diff --git a/packages/core/src/utils/ai/messageTruncation.ts b/packages/core/src/utils/ai/messageTruncation.ts
new file mode 100644
index 000000000000..f72485cd8a40
--- /dev/null
+++ b/packages/core/src/utils/ai/messageTruncation.ts
@@ -0,0 +1,83 @@
+export const DEFAULT_GEN_AI_MESSAGES_BYTE_LIMIT = 20000;
+
+export function getByteSize(str: string): number {
+  let bytes = 0;
+  for (let i = 0; i < str.length; i++) {
+    const code = str.charCodeAt(i);
+    if (code < 0x80) {
+      bytes += 1;
+    } else if (code < 0x800) {
+      bytes += 2;
+    } else if (code < 0xd800 || code >= 0xe000) {
+      bytes += 3;
+    } else {
+      i++;
+      bytes += 4;
+    }
+  }
+  return bytes;
+}
+
+function truncateStringByBytes(str: string, maxBytes: number): string {
+  if (getByteSize(str) <= maxBytes) {
+    return str;
+  }
+
+  let truncatedStr = str;
+  while (getByteSize(truncatedStr) > maxBytes && truncatedStr.length > 0) {
+    truncatedStr = truncatedStr.slice(0, -1);
+  }
+  return truncatedStr;
+}
+
+export function truncateMessagesByBytes(messages: unknown[], maxBytes: number): unknown[] {
+  if (!Array.isArray(messages) || messages.length === 0) {
+    return messages;
+  }
+
+  let currentSize = getByteSize(JSON.stringify(messages));
+
+  if (currentSize <= maxBytes) {
+    return messages;
+  }
+
+  let startIndex = 0;
+
+  while (startIndex < messages.length - 1 && currentSize > maxBytes) {
+    const messageSize = getByteSize(JSON.stringify(messages[startIndex]));
+    currentSize -= messageSize;
+    startIndex++;
+  }
+
+  const remainingMessages = messages.slice(startIndex);
+
+  if (remainingMessages.length === 1) {
+    const singleMessage = remainingMessages[0];
+    const singleMessageSize = getByteSize(JSON.stringify(singleMessage));
+
+    if (singleMessageSize > maxBytes) {
+      if (typeof singleMessage === 'object' && singleMessage !== null && 'content' in singleMessage && typeof (singleMessage as { content: unknown }).content === 'string') {
+        const originalContent = (singleMessage as { content: string }).content;
+        const messageWithoutContent = { ...singleMessage, content: '' };
+        const otherMessagePartsSize = getByteSize(JSON.stringify(messageWithoutContent));
+        const availableContentBytes = maxBytes - otherMessagePartsSize;
+
+        if (availableContentBytes <= 0) {
+          return [];
+        }
+
+        const truncatedContent = truncateStringByBytes(originalContent, availableContentBytes);
+        return [{ ...singleMessage, content: truncatedContent }];
+      } else {
+        return [];
+      }
+    }
+  }
+
+  return remainingMessages;
+}
+
+
+export function truncateGenAiMessages(messages: unknown[]): unknown[] {
+  return truncateMessagesByBytes(messages, DEFAULT_GEN_AI_MESSAGES_BYTE_LIMIT);
+}
diff --git a/packages/core/src/utils/anthropic-ai/index.ts b/packages/core/src/utils/anthropic-ai/index.ts
index 8e77dd76b34e..4dc4df27dcaf 100644
--- a/packages/core/src/utils/anthropic-ai/index.ts
+++ b/packages/core/src/utils/anthropic-ai/index.ts
@@ -23,6 +23,7 @@ import {
   GEN_AI_RESPONSE_TOOL_CALLS_ATTRIBUTE,
   GEN_AI_SYSTEM_ATTRIBUTE,
 } from '../ai/gen-ai-attributes';
+import { truncateGenAiMessages } from '../ai/messageTruncation';
 import { buildMethodPath, getFinalOperationName, getSpanOperation, setTokenUsageAttributes } from '../ai/utils';
 import { handleCallbackErrors } from '../handleCallbackErrors';
 import { instrumentAsyncIterableStream, instrumentMessageStream } from './streaming';
@@ -71,16 +72,24 @@ function extractRequestAttributes(args: unknown[], methodPath: string): Record<s
   return attributes;
 }
 
-/**
- * Add private request attributes to spans.
- * This is only recorded if recordInputs is true.
- */
 function addPrivateRequestAttributes(span: Span, params: Record<string, unknown>): void {
   if ('messages' in params) {
-    span.setAttributes({ [GEN_AI_REQUEST_MESSAGES_ATTRIBUTE]: JSON.stringify(params.messages) });
+    const messages = params.messages;
+    if (Array.isArray(messages)) {
+      const truncatedMessages = truncateGenAiMessages(messages);
+      span.setAttributes({ [GEN_AI_REQUEST_MESSAGES_ATTRIBUTE]: JSON.stringify(truncatedMessages) });
+    } else {
+      span.setAttributes({ [GEN_AI_REQUEST_MESSAGES_ATTRIBUTE]: JSON.stringify(messages) });
+    }
   }
   if ('input' in params) {
-    span.setAttributes({ [GEN_AI_REQUEST_MESSAGES_ATTRIBUTE]: JSON.stringify(params.input) });
+    const input = params.input;
+    if (Array.isArray(input)) {
+      const truncatedInput = truncateGenAiMessages(input);
+      span.setAttributes({ [GEN_AI_REQUEST_MESSAGES_ATTRIBUTE]: JSON.stringify(truncatedInput) });
+    } else {
+      span.setAttributes({ [GEN_AI_REQUEST_MESSAGES_ATTRIBUTE]: JSON.stringify(input) });
+    }
   }
   if ('prompt' in params) {
     span.setAttributes({ [GEN_AI_PROMPT_ATTRIBUTE]: JSON.stringify(params.prompt) });
diff --git a/packages/core/src/utils/google-genai/index.ts b/packages/core/src/utils/google-genai/index.ts
index 20e6e2a53606..610806b52626 100644
--- a/packages/core/src/utils/google-genai/index.ts
+++ b/packages/core/src/utils/google-genai/index.ts
@@ -22,6 +22,7 @@ import {
   GEN_AI_USAGE_OUTPUT_TOKENS_ATTRIBUTE,
   GEN_AI_USAGE_TOTAL_TOKENS_ATTRIBUTE,
 } from '../ai/gen-ai-attributes';
+import { truncateGenAiMessages } from '../ai/messageTruncation';
 import { buildMethodPath, getFinalOperationName, getSpanOperation } from '../ai/utils';
 import { handleCallbackErrors } from '../handleCallbackErrors';
 import { CHAT_PATH, CHATS_CREATE_METHOD, GOOGLE_GENAI_SYSTEM_NAME } from './constants';
@@ -128,25 +129,35 @@ function extractRequestAttributes(
   return attributes;
 }
 
-/**
- * Add private request attributes to spans.
- * This is only recorded if recordInputs is true.
- * Handles different parameter formats for different Google GenAI methods.
- */
 function addPrivateRequestAttributes(span: Span, params: Record<string, unknown>): void {
-  // For models.generateContent: ContentListUnion: Content | Content[] | PartUnion | PartUnion[]
   if ('contents' in params) {
-    span.setAttributes({ [GEN_AI_REQUEST_MESSAGES_ATTRIBUTE]: JSON.stringify(params.contents) });
+    const contents = params.contents;
+    if (Array.isArray(contents)) {
+      const truncatedContents = truncateGenAiMessages(contents);
+      span.setAttributes({ [GEN_AI_REQUEST_MESSAGES_ATTRIBUTE]: JSON.stringify(truncatedContents) });
+    } else {
+      span.setAttributes({ [GEN_AI_REQUEST_MESSAGES_ATTRIBUTE]: JSON.stringify(contents) });
+    }
   }
 
-  // For chat.sendMessage: message can be string or Part[]
   if ('message' in params) {
-    span.setAttributes({ [GEN_AI_REQUEST_MESSAGES_ATTRIBUTE]: JSON.stringify(params.message) });
+    const message = params.message;
+    if (Array.isArray(message)) {
+      const truncatedMessage = truncateGenAiMessages(message);
+      span.setAttributes({ [GEN_AI_REQUEST_MESSAGES_ATTRIBUTE]: JSON.stringify(truncatedMessage) });
+    } else {
+      span.setAttributes({ [GEN_AI_REQUEST_MESSAGES_ATTRIBUTE]: JSON.stringify(message) });
+    }
   }
 
-  // For chats.create: history contains the conversation history
   if ('history' in params) {
-    span.setAttributes({ [GEN_AI_REQUEST_MESSAGES_ATTRIBUTE]: JSON.stringify(params.history) });
+    const history = params.history;
+    if (Array.isArray(history)) {
+      const truncatedHistory = truncateGenAiMessages(history);
+      span.setAttributes({ [GEN_AI_REQUEST_MESSAGES_ATTRIBUTE]: JSON.stringify(truncatedHistory) });
+    } else {
+      span.setAttributes({ [GEN_AI_REQUEST_MESSAGES_ATTRIBUTE]: JSON.stringify(history) });
+    }
   }
 }
 
diff --git a/packages/core/src/utils/openai/index.ts b/packages/core/src/utils/openai/index.ts
index 4ecfad625062..7613dde5038b 100644
--- a/packages/core/src/utils/openai/index.ts
+++ b/packages/core/src/utils/openai/index.ts
@@ -19,6 +19,7 @@ import {
   GEN_AI_RESPONSE_TOOL_CALLS_ATTRIBUTE,
   GEN_AI_SYSTEM_ATTRIBUTE,
 } from '../ai/gen-ai-attributes';
+import { truncateGenAiMessages } from '../ai/messageTruncation';
 import { OPENAI_INTEGRATION_NAME } from './constants';
 import { instrumentStream } from './streaming';
 import type {
@@ -188,13 +189,24 @@ function addResponseAttributes(span: Span, result: unknown, recordOutputs?: bool
   }
 }
 
-// Extract and record AI request inputs, if present. This is intentionally separate from response attributes.
 function addRequestAttributes(span: Span, params: Record<string, unknown>): void {
   if ('messages' in params) {
-    span.setAttributes({ [GEN_AI_REQUEST_MESSAGES_ATTRIBUTE]: JSON.stringify(params.messages) });
+    const messages = params.messages;
+    if (Array.isArray(messages)) {
+      const truncatedMessages = truncateGenAiMessages(messages);
+      span.setAttributes({ [GEN_AI_REQUEST_MESSAGES_ATTRIBUTE]: JSON.stringify(truncatedMessages) });
+    } else {
+      span.setAttributes({ [GEN_AI_REQUEST_MESSAGES_ATTRIBUTE]: JSON.stringify(messages) });
+    }
   }
   if ('input' in params) {
-    span.setAttributes({ [GEN_AI_REQUEST_MESSAGES_ATTRIBUTE]: JSON.stringify(params.input) });
+    const input = params.input;
+    if (Array.isArray(input)) {
+      const truncatedInput = truncateGenAiMessages(input);
+      span.setAttributes({ [GEN_AI_REQUEST_MESSAGES_ATTRIBUTE]: JSON.stringify(truncatedInput) });
+    } else {
+      span.setAttributes({ [GEN_AI_REQUEST_MESSAGES_ATTRIBUTE]: JSON.stringify(input) });
+    }
   }
 }
 
diff --git a/packages/core/src/utils/vercel-ai/index.ts b/packages/core/src/utils/vercel-ai/index.ts
index 9b1cc2bc8aae..238ba845f918 100644
--- a/packages/core/src/utils/vercel-ai/index.ts
+++ b/packages/core/src/utils/vercel-ai/index.ts
@@ -3,6 +3,7 @@ import { SEMANTIC_ATTRIBUTE_SENTRY_OP, SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN } from '
 import type { Event } from '../../types-hoist/event';
 import type { Span, SpanAttributes, SpanAttributeValue, SpanJSON, SpanOrigin } from '../../types-hoist/span';
 import { spanToJSON } from '../spanUtils';
+import { truncateGenAiMessages } from '../ai/messageTruncation';
 import { toolCallSpanMap } from './constants';
 import type { TokenSummary } from './types';
 import { accumulateTokensForParent, applyAccumulatedTokens } from './utils';
@@ -190,7 +191,13 @@ function processGenerateSpan(span: Span, name: string, attributes: SpanAttribute
   }
 
   if (attributes[AI_PROMPT_ATTRIBUTE]) {
-    span.setAttribute('gen_ai.prompt', attributes[AI_PROMPT_ATTRIBUTE]);
+    const prompt = attributes[AI_PROMPT_ATTRIBUTE];
+    if (Array.isArray(prompt)) {
+      const truncatedPrompt = truncateGenAiMessages(prompt);
+      span.setAttribute('gen_ai.prompt', JSON.stringify(truncatedPrompt));
+    } else {
+      span.setAttribute('gen_ai.prompt', prompt);
+    }
   }
   if (attributes[AI_MODEL_ID_ATTRIBUTE] && !attributes[GEN_AI_RESPONSE_MODEL_ATTRIBUTE]) {
     span.setAttribute(GEN_AI_RESPONSE_MODEL_ATTRIBUTE, attributes[AI_MODEL_ID_ATTRIBUTE]);