diff --git a/.github/workflows/package-ffi-engine.yml b/.github/workflows/package-ffi-engine.yml
index c238f66b..937438ff 100644
--- a/.github/workflows/package-ffi-engine.yml
+++ b/.github/workflows/package-ffi-engine.yml
@@ -1,7 +1,5 @@
 name: Package FFI Engine
 on:
-  pull_request:
-    branches: ["main"]
   push:
     tags: ["flipt-engine-ffi-v**"]
   workflow_dispatch:
@@ -99,13 +97,6 @@ jobs:
             target/${{ matrix.platform.target }}/release/libfliptengine.* \
             || true
 
-      - name: Upload Artifacts (Pull Request)
-        uses: actions/upload-artifact@v4
-        if: github.event_name == 'pull_request'
-        with:
-          name: flipt-engine-ffi-${{ matrix.platform.name }}
-          path: flipt-engine-ffi-${{ matrix.platform.name }}.tar.gz
-
       - name: Upload Release Assets (Tag)
         uses: softprops/action-gh-release@v2
         if: github.event_name == 'push' && startsWith(github.ref, 'refs/tags/flipt-engine-ffi-v')
diff --git a/flipt-client-browser/README.md b/flipt-client-browser/README.md
index 7d25876b..9e27346e 100644
--- a/flipt-client-browser/README.md
+++ b/flipt-client-browser/README.md
@@ -1,6 +1,5 @@
 # Flipt Client Browser
 
-![Status: Hardening](https://img.shields.io/badge/status-hardening-orange)
 [![npm](https://img.shields.io/npm/v/@flipt-io/flipt-client-browser?label=%40flipt-io%2Fflipt-client-browser)](https://www.npmjs.com/package/@flipt-io/flipt-client-browser)
 
 The `flipt-client-browser` library contains the JavaScript/TypeScript source code for the Flipt [client-side evaluation](https://www.flipt.io/docs/integration/client) client for the browser.
@@ -19,7 +18,7 @@ In your JavaScript/Typescript code you can import this client and use it as so:
 import { FliptEvaluationClient } from '@flipt-io/flipt-client-browser';
 
 // namespace is the first positional argument and is optional here and will have a value of "default" if not specified.
-// engine_opts is the second positional argument and is also optional, the structure is:
+// options is the second positional argument and is also optional, the structure is:
 // {
 //  "url": "http://localhost:8080",
 //  "authentication": {
@@ -46,7 +45,7 @@ console.log(variant);
 The `FliptEvaluationClient` constructor accepts two optional arguments:
 
 - `namespace`: The namespace to fetch flag state from. If not provided, the client will default to the `default` namespace.
-- `engine_opts`: An instance of the `EngineOpts` type that supports several options for the client. The structure is:
+- `options`: An instance of the `ClientOptions` type that supports several options for the client. The structure is:
   - `url`: The URL of the upstream Flipt instance. If not provided, the client will default to `http://localhost:8080`.
   - `authentication`: The authentication strategy to use when communicating with the upstream Flipt instance. If not provided, the client will default to no authentication. See the [Authentication](#authentication) section for more information.
   - `reference`: The [reference](https://docs.flipt.io/guides/user/using-references) to use when fetching flag state. If not provided, reference will not be used.
@@ -80,7 +79,7 @@ The fetcher is a function that takes an optional [`IFetcherOpts`](https://github
 
 ## State Management
 
-The `FliptEvaluationClient` class pulls flag state from the Flipt instance at the `url` provided in the `engine_opts` object on instantiation.
+The `FliptEvaluationClient` class pulls flag state from the Flipt instance at the `url` provided in the `options` object on instantiation.
 
 To update the flag state, you can call the `refresh` method on the `FliptEvaluationClient` class.
 
diff --git a/flipt-client-browser/__tests__/evaluation.test.js b/flipt-client-browser/__tests__/evaluation.test.js
index 6b2a05b0..97bf46d5 100644
--- a/flipt-client-browser/__tests__/evaluation.test.js
+++ b/flipt-client-browser/__tests__/evaluation.test.js
@@ -1,4 +1,5 @@
 const flipt = require('../dist/index.cjs');
+
 describe('FliptEvaluationClient', () => {
   let fliptUrl;
   let authToken;
@@ -32,14 +33,11 @@ describe('FliptEvaluationClient', () => {
       fizz: 'buzz'
     });
 
-    expect(variant.error_message).toBeUndefined();
-    expect(variant.status).toEqual('success');
-    expect(variant.result).toBeDefined();
-    expect(variant.result?.flag_key).toEqual('flag1');
-    expect(variant.result?.match).toEqual(true);
-    expect(variant.result?.reason).toEqual('MATCH_EVALUATION_REASON');
-    expect(variant.result?.segment_keys).toContain('segment1');
-    expect(variant.result?.variant_key).toContain('variant1');
+    expect(variant.flag_key).toEqual('flag1');
+    expect(variant.match).toEqual(true);
+    expect(variant.reason).toEqual('MATCH_EVALUATION_REASON');
+    expect(variant.segment_keys).toContain('segment1');
+    expect(variant.variant_key).toContain('variant1');
   });
 
   test('boolean', () => {
@@ -47,34 +45,26 @@ describe('FliptEvaluationClient', () => {
       fizz: 'buzz'
     });
 
-    expect(boolean.error_message).toBeUndefined();
-    expect(boolean.status).toEqual('success');
-    expect(boolean.result).toBeDefined();
-    expect(boolean.result?.flag_key).toEqual('flag_boolean');
-    expect(boolean.result?.enabled).toEqual(true);
-    expect(boolean.result?.reason).toEqual('MATCH_EVALUATION_REASON');
+    expect(boolean.enabled).toEqual(true);
+    expect(boolean.reason).toEqual('MATCH_EVALUATION_REASON');
   });
 
   test('variant failure', () => {
-    const variant = client.evaluateVariant('nonexistent', 'someentity', {
-      fizz: 'buzz'
-    });
-
-    expect(variant.result).toBeUndefined();
-    expect(variant.status).toEqual('failure');
-    expect(variant.error_message).toEqual(
+    expect(() => {
+      client.evaluateVariant('nonexistent', 'someentity', {
+        fizz: 'buzz'
+      });
+    }).toThrow(
       'invalid request: failed to get flag information default/nonexistent'
     );
   });
 
   test('boolean failure', () => {
-    const boolean = client.evaluateVariant('nonexistent', 'someentity', {
-      fizz: 'buzz'
-    });
-
-    expect(boolean.result).toBeUndefined();
-    expect(boolean.status).toEqual('failure');
-    expect(boolean.error_message).toEqual(
+    expect(() => {
+      client.evaluateVariant('nonexistent', 'someentity', {
+        fizz: 'buzz'
+      });
+    }).toThrow(
       'invalid request: failed to get flag information default/nonexistent'
     );
   });
@@ -86,14 +76,11 @@ describe('FliptEvaluationClient', () => {
       fizz: 'buzz'
     });
 
-    expect(variant.error_message).toBeUndefined();
-    expect(variant.status).toEqual('success');
-    expect(variant.result).toBeDefined();
-    expect(variant.result?.flag_key).toEqual('flag1');
-    expect(variant.result?.match).toEqual(true);
-    expect(variant.result?.reason).toEqual('MATCH_EVALUATION_REASON');
-    expect(variant.result?.segment_keys).toContain('segment1');
-    expect(variant.result?.variant_key).toContain('variant1');
+    expect(variant.flag_key).toEqual('flag1');
+    expect(variant.match).toEqual(true);
+    expect(variant.reason).toEqual('MATCH_EVALUATION_REASON');
+    expect(variant.segment_keys).toContain('segment1');
+    expect(variant.variant_key).toContain('variant1');
   });
 
   test('batch', () => {
@@ -121,12 +108,9 @@ describe('FliptEvaluationClient', () => {
       }
     ]);
 
-    expect(batch.error_message).toBeUndefined();
-    expect(batch.status).toEqual('success');
-    expect(batch.result).toBeDefined();
+    expect(batch.responses).toHaveLength(3);
+    const variant = batch.responses[0];
 
-    expect(batch.result?.responses).toHaveLength(3);
-    const variant = batch.result?.responses[0];
     expect(variant?.type).toEqual('VARIANT_EVALUATION_RESPONSE_TYPE');
     expect(variant?.variant_evaluation_response?.flag_key).toEqual('flag1');
     expect(variant?.variant_evaluation_response?.match).toEqual(true);
@@ -140,7 +124,7 @@ describe('FliptEvaluationClient', () => {
       'variant1'
     );
 
-    const boolean = batch.result?.responses[1];
+    const boolean = batch.responses[1];
     expect(boolean?.type).toEqual('BOOLEAN_EVALUATION_RESPONSE_TYPE');
     expect(boolean?.boolean_evaluation_response?.flag_key).toEqual(
       'flag_boolean'
@@ -150,7 +134,7 @@ describe('FliptEvaluationClient', () => {
       'MATCH_EVALUATION_REASON'
     );
 
-    const error = batch.result?.responses[2];
+    const error = batch.responses[2];
     expect(error?.type).toEqual('ERROR_EVALUATION_RESPONSE_TYPE');
     expect(error?.error_evaluation_response?.flag_key).toEqual('notfound');
     expect(error?.error_evaluation_response?.namespace_key).toEqual('default');
diff --git a/flipt-client-browser/package-lock.json b/flipt-client-browser/package-lock.json
index af6ab1a7..66ec95a7 100644
--- a/flipt-client-browser/package-lock.json
+++ b/flipt-client-browser/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "@flipt-io/flipt-client-browser",
-  "version": "0.0.20",
+  "version": "0.1.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "@flipt-io/flipt-client-browser",
-      "version": "0.0.20",
+      "version": "0.1.0",
       "license": "MIT",
       "devDependencies": {
         "@rollup/plugin-typescript": "^11.1.6",
diff --git a/flipt-client-browser/package.json b/flipt-client-browser/package.json
index ec49a0bf..4162dfa5 100644
--- a/flipt-client-browser/package.json
+++ b/flipt-client-browser/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@flipt-io/flipt-client-browser",
-  "version": "0.0.20",
+  "version": "0.1.0",
   "description": "Flipt Client Evaluation Browser SDK",
   "main": "dist/index.cjs",
   "module": "dist/index.mjs",
diff --git a/flipt-client-browser/src/index.ts b/flipt-client-browser/src/index.ts
index d0ba75c3..1e59a530 100644
--- a/flipt-client-browser/src/index.ts
+++ b/flipt-client-browser/src/index.ts
@@ -2,11 +2,14 @@ import init, { Engine } from '../dist/flipt_engine_wasm.js';
 import wasm from '../dist/flipt_engine_wasm_bg.wasm';
 
 import {
+  BatchEvaluationResponse,
   BatchResult,
+  BooleanEvaluationResponse,
   BooleanResult,
-  EngineOpts,
+  ClientOptions,
   EvaluationRequest,
   IFetcher,
+  VariantEvaluationResponse,
   VariantResult
 } from './models.js';
 
@@ -23,46 +26,46 @@ export class FliptEvaluationClient {
   /**
    * Initialize the client
    * @param namespace - optional namespace to evaluate flags
-   * @param engine_opts - optional engine options
+   * @param options - optional client options
    * @returns {Promise<FliptEvaluationClient>}
    */
   static async init(
     namespace: string = 'default',
-    engine_opts: EngineOpts = {
+    options: ClientOptions = {
       url: 'http://localhost:8080',
       reference: ''
     }
   ): Promise<FliptEvaluationClient> {
     await init(await wasm());
 
-    let url = engine_opts.url ?? 'http://localhost:8080';
+    let url = options.url ?? 'http://localhost:8080';
     // trim trailing slash
     url = url.replace(/\/$/, '');
     url = `${url}/internal/v1/evaluation/snapshot/namespace/${namespace}`;
 
-    if (engine_opts.reference) {
-      url = `${url}?reference=${engine_opts.reference}`;
+    if (options.reference) {
+      url = `${url}?reference=${options.reference}`;
     }
 
     const headers = new Headers();
     headers.append('Accept', 'application/json');
     headers.append('x-flipt-accept-server-version', '1.47.0');
 
-    if (engine_opts.authentication) {
-      if ('client_token' in engine_opts.authentication) {
+    if (options.authentication) {
+      if ('client_token' in options.authentication) {
         headers.append(
           'Authorization',
-          `Bearer ${engine_opts.authentication.client_token}`
+          `Bearer ${options.authentication.client_token}`
         );
-      } else if ('jwt_token' in engine_opts.authentication) {
+      } else if ('jwt_token' in options.authentication) {
         headers.append(
           'Authorization',
-          `JWT ${engine_opts.authentication.jwt_token}`
+          `JWT ${options.authentication.jwt_token}`
         );
       }
     }
 
-    let fetcher = engine_opts.fetcher;
+    let fetcher = options.fetcher;
 
     if (!fetcher) {
       fetcher = async (opts?: { etag?: string }) => {
@@ -126,20 +129,28 @@ export class FliptEvaluationClient {
    * @param flag_key - flag key to evaluate
    * @param entity_id - entity id to evaluate
    * @param context - optional evaluation context
-   * @returns {VariantResult}
+   * @returns {VariantEvaluationResponse}
    */
   public evaluateVariant(
     flag_key: string,
     entity_id: string,
     context: {}
-  ): VariantResult {
+  ): VariantEvaluationResponse {
     const evaluation_request: EvaluationRequest = {
       flag_key,
       entity_id,
       context
     };
 
-    return this.engine.evaluate_variant(evaluation_request) as VariantResult;
+    const result = this.engine.evaluate_variant(
+      evaluation_request
+    ) as VariantResult;
+
+    if (result.status === 'failure') {
+      throw new Error(result.error_message);
+    }
+
+    return result.result as VariantEvaluationResponse;
   }
 
   /**
@@ -147,28 +158,42 @@ export class FliptEvaluationClient {
    * @param flag_key - flag key to evaluate
    * @param entity_id - entity id to evaluate
    * @param context - optional evaluation context
-   * @returns {BooleanResult}
+   * @returns {BooleanEvaluationResponse}
    */
   public evaluateBoolean(
     flag_key: string,
     entity_id: string,
     context: {}
-  ): BooleanResult {
+  ): BooleanEvaluationResponse {
     const evaluation_request: EvaluationRequest = {
       flag_key,
       entity_id,
       context
     };
 
-    return this.engine.evaluate_boolean(evaluation_request) as BooleanResult;
+    const result = this.engine.evaluate_boolean(
+      evaluation_request
+    ) as BooleanResult;
+
+    if (result.status === 'failure') {
+      throw new Error(result.error_message);
+    }
+
+    return result.result as BooleanEvaluationResponse;
   }
 
   /**
    * Evaluate a batch of flag requests
    * @param requests evaluation requests
-   * @returns {BatchResult}
+   * @returns {BatchEvaluationResponse}
    */
-  public evaluateBatch(requests: EvaluationRequest[]): BatchResult {
-    return this.engine.evaluate_batch(requests);
+  public evaluateBatch(requests: EvaluationRequest[]): BatchEvaluationResponse {
+    const result = this.engine.evaluate_batch(requests) as BatchResult;
+
+    if (result.status === 'failure') {
+      throw new Error(result.error_message);
+    }
+
+    return result.result as BatchEvaluationResponse;
   }
 }
diff --git a/flipt-client-browser/src/models.ts b/flipt-client-browser/src/models.ts
index 57ca9ff5..9b3346b3 100644
--- a/flipt-client-browser/src/models.ts
+++ b/flipt-client-browser/src/models.ts
@@ -1,9 +1,9 @@
-export interface IFetcherOpts {
+export interface IFetcherOptions {
   etag?: string;
 }
 
 export interface IFetcher {
-  (opts?: IFetcherOpts): Promise<Response>;
+  (opts?: IFetcherOptions): Promise<Response>;
 }
 
 export interface AuthenticationStrategy {}
@@ -16,7 +16,7 @@ export interface JWTAuthentication extends AuthenticationStrategy {
   jwt_token: string;
 }
 
-export interface EngineOpts {
+export interface ClientOptions {
   url?: string;
   authentication?: AuthenticationStrategy;
   reference?: string;
@@ -34,8 +34,8 @@ export interface VariantEvaluationResponse {
   segment_keys: string[];
   reason: string;
   flag_key: string;
-  variant_key: string;
-  variant_attachment: string;
+  variant_key?: string;
+  variant_attachment?: string;
   request_duration_millis: number;
   timestamp: string;
 }