fix: support input_file for chat completions when possible (#735)

Co-authored-by: Kazuhiro Sera <seratch@openai.com>

Author: danielmklein

.changeset/sharp-towns-cheer.md

@@ -0,0 +1,5 @@
+---
+'@openai/agents-openai': patch
+---
+
+fix: support input_file for chat completions when possible

packages/agents-openai/src/openaiChatCompletionsConverter.ts

@@ -96,11 +96,40 @@ export function extractAllUserContent(
         ...rest,
       });
     } else if (c.type === 'input_file') {
-      throw new Error(
-        `File uploads are not supported for chat completions: ${JSON.stringify(
-          c,
-        )}`,
-      );
+      // Chat Completions API supports file inputs via the "file" content part type.
+      // See: https://platform.openai.com/docs/guides/pdf-files?api-mode=chat
+      const file: ChatCompletionContentPart.File['file'] = {};
+
+      if (typeof c.file === 'string') {
+        const value = c.file.trim();
+        if (value.startsWith('data:')) {
+          file.file_data = value;
+        } else {
+          throw new UserError(
+            `Chat Completions only supports data URLs for file input. If you're trying to pass an uploaded file's ID, use an object with the id property instead: ${JSON.stringify(c)}`,
+          );
+        }
+      } else if (c.file && typeof c.file === 'object' && 'id' in c.file) {
+        file.file_id = (c.file as { id: string }).id;
+      } else {
+        throw new UserError(
+          `File input requires a data URL or file ID: ${JSON.stringify(c)}`,
+        );
+      }
+
+      // Handle filename from the content item or providerData
+      if (c.filename) {
+        file.filename = c.filename;
+      } else if (c.providerData?.filename) {
+        file.filename = c.providerData.filename;
+      }
+
+      const { filename: _filename, ...rest } = c.providerData || {};
+      out.push({
+        type: 'file',
+        file,
+        ...rest,
+      });
     } else if (c.type === 'audio') {
       const { input_audio, ...rest } = c.providerData || {};
       out.push({

packages/agents-openai/test/openaiChatCompletionsConverter.test.ts

@@ -87,6 +87,136 @@ describe('content extraction helpers', () => {
     expect(() => extractAllUserContent(bad)).toThrow();
   });
 
+  test('extractAllUserContent converts input_file with data URL', () => {
+    const userContent: protocol.UserMessageItem['content'] = [
+      {
+        type: 'input_file',
+        file: 'data:application/pdf;base64,JVBER...',
+        filename: 'document.pdf',
+      },
+    ];
+    const converted = extractAllUserContent(userContent);
+    expect(converted).toEqual([
+      {
+        type: 'file',
+        file: {
+          file_data: 'data:application/pdf;base64,JVBER...',
+          filename: 'document.pdf',
+        },
+      },
+    ]);
+  });
+
+  test('extractAllUserContent throws on https URL (not supported in Chat Completions)', () => {
+    const userContent: protocol.UserMessageItem['content'] = [
+      {
+        type: 'input_file',
+        file: 'https://example.com/document.pdf',
+      },
+    ];
+    expect(() => extractAllUserContent(userContent)).toThrow(
+      /Chat Completions only supports data URLs/,
+    );
+  });
+
+  test('extractAllUserContent converts input_file with file ID object', () => {
+    const userContent: protocol.UserMessageItem['content'] = [
+      {
+        type: 'input_file',
+        file: { id: 'file-abc123' },
+      },
+    ];
+    const converted = extractAllUserContent(userContent);
+    expect(converted).toEqual([
+      {
+        type: 'file',
+        file: {
+          file_id: 'file-abc123',
+        },
+      },
+    ]);
+  });
+
+  test('extractAllUserContent throws on file URL object (not supported in Chat Completions)', () => {
+    const userContent: protocol.UserMessageItem['content'] = [
+      {
+        type: 'input_file',
+        file: { url: 'https://example.com/document.pdf' },
+      },
+    ];
+    expect(() => extractAllUserContent(userContent)).toThrow(
+      /requires a data URL or file ID/,
+    );
+  });
+
+  test('extractAllUserContent gets filename from providerData', () => {
+    const userContent: protocol.UserMessageItem['content'] = [
+      {
+        type: 'input_file',
+        file: 'data:application/pdf;base64,JVBER...',
+        providerData: {
+          filename: 'from-provider.pdf',
+        },
+      },
+    ];
+    const converted = extractAllUserContent(userContent);
+    expect(converted).toEqual([
+      {
+        type: 'file',
+        file: {
+          file_data: 'data:application/pdf;base64,JVBER...',
+          filename: 'from-provider.pdf',
+        },
+      },
+    ]);
+  });
+
+  test('extractAllUserContent prefers content filename over providerData', () => {
+    const userContent: protocol.UserMessageItem['content'] = [
+      {
+        type: 'input_file',
+        file: 'data:application/pdf;base64,JVBER...',
+        filename: 'content-filename.pdf',
+        providerData: {
+          filename: 'from-provider.pdf',
+        },
+      },
+    ];
+    const converted = extractAllUserContent(userContent);
+    expect(converted).toEqual([
+      {
+        type: 'file',
+        file: {
+          file_data: 'data:application/pdf;base64,JVBER...',
+          filename: 'content-filename.pdf',
+        },
+      },
+    ]);
+  });
+
+  test('extractAllUserContent throws on unsupported file string format', () => {
+    const userContent: protocol.UserMessageItem['content'] = [
+      {
+        type: 'input_file',
+        file: 'not-a-valid-url-or-data',
+      },
+    ];
+    expect(() => extractAllUserContent(userContent)).toThrow(
+      /use an object with the id property/,
+    );
+  });
+
+  test('extractAllUserContent throws when file is missing', () => {
+    const userContent: protocol.UserMessageItem['content'] = [
+      {
+        type: 'input_file',
+      },
+    ];
+    expect(() => extractAllUserContent(userContent)).toThrow(
+      /requires a data URL or file ID/,
+    );
+  });
+
   test('extractAllAssistantContent converts supported entries and ignores images/audio', () => {
     const assistantContent: protocol.AssistantMessageItem['content'] = [
       { type: 'output_text', text: 'hi', providerData: { b: 2 } },