feat: extend proxy runtime parity

src/server/transformers/anthropic/messages/conversion.test.ts

@@ -524,6 +524,44 @@ describe('convertOpenAiBodyToAnthropicMessagesBody', () => {
     ]);
   });
 
+  it('preserves tool_reference blocks inside tool_result content arrays', () => {
+    const result = sanitizeAnthropicMessagesBody({
+      model: 'claude-opus-4-6',
+      messages: [
+        {
+          role: 'user',
+          content: [
+            {
+              type: 'tool_result',
+              tool_use_id: 'tool_1',
+              content: [
+                { type: 'tool_reference', tool_name: 'lookup' },
+                { type: 'text', text: 'follow-up' },
+              ],
+            },
+          ],
+        },
+      ],
+    });
+
+    expect(result.messages).toEqual([
+      {
+        role: 'user',
+        content: [
+          {
+            type: 'tool_result',
+            tool_use_id: 'tool_1',
+            content: [
+              { type: 'tool_reference', tool_name: 'lookup' },
+              { type: 'text', text: 'follow-up' },
+            ],
+            cache_control: { type: 'ephemeral' },
+          },
+        ],
+      },
+    ]);
+  });
+
   it('adds a second message cache anchor around the 20-block window for long prompts', () => {
     const longContent = Array.from({ length: 25 }, (_, index) => ({
       type: 'text',

src/server/transformers/anthropic/messages/conversion.ts

@@ -187,12 +187,39 @@ function normalizeTextCandidate(value: unknown): string {
   return asTrimmedString(value.text ?? value.content ?? value.output_text);
 }
 
-function normalizeToolMessageContent(raw: unknown): string {
+function sanitizeToolReferenceBlock(item: Record<string, unknown>): Record<string, unknown> | null {
+  const toolName = asTrimmedString(item.tool_name ?? item.toolName ?? item.name);
+  if (!toolName) return null;
+  const next: Record<string, unknown> = {
+    ...item,
+    type: 'tool_reference',
+    tool_name: toolName,
+  };
+  delete next.toolName;
+  if ('name' in next) delete next.name;
+  return next;
+}
+
+function normalizeToolMessageContent(raw: unknown): string | Array<Record<string, unknown>> {
   if (raw === undefined || raw === null) return '';
   if (typeof raw === 'string') return raw;
   if (typeof raw === 'number' || typeof raw === 'boolean') return String(raw);
 
   if (Array.isArray(raw)) {
+    const structuredBlocks = raw
+      .map((item) => {
+        if (typeof item === 'string') return toAnthropicTextBlock(item);
+        if (!isRecord(item)) return null;
+        const type = asTrimmedString(item.type).toLowerCase();
+        if (type === 'tool_reference') return sanitizeToolReferenceBlock(item);
+        if (type === 'text' || type === 'input_text' || type === 'output_text') {
+          return toAnthropicTextBlock(normalizeTextCandidate(item));
+        }
+        return null;
+      })
+      .filter((item): item is Record<string, unknown> => item !== null);
+    if (structuredBlocks.length > 0) return structuredBlocks;
+
     const textParts = raw
       .map((item) => {
         if (typeof item === 'string') return item;
@@ -329,7 +356,7 @@ function sanitizeAnthropicContentBlock(item: Record<string, unknown>): Record<st
   if (type === 'tool_result') {
     const toolUseId = asTrimmedString(item.tool_use_id ?? item.toolUseId);
     const content = normalizeToolMessageContent(item.content ?? item.result);
-    if (!toolUseId || !content) return null;
+    if (!toolUseId || (typeof content === 'string' ? !content : content.length <= 0)) return null;
     const next: Record<string, unknown> = {
       type: 'tool_result',
       tool_use_id: toolUseId,
@@ -355,6 +382,10 @@ function sanitizeAnthropicContentBlock(item: Record<string, unknown>): Record<st
     return next;
   }
 
+  if (type === 'tool_reference') {
+    return sanitizeToolReferenceBlock(item);
+  }
+
   return { ...item };
 }
 
@@ -846,8 +877,11 @@ export function convertOpenAiBodyToAnthropicMessagesBody(
           asTrimmedString(toolCandidate.tool_call_id)
           || asTrimmedString(toolCandidate.id)
         );
-        const toolResultContent = normalizeToolMessageContent(toolCandidate.content).trim();
-        if (toolUseId && toolResultContent) {
+        const toolResultContent = normalizeToolMessageContent(toolCandidate.content);
+        const hasToolResultContent = typeof toolResultContent === 'string'
+          ? toolResultContent.trim().length > 0
+          : toolResultContent.length > 0;
+        if (toolUseId && hasToolResultContent) {
           toolResultBlocks.push({
             type: 'tool_result',
             tool_use_id: toolUseId,