diff --git a/core/llm/llms/HuggingFaceInferenceAPI.ts b/core/llm/llms/HuggingFaceInferenceAPI.ts
index 208f6fd495d..3d0fb801c20 100644
--- a/core/llm/llms/HuggingFaceInferenceAPI.ts
+++ b/core/llm/llms/HuggingFaceInferenceAPI.ts
@@ -3,6 +3,7 @@ import { CompletionOptions } from "../../index.js";
 import { BaseLLM } from "../index.js";
 
 class HuggingFaceInferenceAPI extends BaseLLM {
+  private static MAX_STOP_TOKENS = 4;
   static providerName = "huggingface-inference-api";
 
   private _convertArgs(options: CompletionOptions) {
@@ -11,6 +12,10 @@ class HuggingFaceInferenceAPI extends BaseLLM {
       temperature: options.temperature,
       top_k: options.topK,
       top_p: options.topP,
+      stop: options.stop?.slice(
+        0,
+        this.maxStopWords ?? HuggingFaceInferenceAPI.MAX_STOP_TOKENS,
+      ),
     };
   }
 
diff --git a/core/llm/llms/HuggingFaceInferenceAPI.vitest.ts b/core/llm/llms/HuggingFaceInferenceAPI.vitest.ts
new file mode 100644
index 00000000000..cfe99c2de1e
--- /dev/null
+++ b/core/llm/llms/HuggingFaceInferenceAPI.vitest.ts
@@ -0,0 +1,230 @@
+import { afterEach, describe, expect, test, vi } from "vitest";
+import { ILLM } from "../../index.js";
+import HuggingFaceInferenceAPI from "./HuggingFaceInferenceAPI.js";
+
+interface LlmTestCase {
+  llm: ILLM;
+  methodToTest: keyof ILLM;
+  params: any[];
+  expectedRequest: {
+    url: string;
+    method: string;
+    headers?: Record<string, string>;
+    body?: Record<string, any>;
+  };
+  mockResponse?: any;
+  mockStream?: any[];
+}
+
+function createMockStream(mockStream: any[]) {
+  const encoder = new TextEncoder();
+  return new ReadableStream({
+    start(controller) {
+      for (const chunk of mockStream) {
+        controller.enqueue(
+          encoder.encode(
+            `data: ${
+              typeof chunk === "string" ? chunk : JSON.stringify(chunk)
+            }\n\n`,
+          ),
+        );
+      }
+      controller.close();
+    },
+  });
+}
+
+function setupMockFetch(mockResponse?: any, mockStream?: any[]) {
+  const mockFetch = vi.fn();
+
+  if (mockStream) {
+    const stream = createMockStream(mockStream);
+    mockFetch.mockResolvedValue(
+      new Response(stream, {
+        headers: {
+          "Content-Type": "text/event-stream",
+        },
+      }),
+    );
+  } else {
+    mockFetch.mockResolvedValue(
+      new Response(JSON.stringify(mockResponse), {
+        headers: { "Content-Type": "application/json" },
+      }),
+    );
+  }
+
+  return mockFetch;
+}
+
+function setupReadableStreamPolyfill() {
+  // This can be removed if https://github.com/nodejs/undici/issues/2888 is resolved
+  // @ts-ignore
+  const originalFrom = ReadableStream.from;
+  // @ts-ignore
+  ReadableStream.from = (body) => {
+    if (body?.source) {
+      return body;
+    }
+    return originalFrom(body);
+  };
+}
+
+async function executeLlmMethod(
+  llm: ILLM,
+  methodToTest: keyof ILLM,
+  params: any[],
+) {
+  if (typeof (llm as any)[methodToTest] !== "function") {
+    throw new Error(
+      `Method ${String(methodToTest)} does not exist on the LLM instance.`,
+    );
+  }
+
+  const result = await (llm as any)[methodToTest](...params);
+  if (result?.next) {
+    for await (const _ of result) {
+    }
+  }
+}
+
+function assertFetchCall(mockFetch: any, expectedRequest: any) {
+  expect(mockFetch).toHaveBeenCalledTimes(1);
+  const [url, options] = mockFetch.mock.calls[0];
+
+  expect(url.toString()).toBe(expectedRequest.url);
+  expect(options.method).toBe(expectedRequest.method);
+
+  if (expectedRequest.headers) {
+    expect(options.headers).toEqual(
+      expect.objectContaining(expectedRequest.headers),
+    );
+  }
+
+  if (expectedRequest.body) {
+    const actualBody = JSON.parse(options.body as string);
+    expect(actualBody).toEqual(expectedRequest.body);
+  }
+}
+
+async function runLlmTest(testCase: LlmTestCase) {
+  const {
+    llm,
+    methodToTest,
+    params,
+    expectedRequest,
+    mockResponse,
+    mockStream,
+  } = testCase;
+
+  const mockFetch = setupMockFetch(mockResponse, mockStream);
+  setupReadableStreamPolyfill();
+
+  (llm as any).fetch = mockFetch;
+
+  await executeLlmMethod(llm, methodToTest, params);
+  assertFetchCall(mockFetch, expectedRequest);
+}
+
+describe("HuggingFaceInferenceAPI", () => {
+  afterEach(() => {
+    vi.clearAllMocks();
+  });
+
+  test("streamComplete should forward stop sequences", async () => {
+    const hf = new HuggingFaceInferenceAPI({
+      apiKey: "test-api-key",
+      model: "bigcode/starcoder2-3b",
+      apiBase: "https://example.endpoints.huggingface.cloud",
+    });
+
+    await runLlmTest({
+      llm: hf,
+      methodToTest: "streamComplete",
+      params: [
+        "def add(a, b): return ",
+        new AbortController().signal,
+        { raw: true, maxTokens: 1024, stop: ["<|endoftext|>", "<fim_prefix>"] },
+      ],
+      expectedRequest: {
+        url: "https://example.endpoints.huggingface.cloud/",
+        method: "POST",
+        headers: {
+          Authorization: "Bearer test-api-key",
+          "Content-Type": "application/json",
+        },
+        body: {
+          inputs: "def add(a, b): return ",
+          stream: true,
+          parameters: {
+            max_new_tokens: 1024,
+            stop: ["<|endoftext|>", "<fim_prefix>"],
+          },
+        },
+      },
+      mockStream: [{ token: { text: "a + b" } }],
+    });
+  });
+
+  test("streamComplete should cap stop sequences at maxStopWords", async () => {
+    const hf = new HuggingFaceInferenceAPI({
+      apiKey: "test-api-key",
+      model: "bigcode/starcoder2-3b",
+      apiBase: "https://example.endpoints.huggingface.cloud",
+      maxStopWords: 2,
+    });
+
+    await runLlmTest({
+      llm: hf,
+      methodToTest: "streamComplete",
+      params: [
+        "hello",
+        new AbortController().signal,
+        { raw: true, maxTokens: 1024, stop: ["a", "b", "c", "d"] },
+      ],
+      expectedRequest: {
+        url: "https://example.endpoints.huggingface.cloud/",
+        method: "POST",
+        body: {
+          inputs: "hello",
+          stream: true,
+          parameters: {
+            max_new_tokens: 1024,
+            stop: ["a", "b"],
+          },
+        },
+      },
+      mockStream: [{ token: { text: "ok" } }],
+    });
+  });
+
+  test("streamComplete should omit stop when none are given", async () => {
+    const hf = new HuggingFaceInferenceAPI({
+      apiKey: "test-api-key",
+      model: "bigcode/starcoder2-3b",
+      apiBase: "https://example.endpoints.huggingface.cloud",
+    });
+
+    await runLlmTest({
+      llm: hf,
+      methodToTest: "streamComplete",
+      params: [
+        "hello",
+        new AbortController().signal,
+        { raw: true, maxTokens: 1024 },
+      ],
+      expectedRequest: {
+        url: "https://example.endpoints.huggingface.cloud/",
+        method: "POST",
+        body: {
+          inputs: "hello",
+          stream: true,
+          parameters: {
+            max_new_tokens: 1024,
+          },
+        },
+      },
+      mockStream: [{ token: { text: "ok" } }],
+    });
+  });
+});