@@ -54,13 +64,13 @@ describe("_createPayload()", () => {
       environment: {
         age: 0,
         dependencies: {
-          "foo": "bar"
+          "foo": "1.2.3"
         },
-        originalUrl: "",
-        referrer: "",
-        userAgent: 'node/22.0 (osx x64 123)',
-        viewportHeight: -1,
-        viewportWidth: -1
+        originalUrl: "original-url",
+        referrer: "referrer-url",
+        userAgent: "test-agent",
+        viewportHeight: 100,
+        viewportWidth: 200,
       },
 
       metadata: [],
@@ -69,8 +79,8 @@ describe("_createPayload()", () => {
       network: [],
       visitor: [],
 
-      agentPlatform: "",
-      version: '0.0.0',
+      agentPlatform: "test",
+      version: "1.2.3",
       throttled: 0
     });
   });
diff --git a/packages/core/test/utils/userAgent.test.ts b/packages/core/test/utils/userAgent.test.ts
new file mode 100644
index 0000000..a8f90a1
--- /dev/null
+++ b/packages/core/test/utils/userAgent.test.ts
@@ -0,0 +1,7 @@
+import { expect, test } from 'vitest';
+import { userAgent } from '../../src/utils';
+
+test('Constructs expected userAgent String', () => {
+  const result = userAgent("Node", "v22.12.0", "darwin", "arm64", "24.6.0");
+  expect(result).toStrictEqual("Node/22.12.0 (darwin arm64 24.6.0)");
+});