Documents and PDFs

Messages API accepts Anthropic-style document blocks for PDFs and text-like document content. Use this when your existing Anthropic-style client already works with document blocks and you want to keep that format.

Document Source Types

Supported document.source variants on this surface are:

{"type":"url","url":"https://..."}
{"type":"base64","media_type":"application/pdf","data":"..."}
{"type":"text","media_type":"text/plain","data":"..."}
{"type":"content","content": ... }

URL
Base64
Text
Content

Use this when the document is already hosted and reachable by URL.

{
  "type": "url",
  "url": "https://example.com/report.pdf"
}

Use this when you need to send the PDF inline as a base64 payload.

{
  "type": "base64",
  "media_type": "application/pdf",
  "data": "JVBERi0xLjQ..."
}

Use this when the source is already extracted plain text rather than a raw PDF binary.

{
  "type": "text",
  "media_type": "text/plain",
  "data": "Section 1: ..."
}

Use this when you want the document source itself to be built from typed content blocks.

{
  "type": "content",
  "content": [
    {
      "type": "text",
      "text": "Inside doc"
    }
  ]
}

When to use this surface

you already depend on Messages document semantics
your app needs PDFs or other document-like content inside an Anthropic-style conversation

If you are starting fresh, compare this with Responses Multimodal Inputs.

PDF URL Example

from anthropic import Anthropic

client = Anthropic(
    base_url="https://api.naga.ac",
    api_key="YOUR_API_KEY",
)

message = client.messages.create(
    model="claude-sonnet-4.5",
    max_tokens=256,
    messages=[
        {
            "role": "user",
            "content": [
                {
                    "type": "document",
                    "title": "Quarterly Report",
                    "source": {
                        "type": "url",
                        "url": "https://example.com/report.pdf",
                    },
                },
                {
                    "type": "text",
                    "text": "What are the key findings in this document?",
                },
            ],
        }
    ],
)

print(message.content)

import Anthropic from '@anthropic-ai/sdk';

const client = new Anthropic({
  baseURL: 'https://api.naga.ac',
  apiKey: 'YOUR_API_KEY',
});

const message = await client.messages.create({
  model: 'claude-sonnet-4.5',
  max_tokens: 256,
  messages: [
    {
      role: 'user',
      content: [
        {
          type: 'document',
          title: 'Quarterly Report',
          source: {
            type: 'url',
            url: 'https://example.com/report.pdf',
          },
        },
        {
          type: 'text',
          text: 'What are the key findings in this document?',
        },
      ],
    },
  ],
});

console.log(message.content);

curl https://api.naga.ac/v1/messages \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-sonnet-4.5",
    "max_tokens": 256,
    "messages": [
      {
        "role": "user",
        "content": [
          {
            "type": "document",
            "title": "Quarterly Report",
            "source": {
              "type": "url",
              "url": "https://example.com/report.pdf"
            }
          },
          {
            "type": "text",
            "text": "What are the key findings in this document?"
          }
        ]
      }
    ]
  }'

Content-Source Example

The compatibility layer also accepts content-source documents.

{
  "role": "user",
  "content": [
    {
      "type": "document",
      "title": "Spec",
      "source": {
        "type": "content",
        "content": [
          {
            "type": "text",
            "text": "Inside doc"
          }
        ]
      }
    }
  ]
}

Caveats

document support still depends on the selected model
large PDFs increase token usage after provider-side parsing
use this API only when you specifically need Anthropic-compatible document semantics

Common mistakes

assuming every model that supports text also supports document blocks
sending very large documents without expecting higher token cost
mixing Messages document syntax with Chat Completions or Responses file syntax

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Document Source Types

When to use this surface

PDF URL Example

Content-Source Example

Caveats

Common mistakes

​Document Source Types

​When to use this surface

​PDF URL Example

​Content-Source Example

​Caveats

​Common mistakes

​Related Docs

Document Source Types

When to use this surface

PDF URL Example

Content-Source Example

Caveats

Common mistakes

Related Docs