From fa1db87b74871979f9139e721b476159778e2c37 Mon Sep 17 00:00:00 2001
From: Nicolas Hrubec <nico.hrubec@sentry.io>
Date: Fri, 20 Mar 2026 13:18:46 +0100
Subject: [PATCH 1/7] fix

---
 .../core/src/tracing/ai/messageTruncation.ts  | 76 ++++++++++---------
 packages/core/src/tracing/vercel-ai/index.ts  |  8 ++
 packages/core/src/tracing/vercel-ai/utils.ts  |  1 +
 .../lib/tracing/ai-message-truncation.test.ts | 61 +++++++++++++++
 4 files changed, 112 insertions(+), 34 deletions(-)

diff --git a/packages/core/src/tracing/ai/messageTruncation.ts b/packages/core/src/tracing/ai/messageTruncation.ts
index 16df3c298466..cb1bfb47a4e7 100644
--- a/packages/core/src/tracing/ai/messageTruncation.ts
+++ b/packages/core/src/tracing/ai/messageTruncation.ts
@@ -95,31 +95,36 @@ function truncateTextByBytes(text: string, maxBytes: number): string {
 }
 
 /**
- * Extract text content from a Google GenAI message part.
- * Parts are either plain strings or objects with a text property.
+ * Extract text content from a message part/item.
+ * Handles plain strings and objects with a text property.
  *
  * @returns The text content
  */
-function getPartText(part: TextPart | MediaPart): string {
+function getPartText(part: unknown): string {
   if (typeof part === 'string') {
     return part;
   }
-  if ('text' in part) return part.text;
+  if (typeof part === 'object' && part !== null && 'text' in part && typeof part.text === 'string') {
+    return part.text;
+  }
   return '';
 }
 
 /**
- * Create a new part with updated text content while preserving the original structure.
+ * Create a new part/item with updated text content while preserving the original structure.
  *
  * @param part - Original part (string or object)
  * @param text - New text content
  * @returns New part with updated text
  */
-function withPartText(part: TextPart | MediaPart, text: string): TextPart {
+function withPartText(part: unknown, text: string): unknown {
   if (typeof part === 'string') {
     return text;
   }
-  return { ...part, text };
+  if (typeof part === 'object' && part !== null) {
+    return { ...part, text };
+  }
+  return text;
 }
 
 /**
@@ -176,56 +181,63 @@ function truncateContentMessage(message: ContentMessage, maxBytes: number): unkn
 }
 
 /**
- * Truncate a message with `parts: [...]` format (Google GenAI).
- * Keeps as many complete parts as possible, only truncating the first part if needed.
+ * Truncate a message with an array-based format.
+ * Handles both `parts: [...]` (Google GenAI) and `content: [...]` (OpenAI/Anthropic multimodal).
+ * Keeps as many complete items as possible, only truncating the first item if needed.
  *
- * @param message - Message with parts array
+ * @param message - Message with parts or content array
  * @param maxBytes - Maximum byte limit
  * @returns Array with truncated message, or empty array if it doesn't fit
  */
-function truncatePartsMessage(message: PartsMessage, maxBytes: number): unknown[] {
-  const { parts } = message;
+function truncateArrayMessage(message: PartsMessage | ContentArrayMessage, maxBytes: number): unknown[] {
+  const key = 'parts' in message ? 'parts' : 'content';
+  const rawItems = 'parts' in message ? message.parts : message.content;
+  const items: unknown[] = Array.isArray(rawItems) ? rawItems : [];
 
-  // Calculate overhead by creating empty text parts
-  const emptyParts = parts.map(part => withPartText(part, ''));
-  const overhead = jsonBytes({ ...message, parts: emptyParts });
+  if (items.length === 0) {
+    return [];
+  }
+
+  // Calculate overhead by creating empty text items
+  const emptyItems = items.map(item => withPartText(item, ''));
+  const overhead = jsonBytes({ ...message, [key]: emptyItems });
   let remainingBytes = maxBytes - overhead;
 
   if (remainingBytes <= 0) {
     return [];
   }
 
-  // Include parts until we run out of space
-  const includedParts: (TextPart | MediaPart)[] = [];
+  // Include items until we run out of space
+  const includedItems: unknown[] = [];
 
-  for (const part of parts) {
-    const text = getPartText(part);
+  for (const item of items) {
+    const text = getPartText(item);
     const textSize = utf8Bytes(text);
 
     if (textSize <= remainingBytes) {
-      // Part fits: include it as-is
-      includedParts.push(part);
+      // Item fits: include it as-is
+      includedItems.push(item);
       remainingBytes -= textSize;
-    } else if (includedParts.length === 0) {
-      // First part doesn't fit: truncate it
+    } else if (includedItems.length === 0) {
+      // First item doesn't fit: truncate it
       const truncated = truncateTextByBytes(text, remainingBytes);
       if (truncated) {
-        includedParts.push(withPartText(part, truncated));
+        includedItems.push(withPartText(item, truncated));
       }
       break;
     } else {
-      // Subsequent part doesn't fit: stop here
+      // Subsequent item doesn't fit: stop here
       break;
     }
   }
 
   /* c8 ignore start
    * for type safety only, algorithm guarantees SOME text included */
-  if (includedParts.length <= 0) {
+  if (includedItems.length <= 0) {
     return [];
   } else {
     /* c8 ignore stop */
-    return [{ ...message, parts: includedParts }];
+    return [{ ...message, [key]: includedItems }];
   }
 }
 
@@ -258,13 +270,8 @@ function truncateSingleMessage(message: unknown, maxBytes: number): unknown[] {
     return truncateContentMessage(message, maxBytes);
   }
 
-  if (isContentArrayMessage(message)) {
-    // Content array messages are returned as-is without truncation
-    return [message];
-  }
-
-  if (isPartsMessage(message)) {
-    return truncatePartsMessage(message, maxBytes);
+  if (isContentArrayMessage(message) || isPartsMessage(message)) {
+    return truncateArrayMessage(message, maxBytes);
   }
 
   // Unknown message format: cannot truncate safely
@@ -348,6 +355,7 @@ function truncateMessagesByBytes(messages: unknown[], maxBytes: number): unknown
   const strippedMessage = stripped[0];
 
   // Check if it fits
+  console.log('strippedMessage', strippedMessage);
   const messageBytes = jsonBytes(strippedMessage);
   if (messageBytes <= effectiveMaxBytes) {
     return stripped;
diff --git a/packages/core/src/tracing/vercel-ai/index.ts b/packages/core/src/tracing/vercel-ai/index.ts
index 1d8a27e8e3aa..4cc622730824 100644
--- a/packages/core/src/tracing/vercel-ai/index.ts
+++ b/packages/core/src/tracing/vercel-ai/index.ts
@@ -95,12 +95,15 @@ function mapVercelAiOperationName(operationName: string): string {
  * This is supposed to be used in `client.on('spanStart', ...)
  */
 function onVercelAiSpanStart(span: Span): void {
+  console.log('onVercelAiSpanStart');
   const { data: attributes, description: name } = spanToJSON(span);
 
   if (!name) {
     return;
   }
 
+  console.log('name present', name);
+
   // Tool call spans
   // https://ai-sdk.dev/docs/ai-sdk-core/telemetry#tool-call-spans
   if (attributes[AI_TOOL_CALL_NAME_ATTRIBUTE] && attributes[AI_TOOL_CALL_ID_ATTRIBUTE] && name === 'ai.toolCall') {
@@ -108,6 +111,8 @@ function onVercelAiSpanStart(span: Span): void {
     return;
   }
 
+  console.log('not a tool call')
+
   // V6+ Check if this is a Vercel AI span by checking if the operation ID attribute is present.
   // V5+ Check if this is a Vercel AI span by name pattern.
   if (!attributes[AI_OPERATION_ID_ATTRIBUTE] && !name.startsWith('ai.')) {
@@ -391,6 +396,7 @@ function processToolCallSpan(span: Span, attributes: SpanAttributes): void {
 }
 
 function processGenerateSpan(span: Span, name: string, attributes: SpanAttributes): void {
+  console.log('processGenerateSpan', name);
   span.setAttribute(SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN, 'auto.vercelai.otel');
 
   const nameWthoutAi = name.replace('ai.', '');
@@ -402,7 +408,9 @@ function processGenerateSpan(span: Span, name: string, attributes: SpanAttribute
     span.setAttribute('gen_ai.function_id', functionId);
   }
 
+  console.log('before requestMessagesFromPrompt', attributes);
   requestMessagesFromPrompt(span, attributes);
+  console.log('attributes', attributes);
 
   if (attributes[AI_MODEL_ID_ATTRIBUTE] && !attributes[GEN_AI_RESPONSE_MODEL_ATTRIBUTE]) {
     span.setAttribute(GEN_AI_RESPONSE_MODEL_ATTRIBUTE, attributes[AI_MODEL_ID_ATTRIBUTE]);
diff --git a/packages/core/src/tracing/vercel-ai/utils.ts b/packages/core/src/tracing/vercel-ai/utils.ts
index e72efde75e18..ecf335262ae1 100644
--- a/packages/core/src/tracing/vercel-ai/utils.ts
+++ b/packages/core/src/tracing/vercel-ai/utils.ts
@@ -271,6 +271,7 @@ export function requestMessagesFromPrompt(span: Span, attributes: SpanAttributes
         }
 
         const filteredLength = Array.isArray(filteredMessages) ? filteredMessages.length : 0;
+        console.log('filteredMessages', filteredMessages);
         const truncatedMessages = getTruncatedJsonString(filteredMessages);
 
         span.setAttributes({
diff --git a/packages/core/test/lib/tracing/ai-message-truncation.test.ts b/packages/core/test/lib/tracing/ai-message-truncation.test.ts
index c7f8e0043622..f1f318e02128 100644
--- a/packages/core/test/lib/tracing/ai-message-truncation.test.ts
+++ b/packages/core/test/lib/tracing/ai-message-truncation.test.ts
@@ -547,5 +547,66 @@ describe('message truncation utilities', () => {
         },
       ]);
     });
+
+    it('truncates content array message when first text item does not fit', () => {
+      const messages = [
+        {
+          role: 'user',
+          content: [{ type: 'text', text: `2 ${humongous}` }],
+        },
+      ];
+      const result = truncateGenAiMessages(messages);
+      const truncLen =
+        20_000 -
+        2 -
+        JSON.stringify({
+          role: 'user',
+          content: [{ type: 'text', text: '' }],
+        }).length;
+      expect(result).toStrictEqual([
+        {
+          role: 'user',
+          content: [{ type: 'text', text: `2 ${humongous}`.substring(0, truncLen) }],
+        },
+      ]);
+    });
+
+    it('drops subsequent content array items that do not fit', () => {
+      const messages = [
+        {
+          role: 'assistant',
+          content: [
+            { type: 'text', text: `1 ${big}` },
+            { type: 'image_url', url: 'https://example.com/img.png' },
+            { type: 'text', text: `2 ${big}` },
+            { type: 'text', text: `3 ${big}` },
+            { type: 'text', text: `4 ${giant}` },
+            { type: 'text', text: `5 ${giant}` },
+          ],
+        },
+      ];
+      const result = truncateGenAiMessages(messages);
+      expect(result).toStrictEqual([
+        {
+          role: 'assistant',
+          content: [
+            { type: 'text', text: `1 ${big}` },
+            { type: 'image_url', url: 'https://example.com/img.png' },
+            { type: 'text', text: `2 ${big}` },
+            { type: 'text', text: `3 ${big}` },
+          ],
+        },
+      ]);
+    });
+
+    it('drops content array message if overhead is too large', () => {
+      const messages = [
+        {
+          some_other_field: humongous,
+          content: [{ type: 'text', text: 'hello' }],
+        },
+      ];
+      expect(truncateGenAiMessages(messages)).toStrictEqual([]);
+    });
   });
 });

From 5a0b03b09b1369bba03befce7ac56cc9209fe841 Mon Sep 17 00:00:00 2001
From: Nicolas Hrubec <nico.hrubec@sentry.io>
Date: Fri, 20 Mar 2026 13:37:14 +0100
Subject: [PATCH 2/7] remove consoles

---
 packages/core/src/tracing/ai/messageTruncation.ts | 1 -
 packages/core/src/tracing/vercel-ai/index.ts      | 8 --------
 packages/core/src/tracing/vercel-ai/utils.ts      | 1 -
 3 files changed, 10 deletions(-)

diff --git a/packages/core/src/tracing/ai/messageTruncation.ts b/packages/core/src/tracing/ai/messageTruncation.ts
index cb1bfb47a4e7..4f81662db094 100644
--- a/packages/core/src/tracing/ai/messageTruncation.ts
+++ b/packages/core/src/tracing/ai/messageTruncation.ts
@@ -355,7 +355,6 @@ function truncateMessagesByBytes(messages: unknown[], maxBytes: number): unknown
   const strippedMessage = stripped[0];
 
   // Check if it fits
-  console.log('strippedMessage', strippedMessage);
   const messageBytes = jsonBytes(strippedMessage);
   if (messageBytes <= effectiveMaxBytes) {
     return stripped;
diff --git a/packages/core/src/tracing/vercel-ai/index.ts b/packages/core/src/tracing/vercel-ai/index.ts
index 4cc622730824..1d8a27e8e3aa 100644
--- a/packages/core/src/tracing/vercel-ai/index.ts
+++ b/packages/core/src/tracing/vercel-ai/index.ts
@@ -95,15 +95,12 @@ function mapVercelAiOperationName(operationName: string): string {
  * This is supposed to be used in `client.on('spanStart', ...)
  */
 function onVercelAiSpanStart(span: Span): void {
-  console.log('onVercelAiSpanStart');
   const { data: attributes, description: name } = spanToJSON(span);
 
   if (!name) {
     return;
   }
 
-  console.log('name present', name);
-
   // Tool call spans
   // https://ai-sdk.dev/docs/ai-sdk-core/telemetry#tool-call-spans
   if (attributes[AI_TOOL_CALL_NAME_ATTRIBUTE] && attributes[AI_TOOL_CALL_ID_ATTRIBUTE] && name === 'ai.toolCall') {
@@ -111,8 +108,6 @@ function onVercelAiSpanStart(span: Span): void {
     return;
   }
 
-  console.log('not a tool call')
-
   // V6+ Check if this is a Vercel AI span by checking if the operation ID attribute is present.
   // V5+ Check if this is a Vercel AI span by name pattern.
   if (!attributes[AI_OPERATION_ID_ATTRIBUTE] && !name.startsWith('ai.')) {
@@ -396,7 +391,6 @@ function processToolCallSpan(span: Span, attributes: SpanAttributes): void {
 }
 
 function processGenerateSpan(span: Span, name: string, attributes: SpanAttributes): void {
-  console.log('processGenerateSpan', name);
   span.setAttribute(SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN, 'auto.vercelai.otel');
 
   const nameWthoutAi = name.replace('ai.', '');
@@ -408,9 +402,7 @@ function processGenerateSpan(span: Span, name: string, attributes: SpanAttribute
     span.setAttribute('gen_ai.function_id', functionId);
   }
 
-  console.log('before requestMessagesFromPrompt', attributes);
   requestMessagesFromPrompt(span, attributes);
-  console.log('attributes', attributes);
 
   if (attributes[AI_MODEL_ID_ATTRIBUTE] && !attributes[GEN_AI_RESPONSE_MODEL_ATTRIBUTE]) {
     span.setAttribute(GEN_AI_RESPONSE_MODEL_ATTRIBUTE, attributes[AI_MODEL_ID_ATTRIBUTE]);
diff --git a/packages/core/src/tracing/vercel-ai/utils.ts b/packages/core/src/tracing/vercel-ai/utils.ts
index ecf335262ae1..e72efde75e18 100644
--- a/packages/core/src/tracing/vercel-ai/utils.ts
+++ b/packages/core/src/tracing/vercel-ai/utils.ts
@@ -271,7 +271,6 @@ export function requestMessagesFromPrompt(span: Span, attributes: SpanAttributes
         }
 
         const filteredLength = Array.isArray(filteredMessages) ? filteredMessages.length : 0;
-        console.log('filteredMessages', filteredMessages);
         const truncatedMessages = getTruncatedJsonString(filteredMessages);
 
         span.setAttributes({

From 3069aad595d9fa811c9b41f24bf5c77ed143387f Mon Sep 17 00:00:00 2001
From: Nicolas Hrubec <nico.hrubec@sentry.io>
Date: Fri, 20 Mar 2026 13:42:37 +0100
Subject: [PATCH 3/7] .

---
 .../core/src/tracing/ai/messageTruncation.ts  | 22 ++++++++++---------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/packages/core/src/tracing/ai/messageTruncation.ts b/packages/core/src/tracing/ai/messageTruncation.ts
index 4f81662db094..4c27377cf503 100644
--- a/packages/core/src/tracing/ai/messageTruncation.ts
+++ b/packages/core/src/tracing/ai/messageTruncation.ts
@@ -47,6 +47,11 @@ type MediaPart = {
   content: string;
 };
 
+/**
+ * Union of all item types that can appear in array-based messages.
+ */
+type ArrayMessageItem = TextPart | MediaPart | ContentArrayMessage['content'][number];
+
 /**
  * Calculate the UTF-8 byte length of a string.
  */
@@ -100,11 +105,11 @@ function truncateTextByBytes(text: string, maxBytes: number): string {
  *
  * @returns The text content
  */
-function getPartText(part: unknown): string {
+function getPartText(part: ArrayMessageItem): string {
   if (typeof part === 'string') {
     return part;
   }
-  if (typeof part === 'object' && part !== null && 'text' in part && typeof part.text === 'string') {
+  if ('text' in part && typeof part.text === 'string') {
     return part.text;
   }
   return '';
@@ -117,14 +122,11 @@ function getPartText(part: unknown): string {
  * @param text - New text content
  * @returns New part with updated text
  */
-function withPartText(part: unknown, text: string): unknown {
+function withPartText(part: ArrayMessageItem, text: string): ArrayMessageItem {
   if (typeof part === 'string') {
     return text;
   }
-  if (typeof part === 'object' && part !== null) {
-    return { ...part, text };
-  }
-  return text;
+  return { ...part, text };
 }
 
 /**
@@ -191,8 +193,8 @@ function truncateContentMessage(message: ContentMessage, maxBytes: number): unkn
  */
 function truncateArrayMessage(message: PartsMessage | ContentArrayMessage, maxBytes: number): unknown[] {
   const key = 'parts' in message ? 'parts' : 'content';
-  const rawItems = 'parts' in message ? message.parts : message.content;
-  const items: unknown[] = Array.isArray(rawItems) ? rawItems : [];
+  const items: ArrayMessageItem[] =
+    'parts' in message && Array.isArray(message.parts) ? message.parts : Array.isArray(message.content) ? message.content : [];
 
   if (items.length === 0) {
     return [];
@@ -208,7 +210,7 @@ function truncateArrayMessage(message: PartsMessage | ContentArrayMessage, maxBy
   }
 
   // Include items until we run out of space
-  const includedItems: unknown[] = [];
+  const includedItems: ArrayMessageItem[] = [];
 
   for (const item of items) {
     const text = getPartText(item);

From 1f0a9e8bf4cfddf560097ecfcfdc207fd4c11baa Mon Sep 17 00:00:00 2001
From: Nicolas Hrubec <nico.hrubec@sentry.io>
Date: Fri, 20 Mar 2026 13:47:36 +0100
Subject: [PATCH 4/7] .

---
 .../core/src/tracing/ai/messageTruncation.ts  | 30 +++++++++----------
 1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/packages/core/src/tracing/ai/messageTruncation.ts b/packages/core/src/tracing/ai/messageTruncation.ts
index 4c27377cf503..0792b2ad7799 100644
--- a/packages/core/src/tracing/ai/messageTruncation.ts
+++ b/packages/core/src/tracing/ai/messageTruncation.ts
@@ -100,33 +100,33 @@ function truncateTextByBytes(text: string, maxBytes: number): string {
 }
 
 /**
- * Extract text content from a message part/item.
+ * Extract text content from a message item.
  * Handles plain strings and objects with a text property.
  *
  * @returns The text content
  */
-function getPartText(part: ArrayMessageItem): string {
-  if (typeof part === 'string') {
-    return part;
+function getItemText(item: ArrayMessageItem): string {
+  if (typeof item === 'string') {
+    return item;
   }
-  if ('text' in part && typeof part.text === 'string') {
-    return part.text;
+  if ('text' in item && typeof item.text === 'string') {
+    return item.text;
   }
   return '';
 }
 
 /**
- * Create a new part/item with updated text content while preserving the original structure.
+ * Create a new item with updated text content while preserving the original structure.
  *
- * @param part - Original part (string or object)
+ * @param item - Original item (string or object)
  * @param text - New text content
- * @returns New part with updated text
+ * @returns New item with updated text
  */
-function withPartText(part: ArrayMessageItem, text: string): ArrayMessageItem {
-  if (typeof part === 'string') {
+function withItemText(item: ArrayMessageItem, text: string): ArrayMessageItem {
+  if (typeof item === 'string') {
     return text;
   }
-  return { ...part, text };
+  return { ...item, text };
 }
 
 /**
@@ -201,7 +201,7 @@ function truncateArrayMessage(message: PartsMessage | ContentArrayMessage, maxBy
   }
 
   // Calculate overhead by creating empty text items
-  const emptyItems = items.map(item => withPartText(item, ''));
+  const emptyItems = items.map(item => withItemText(item, ''));
   const overhead = jsonBytes({ ...message, [key]: emptyItems });
   let remainingBytes = maxBytes - overhead;
 
@@ -213,7 +213,7 @@ function truncateArrayMessage(message: PartsMessage | ContentArrayMessage, maxBy
   const includedItems: ArrayMessageItem[] = [];
 
   for (const item of items) {
-    const text = getPartText(item);
+    const text = getItemText(item);
     const textSize = utf8Bytes(text);
 
     if (textSize <= remainingBytes) {
@@ -224,7 +224,7 @@ function truncateArrayMessage(message: PartsMessage | ContentArrayMessage, maxBy
       // First item doesn't fit: truncate it
       const truncated = truncateTextByBytes(text, remainingBytes);
       if (truncated) {
-        includedItems.push(withPartText(item, truncated));
+        includedItems.push(withItemText(item, truncated));
       }
       break;
     } else {

From e5d1ae76b511df423fe57f712b676635981a0a97 Mon Sep 17 00:00:00 2001
From: Nicolas Hrubec <nico.hrubec@sentry.io>
Date: Fri, 20 Mar 2026 13:57:39 +0100
Subject: [PATCH 5/7] readability

---
 .../core/src/tracing/ai/messageTruncation.ts    | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/packages/core/src/tracing/ai/messageTruncation.ts b/packages/core/src/tracing/ai/messageTruncation.ts
index 0792b2ad7799..b758591f32ff 100644
--- a/packages/core/src/tracing/ai/messageTruncation.ts
+++ b/packages/core/src/tracing/ai/messageTruncation.ts
@@ -14,15 +14,20 @@ type ContentMessage = {
   content: string;
 };
 
+/**
+ * One block inside OpenAI / Anthropic `content: [...]` arrays (text, image_url, etc.).
+ */
+type ContentArrayBlock = {
+  [key: string]: unknown;
+  type: string;
+};
+
 /**
  * Message format used by OpenAI and Anthropic APIs for media.
  */
 type ContentArrayMessage = {
   [key: string]: unknown;
-  content: {
-    [key: string]: unknown;
-    type: string;
-  }[];
+  content: ContentArrayBlock[];
 };
 
 /**
@@ -48,9 +53,9 @@ type MediaPart = {
 };
 
 /**
- * Union of all item types that can appear in array-based messages.
+ * One element of an array-based message: OpenAI/Anthropic `content[]` or Google `parts`.
  */
-type ArrayMessageItem = TextPart | MediaPart | ContentArrayMessage['content'][number];
+type ArrayMessageItem = TextPart | MediaPart | ContentArrayBlock;
 
 /**
  * Calculate the UTF-8 byte length of a string.

From e8e454c81df568d5ee45f8b1ff846d6d8b12ed02 Mon Sep 17 00:00:00 2001
From: Nicolas Hrubec <nico.hrubec@sentry.io>
Date: Fri, 20 Mar 2026 14:19:34 +0100
Subject: [PATCH 6/7] .

---
 .../core/src/tracing/ai/messageTruncation.ts  | 23 +++++++++++++++----
 1 file changed, 19 insertions(+), 4 deletions(-)

diff --git a/packages/core/src/tracing/ai/messageTruncation.ts b/packages/core/src/tracing/ai/messageTruncation.ts
index b758591f32ff..f8bc6ae5a202 100644
--- a/packages/core/src/tracing/ai/messageTruncation.ts
+++ b/packages/core/src/tracing/ai/messageTruncation.ts
@@ -187,6 +187,23 @@ function truncateContentMessage(message: ContentMessage, maxBytes: number): unkn
   return [{ ...message, content: truncatedContent }];
 }
 
+/**
+ * Picks content array on the message that should be truncated (`parts` or `content`).
+ * Returns `null` if neither field has a truncateable array.
+ */
+function resolvePartsOrContentForTruncation(message: PartsMessage | ContentArrayMessage): {
+  key: 'parts' | 'content' | null;
+  items: ArrayMessageItem[];
+} {
+  if ('parts' in message && Array.isArray(message.parts)) {
+    return { key: 'parts', items: message.parts };
+  }
+  if ('content' in message && Array.isArray(message.content)) {
+    return { key: 'content', items: message.content };
+  }
+  return { key: null, items: [] };
+}
+
 /**
  * Truncate a message with an array-based format.
  * Handles both `parts: [...]` (Google GenAI) and `content: [...]` (OpenAI/Anthropic multimodal).
@@ -197,11 +214,9 @@ function truncateContentMessage(message: ContentMessage, maxBytes: number): unkn
  * @returns Array with truncated message, or empty array if it doesn't fit
  */
 function truncateArrayMessage(message: PartsMessage | ContentArrayMessage, maxBytes: number): unknown[] {
-  const key = 'parts' in message ? 'parts' : 'content';
-  const items: ArrayMessageItem[] =
-    'parts' in message && Array.isArray(message.parts) ? message.parts : Array.isArray(message.content) ? message.content : [];
+  const { key, items } = resolvePartsOrContentForTruncation(message);
 
-  if (items.length === 0) {
+  if (key === null || items.length === 0) {
     return [];
   }
 

From 52d5b899048595cb935b1a8cf1c730b1165df3d8 Mon Sep 17 00:00:00 2001
From: Nicolas Hrubec <nico.hrubec@sentry.io>
Date: Fri, 20 Mar 2026 14:42:29 +0100
Subject: [PATCH 7/7] rename

---
 packages/core/src/tracing/ai/messageTruncation.ts | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/packages/core/src/tracing/ai/messageTruncation.ts b/packages/core/src/tracing/ai/messageTruncation.ts
index f8bc6ae5a202..779cf332855b 100644
--- a/packages/core/src/tracing/ai/messageTruncation.ts
+++ b/packages/core/src/tracing/ai/messageTruncation.ts
@@ -188,10 +188,10 @@ function truncateContentMessage(message: ContentMessage, maxBytes: number): unkn
 }
 
 /**
- * Picks content array on the message that should be truncated (`parts` or `content`).
- * Returns `null` if neither field has a truncateable array.
+ * Extracts the array items and their key from an array-based message.
+ * Returns `null` key if neither `parts` nor `content` is a valid array.
  */
-function resolvePartsOrContentForTruncation(message: PartsMessage | ContentArrayMessage): {
+function getArrayItems(message: PartsMessage | ContentArrayMessage): {
   key: 'parts' | 'content' | null;
   items: ArrayMessageItem[];
 } {
@@ -214,7 +214,7 @@ function resolvePartsOrContentForTruncation(message: PartsMessage | ContentArray
  * @returns Array with truncated message, or empty array if it doesn't fit
  */
 function truncateArrayMessage(message: PartsMessage | ContentArrayMessage, maxBytes: number): unknown[] {
-  const { key, items } = resolvePartsOrContentForTruncation(message);
+  const { key, items } = getArrayItems(message);
 
   if (key === null || items.length === 0) {
     return [];