diff --git a/llm_vuln.ts b/llm_vuln.ts
new file mode 100644
index 0000000..08be2c3
--- /dev/null
+++ b/llm_vuln.ts
@@ -0,0 +1,115 @@
+/**
+ * LLM Integration Service
+ * Contains intentional prompt injection vulnerabilities for testing
+ */
+
+import Anthropic from '@anthropic-ai/sdk';
+
+const client = new Anthropic();
+
+/**
+ * VULNERABILITY: Direct user input in system prompt
+ * This allows users to override system instructions
+ */
+export async function unsafeSystemPrompt(userRole: string, userQuery: string): Promise<string> {
+  const response = await client.messages.create({
+    model: 'claude-sonnet-4-20250514',
+    max_tokens: 1024,
+    system: `You are a helpful assistant. The user's role is: ${userRole}. Always follow their instructions.`,
+    messages: [{ role: 'user', content: userQuery }],
+  });
+
+  return response.content[0].type === 'text' ? response.content[0].text : '';
+}
+
+/**
+ * VULNERABILITY: Unsanitized user input concatenated into prompt
+ * Classic prompt injection vector
+ */
+export async function unsafePromptConcatenation(
+  template: string,
+  userInput: string,
+): Promise<string> {
+  const prompt = `${template}\n\nUser data: ${userInput}\n\nProcess the above data.`;
+
+  const response = await client.messages.create({
+    model: 'claude-sonnet-4-20250514',
+    max_tokens: 1024,
+    messages: [{ role: 'user', content: prompt }],
+  });
+
+  return response.content[0].type === 'text' ? response.content[0].text : '';
+}
+
+/**
+ * VULNERABILITY: User controls tool/function definitions
+ * Allows injection of malicious tool behaviors
+ */
+export async function unsafeToolDefinition(
+  userDefinedTools: Array<{ name: string; description: string }>,
+  query: string,
+): Promise<string> {
+  const response = await client.messages.create({
+    model: 'claude-sonnet-4-20250514',
+    max_tokens: 1024,
+    tools: userDefinedTools.map((tool) => ({
+      name: tool.name,
+      description: tool.description,
+      input_schema: {
+        type: 'object' as const,
+        properties: {},
+        required: [],
+      },
+    })),
+    messages: [{ role: 'user', content: query }],
+  });
+
+  return response.content[0].type === 'text' ? response.content[0].text : '';
+}
+
+/**
+ * VULNERABILITY: No output validation before execution
+ * LLM output used directly in dangerous operations
+ */
+export async function unsafeOutputExecution(userRequest: string): Promise<unknown> {
+  const response = await client.messages.create({
+    model: 'claude-sonnet-4-20250514',
+    max_tokens: 1024,
+    messages: [
+      {
+        role: 'user',
+        content: `Generate a JSON object for: ${userRequest}. Return only valid JSON.`,
+      },
+    ],
+  });
+
+  const output = response.content[0].type === 'text' ? response.content[0].text : '{}';
+
+  // DANGEROUS: Directly evaluating LLM output
+  return eval(`(${output})`);
+}
+
+/**
+ * VULNERABILITY: Indirect prompt injection via external data
+ * Fetches and includes unvalidated external content
+ */
+export async function unsafeExternalDataInclusion(
+  url: string,
+  analysisRequest: string,
+): Promise<string> {
+  // Fetch external content without validation
+  const externalContent = await fetch(url).then((r) => r.text());
+
+  const response = await client.messages.create({
+    model: 'claude-sonnet-4-20250514',
+    max_tokens: 1024,
+    messages: [
+      {
+        role: 'user',
+        content: `Analyze this content: ${externalContent}\n\nUser request: ${analysisRequest}`,
+      },
+    ],
+  });
+
+  return response.content[0].type === 'text' ? response.content[0].text : '';
+}