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File Attachments

Last updated January 15, 2026

Send images and PDF documents as part of your message request.

Example request
file-attachment.ts
import Anthropic from '@anthropic-ai/sdk';
import fs from 'node:fs';
 
const apiKey = process.env.AI_GATEWAY_API_KEY || process.env.VERCEL_OIDC_TOKEN;
 
const anthropic = new Anthropic({
  apiKey,
  baseURL: 'https://ai-gateway.vercel.sh',
});
 
// Read files as base64
const pdfData = fs.readFileSync('./document.pdf');
const imageData = fs.readFileSync('./image.png');
 
const pdfBase64 = pdfData.toString('base64');
const imageBase64 = imageData.toString('base64');
 
const message = await anthropic.messages.create({
  model: 'anthropic/claude-sonnet-4.5',
  max_tokens: 1024,
  messages: [
    {
      role: 'user',
      content: [
        {
          type: 'document',
          source: {
            type: 'base64',
            media_type: 'application/pdf',
            data: pdfBase64,
          },
        },
        {
          type: 'image',
          source: {
            type: 'base64',
            media_type: 'image/png',
            data: imageBase64,
          },
        },
        {
          type: 'text',
          text: 'Please summarize the PDF and describe the image.',
        },
      ],
    },
  ],
});
 
console.log('Response:', message.content[0].text);
file-attachment.py
import os
import base64
import anthropic
 
api_key = os.getenv('AI_GATEWAY_API_KEY') or os.getenv('VERCEL_OIDC_TOKEN')
 
client = anthropic.Anthropic(
    api_key=api_key,
    base_url='https://ai-gateway.vercel.sh'
)
 
# Read files as base64
with open('./document.pdf', 'rb') as f:
    pdf_base64 = base64.b64encode(f.read()).decode('utf-8')
 
with open('./image.png', 'rb') as f:
    image_base64 = base64.b64encode(f.read()).decode('utf-8')
 
message = client.messages.create(
    model='anthropic/claude-sonnet-4.5',
    max_tokens=1024,
    messages=[
        {
            'role': 'user',
            'content': [
                {
                    'type': 'document',
                    'source': {
                        'type': 'base64',
                        'media_type': 'application/pdf',
                        'data': pdf_base64,
                    },
                },
                {
                    'type': 'image',
                    'source': {
                        'type': 'base64',
                        'media_type': 'image/png',
                        'data': image_base64,
                    },
                },
                {
                    'type': 'text',
                    'text': 'Please summarize the PDF and describe the image.',
                },
            ],
        }
    ],
)
 
print('Response:', message.content[0].text)
  • Images: image/jpeg, image/png, image/gif, image/webp
  • Documents: application/pdf

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