feat: add Anthropic LLM provider

packages/llm/src/providers/anthropic.ts

@@ -0,0 +1,34 @@
+import Anthropic from "@anthropic-ai/sdk";
+import type { LLMMessage, LLMOptions } from "@codeboard/shared";
+import type { LLMProvider } from "./base.js";
+
+export class AnthropicProvider implements LLMProvider {
+  name = "anthropic";
+  private client: Anthropic;
+  private defaultModel: string;
+
+  constructor(apiKey: string, model?: string) {
+    this.client = new Anthropic({ apiKey });
+    this.defaultModel = model ?? "claude-sonnet-4-20250514";
+  }
+
+  async chat(messages: LLMMessage[], options?: LLMOptions): Promise<string> {
+    const systemMessage = messages.find((m) => m.role === "system");
+    const nonSystemMessages = messages
+      .filter((m) => m.role !== "system")
+      .map((m) => ({
+        role: m.role as "user" | "assistant",
+        content: m.content,
+      }));
+
+    const response = await this.client.messages.create({
+      model: options?.model ?? this.defaultModel,
+      max_tokens: options?.maxTokens ?? 4096,
+      system: systemMessage?.content,
+      messages: nonSystemMessages,
+    });
+
+    const textBlock = response.content.find((b) => b.type === "text");
+    return textBlock?.type === "text" ? textBlock.text : "";
+  }
+}