fix: bedrock handle empty content and added max tokens export (#1034)

.changeset/eleven-colts-sniff.md

+---
+"@llamaindex/community": patch
+---
+
+fix: llama3 patched to handle empty content (can happen with system) and added max tokens export

packages/community/src/index.ts

-export { BEDROCK_MODELS, Bedrock } from "./llm/bedrock/base.js";
+export {
+  BEDROCK_MODELS,
+  BEDROCK_MODEL_MAX_TOKENS,
+  Bedrock,
+} from "./llm/bedrock/base.js";

packages/community/src/llm/bedrock/base.ts

@@ -150,6 +150,18 @@ export type BedrockModelParams = {
   maxTokens?: number;
 };
 
+export const BEDROCK_MODEL_MAX_TOKENS: Partial<Record<BEDROCK_MODELS, number>> =
+  {
+    [BEDROCK_MODELS.ANTHROPIC_CLAUDE_3_SONNET]: 4096,
+    [BEDROCK_MODELS.ANTHROPIC_CLAUDE_3_HAIKU]: 4096,
+    [BEDROCK_MODELS.ANTHROPIC_CLAUDE_3_OPUS]: 4096,
+    [BEDROCK_MODELS.ANTHROPIC_CLAUDE_3_5_SONNET]: 4096,
+    [BEDROCK_MODELS.META_LLAMA2_13B_CHAT]: 2048,
+    [BEDROCK_MODELS.META_LLAMA2_70B_CHAT]: 2048,
+    [BEDROCK_MODELS.META_LLAMA3_8B_INSTRUCT]: 2048,
+    [BEDROCK_MODELS.META_LLAMA3_70B_INSTRUCT]: 2048,
+  };
+
 const DEFAULT_BEDROCK_PARAMS = {
   temperature: 0.1,
   topP: 1,

packages/community/src/llm/bedrock/utils.ts

@@ -154,10 +154,10 @@ export const mapChatMessagesToMetaMessages = <T extends ChatMessage>(
   messages: T[],
 ): MetaMessage[] => {
   return messages.map((msg) => {
-    let content: string;
+    let content: string = "";
     if (typeof msg.content === "string") {
       content = msg.content;
-    } else {
+    } else if (msg.content.length) {
       content = (msg.content[0] as MessageContentTextDetail).text;
     }
     return {